This invention relates to photographic materials. In a preferred form it relates to a photographic reflective images.

In the formation of color paper it is known that the base paper has applied thereto a layer of polymer, typically polyethylene. This layer serves to provide waterproofing to the paper, as well as providing a smooth surface on which the photosensitive layers are formed. The formation of a suitably smooth surface is difficult requiring great care and expense to ensure proper laydown and cooling of the polyethylene layers. The formation of a suitably smooth surface would also improve image quality as the display material would have more apparent blackness as the reflective properties of the improved base are more specular than the prior materials. As the whites are whiter and the blacks are blacker, there is more range in between and, therefore, contrast is enhanced. It would be desirable if a more reliable and smoother surface could be formed at less expense.

Prior art photographic reflective photographic papers are coated with light sensitive silver halide imaging layers on one side of the paper and thus images only appear on one side of the photographic paper. Typically, the side opposite the imaging layers contains the manufacture brand name and is coated with an antistatic coating. Prior art photographic paper is typically conveyed on the backside during manufacture of the paper and in photographic processing as contact with the numerous rollers and platens in manufacturing and photographic image processing would scratch the imaging layers reducing the quality of the image. Further, photographic printing equipment is currently configured to print only one side of the photographic paper.

Prior art two-sided photographs or reflective photographs with images on both sides are accomplished by printing two separate photographs and adhesively adhering the two photographs after imaging processing. While this process does yield a two-sided photograph, it is expensive and time consuming as thickness of the two-sided photograph is excessive. The thick, two-sided image is difficult to handle, expensive to mail and does not easily fit into photographic albums and frames designed for a single thickness of paper.

It has been proposed in U.S. 5,866,282 Bourdelais et al to utilize a composite support material with laminated biaxially oriented polyolefin sheets as a photographic imaging material. In U.S. 5,866,282, biaxially oriented polyolefin sheets are extrusion laminated to cellulose paper to create a support for silver halide imaging layers. The biaxially oriented sheets described in U.S. 5,866,282 have a microvoided layer in combination with coextruded layers that contain white pigments. The composite imaging support structure described in U.S. 5,866,282 has been found to be more durable, sharper and brighter than prior art photographic paper imaging supports that use cast melt extruded polyethylene layers coated on cellulose paper.

Typically, photographic reflective imaging layers are coated on a polyethylene coated cellulose paper. While polyethylene coated cellulose paper does provide an acceptable support for the imaging layers, there is a need for alternate support materials such as polyester or fabric. The problem with alternate, non paper supports is the lack of robustness in photographic processing equipment to mechanical property changes in supports. The photographic processing equipment will not run photographic materials that have significantly different mechanical properties than prior art photographic materials. It would be desirable if a reflective photographic image could be efficiently formed on alternate supports.

The continuing thrust towards digital printing of photographic color papers has created the need for a consumer color paper that can work in both a negative working optical and digital exposure equipment. In order for a color paper to correctly print, utilizing a color negative curve shape of the paper is critical. In a digital environment (direct writing) to a photographic paper, the curve shape to a degree can be electomodulated and thus have a greater degree of freedom than the color negative working system. Ideally, a color paper that could substantially maintain tone scale from conventional optical negative working exposure times to sub microsecond digital direct writing exposure times would be preferred. This would enable a photofinishing area to maintain one paper for both digital and optical exposure thereby reducing the need for expensive inventory.

An example of conventional photographic member is disclosed in US-A-4 768 811.

There is a continuing need for silver halide images that can be efficiently printed on both sides of the photographic paper. Further, there is also continuing need for photographic elements that are more durable in use and lighter weight for handling during the formation, imaging, and development process.

It is an object of the invention to provide a silver halide image printed on both sides of the support.

It is an another of the invention to overcome disadvantages of prior art and practices.

It is another object to provide photographic elements that are light weight and thin for ease of handling during formation of the element and its imaging and development.

It is a further object to provide photographic elements that may be easily provided in finished form with a variety of substrates.

These and other objects of the invention are accomplished by a photographic member as defined in claim 1 and the method of forming a photographic member as defined in claim 8.

The invention provides a photographic element that has images printed on both sides, light in weight for ease of formation, imaging and development but may be easily adhered to a variety of substrates.

• Fig. 1 is an illustration of the folding of the image element around the planner partitioning member.
• Fig. 2 is an illustration of the element of the invention exhibiting a two-sided image.

The invention has numerous advantages over prior photographic elements. The two-sided photograph of the invention allows for high quality silver halide reflective images to be printed on the front side and the back side of a photograph. A two-sided photograph has allows a 50% reduction in storage space for images as a single thickness of photograph contains two images. Further, several cost reductions are now possible as mailing and shipping cost have been reduced by 50% and the amount of reflective support material is also reduced by 50% since one thickness of reflective support material yields two images. By binding the two-sided print, photographic books and albums are possible and are thin because the support thickness has been reduced by 50% compared to the prior art technique to adhering two one sided images back to back.

The two-sided image may also be utilized to print critical information on the back side of the image. Personal information such as time, date and location of a photograph can now be silver halide printed on the back side of the two-sided image allowing for each photograph to be personalized. The two-sided image can also be utilized for localized advertisement on the back side of the image. Advertisements such as continuity coupons, branding by the photographic processing lab and promotional contests.

Digital printing of the image either through a digital working silver halide printing system or through ink jet printing allows information such as exposure information, date and time of exposure and subject matter to be attached to the image easily and without fear of loss of this critical information. Further, digital printing, especially in the silver halide imaging layers allows for improved image sharpness and dye hue of the color couplers utilized in this invention.

The elements of the invention are also lighter in weight and thickness so that a roll of the photographic element of the same diameter will contain many more linear feet resulting in many more images per roll. The imaging element of the invention after development may be easily adhered to a variety of reflective substrates, thereby allowing customized use of the images. It may be desirable for images that will be mailed to be adhered to a lightweight substrate, whereas images to be displayed can easily be adhered to a heavy substrate after their development. The base material that is utilized in mounting of the photographic images of the invention may be lower in cost, as it is not present during development of the image and not subjected to the development chemicals. The problem of dusting during slitting and chopping of photographic elements is greatly minimized, as slitting and chopping takes place when there is no base substrate present. These and other advantages will be apparent from the detailed description below.

The term as used herein, "transparent" means the ability to pass radiation without significant deviation or absorption. For this invention, "transparent" material is defined as a material that has a spectral transmission greater than 90%. For a photographic element, spectral transmission is the ratio of the transmitted power to the incident power and is expressed as a percentage as follows; T_RGB=10^-D *100 where D is the average of the red, green and blue Status A transmission density response measured by an X-Rite model 310 (or comparable) photographic transmission densitometer. For this invention, "reflective" print material or base or polymer base is defined as a material that has a spectral transmission of 20% or less.

For the photographic element of this invention the light sensitive emulsion layer is coated onto a thin oriented polymer sheet with an emulsion adhesion layer. This photographic element can then be printed with images using conventional exposure technology or digital exposure technology and processed using traditional photographic chemistry. Two sequential exposures of the thin transparent oriented polymer sheet with the developed image are preferably folded around a reflective planar partitioning member and then subsequently adhered to the planar partitioning member yielding a photographic member with an image located on both sides of the photographic member. This method for creating a two-sided print is preferred as the cost of the base material is reduced by 50% as two images are supported by only one reflective base element.

The image on one or both sides of the planner partitioning member preferably comprises a full color image. Full color images allow consumers to view the captured image as it occurred in nature. In another embodiment, the image on one or both sides preferably comprises a black and white image. Black and white images are preferred as they typically provide a wide range of contrast and have excellent image life as black and white images utilize retained silver to create density in an image. With the use of digital printing one image may be color, while the second image may be back and white as digital printing technology can utilize color couplers exposed with the same amount of red, green and blue light energy to create a shades of gray while utilizing the same development chemistry. A two-sided image with a full color image on one side and a black and white image on the other has significant commercial value in that the same image can be viewed in color and black and white on the same photographic member.

By utilizing digital printing methods such as lasers and CRT printers, the second exposure for the two-sided photographic member can also be utilized for the printing of the same image that has been corrected by a image printing algorithm to provide the consumer with two different printing settings. The second exposure can also be utilized to provide stock photographic images that are consistent with the theme of the photographic subject. For example, the subject matter of the images comprises nature scenes, stock photographic images of nature scenes can be printed to add to the viewing pleasure of the consumer.

In the two-sided photographic image, one side preferably contains text. The ability to print text on an image is preferred as this would allow important information such as exposure information, date and time of image and subject identification to be printed on one side of the photographic image and remain with the image for the lifetime of the image. For example, the date, time and exposure conditions at the time of capture can be recorded on a magnetic strip located on the capture film in a camera. The magnetic strip is read at time of processing and printed on the second exposure of the two-sided image. After folding and adhesion to the planer partitioning member, the date, time and exposure information from the camera is located on the side opposite the image. The silver halide printing of text on the photographic member also allows for unique branding as the name and location of the processing lab can be printed on one side of the photographic element. Further, the text can be utilized for advertisement, promotions or a pre addressed mailing label including a photographic stamp, specified by the consumer, for photographic post cards.

Since the oriented polymer base of this invention is tough and strong, the sheet will protect the developed image from scratches, dust and fingerprints compared to prior art developed silver halide images which use a delicate hardened gelatin layer for protection. Further, since the oriented sheet is waterproof, it provides spill protection from liquids such as coffee, ink and water. Protecting the developed silver halide image has significant commercial value in that the current developed silver halide image structure offers little protection from consumer mishandling of images.

After the folding of the developed image on the polymer base, the photographic element is preferably adhered to the partitioning member with the developed image adjacent to the partitioning member. The developed image adjacent to the partitioning member allows for the image to be protected as the polymer base in on the exposed surfaces. Protecting the imaging layers has significant commercial value in that developed silver halide images are delicate and fragile. By protecting the images with a strong polymer base, the developed image can survive repeated handling by consumers while preserving image quality. Further, because the image is protected, the developed image can now be utilized in non traditional imaging applications such as packaging material, wrapping paper and identification cards.

The oriented polymer base is thin, preferably less than 100 micrometers. A thin polymer base has the advantage of allowing longer rolls of light sensitive silver halide coated rolls compared with thick cellulose paper based utilized in prior art materials. The thin polymer base also significantly reduces shipping cost of developed images as the thin biaxially oriented polymer sheet of the invention weight significantly less than prior art photographic paper. A thin sheet is also necessary to reduce unwanted reduction in the transparency of the biaxially oriented sheet resulting in a cloudy image as the thin biaxially oriented sheet is laminated to a reflective support.

Another unique feature of this invention is the addition of an antihalation layer to the imaging layers. The antihalation layer prevents unwanted secondary exposure of the silver crystals in the imaging layer as light is absorbed in the antihalation layer during exposure. The prevention of secondary exposure of the light sensitive silver crystals, will significantly increase the sharpness of the image and preserve the inherent dye hue of the couplers utilized in the invention without the use of TiO₂ which is commonly used in prior art reflective photographic print materials.

Surprisingly, it has also been found that polymer chemistry can be added to the biaxially oriented polymer sheet to provide ultraviolet protection to the color couplers used in the developed image layer. Traditionally, this protection for prior art materials has been provided in the gelatin overcoat layer. The incorporation of the ultraviolet protection materials in the biaxially oriented polymer sheet of this invention provides better ultraviolet protection to the imaging couplers and is lower in cost as less ultraviolet filter materials are required in the biaxially oriented sheet than in a gelatin overcoat.

By printing and developing the images on the oriented polymer base, folding the imaged polymer base around a planar partitioning member and then adhering the imaged polymer base to the planar partitioning member, this invention avoids many of the problems associated with coating the light sensitive emulsions on to a photographic base containing cellulose paper. Problems that are avoided by applying the light sensitive silver halide layers to the oriented polymer include paper dusting during slitting and punching, edge penetration of processing chemicals into the exposed paper along the slit edge and unwanted secondary reflection caused by the paper base. Further, for prior art photographic reflective print materials, great care must be taken to ensure that the paper base does not chemically sensitize the light sensitive image layers prior to processing. By joining the imaging layers with a reflective planar partitioning member after processing, the criticalities of the chemical sensitization of the base have been removed. Joining of the imaging layers of this invention with a reflective planar partitioning member after processing would allow many different types of planar partitioning members to be utilized, offering the consumer a wide range of options such as paper, polymer base or fabric base that at present are not widely available.

Illustrated in Fig. 1 is an illustration of the folding of the image element around the planner partitioning member. Polymer base 14 containing imaging layers 12 is folded around planner partitioning member 10. The polymer base 14 containing imaging layers 12 are folded around pivot point 16. Illustrated in Fig. 2 is the element of the invention exhibiting a two-sided image. Two-sided imaging element 26 comprises planner partitioning member 18. Folded around planner partitioning member 18 is the polymer base 24 containing imaged layer 22. Imaged layer 22 is adhesively attached to planner partitioning member 18 with adhesive layer 20 to create two-sided imaging element 26.

The polymer base to which the light sensitive silver halide imaging layers are coated preferably is transparent. A transparent polymer base is required as the images will be viewed through the polymer base. A biaxially oriented polymer base is preferred as biaxial orientation of a polymer increases the toughness and the ability to carry the light sensitive silver halide imaging layers though manufacturing and the imaging development process. Biaxially oriented polymer bases are conveniently manufactured by coextrusion of the base, which may contain several layers, followed by biaxial orientation. Such biaxially oriented bases are disclosed in, for example, U.S. Pat. No. 4,764,425.

Suitable classes of thermoplastic polymers for the biaxially oriented baseinclude polyolefins, polyesters, polyamides, polycarbonates, cellulosic esters, polystyrene, polyvinyl resins, polysulfonamides, polyethers, polyimides, polyvinylidene fluoride, polyurethanes, polyphenylenesulfides, polytetrafluoroethylene, polyacetals, polysulfonates, polyester ionomers, and polyolefin ionomers. Copolymers and/or mixtures of these polymers can be used.

Polyolefins particularly polypropylene, polyethylene, polymethylpentene, and mixtures thereof are preferred. Polyolefin copolymers, including copolymers of propylene and ethylene such as hexene, butene and octene are also preferred. Polypropylenes are most preferred polyolefin polymers because they are low in cost and have good strength and surface properties and are transparent after orientation.

Preferred polyesters of the invention include those produced from aromatic, aliphatic or cycloaliphatic dicarboxylic acids of 4-20 carbon atoms and aliphatic or alicyclic glycols having from 2-24 carbon atoms. Examples of suitable dicarboxylic acids include terephthalic, isophthalic, phthalic, naphthalene dicarboxylic acid, succinic, glutaric, adipic, azelaic, sebacic, fumaric, maleic, itaconic, 1,4-cyclohexanedicarboxylic, sodiosulfoisophthalic and mixtures thereof. Examples of suitable glycols include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, 1,4-cyclohexanedimethanol, diethylene glycol, other polyethylene glycols and mixtures thereof. Such polyesters are well known in the art and may be produced by well known techniques, e.g., those described in U.S. Pat. Nos. 2,465,319 and U.S. 2,901,466. Preferred continuous matrix polyesters are those having repeat units from terephthalic acid or naphthalene dicarboxylic acid and at least one glycol selected from ethylene glycol, 1,4-butanediol and 1,4-cyclohexanedimethanol. Poly(ethylene terephthalate), which may be modified by small amounts of other monomers, is especially preferred. Other suitable polyesters include liquid crystal copolyesters formed by the inclusion of suitable amount of a co-acid component such as stilbene dicarboxylic acid. Examples of such liquid crystal copolyesters are those disclosed in U.S. Patent Nos. 4,420,607; 4,459,402; and 4,468,510.

Polyester is the most preferred polymer for use as a transparent polymer base because the polyester polymer is high in strength and is transparent after orientation. Further, polyester polymer has been found to have sufficient modulus to provide a photographic member that is low in curl and highly tear resistant providing an image that can withstand the rigors of consumer handling. Finally, polyester polymer has been shown to reduce the flow of oxygen and nitrogen which have been shown to catalyze the fading of color couplers.

Useful polyamides include nylon 6, nylon 66, and mixtures thereof. Copolymers of polyamides are also suitable continuous phase polymers. An example of a useful polycarbonate is bisphenol-A polycarbonate. Cellulosic esters suitable for use as the continuous phase polymer of the composite sheets include cellulose nitrate, cellulose triacetate, cellulose diacetate, cellulose acetate propionate, cellulose acetate butyrate, and mixtures or copolymers thereof. Useful polyvinyl resins include polyvinyl chloride, poly(vinyl acetal), and mixtures thereof. Copolymers of vinyl resins can also be utilized.

The polymer base preferably is provided with an integral emulsion adhesion layer to avoid the need for expensive primer and sub coatings known in the art to improve gelatin adhesion to polymer sheets. An example of a suitable integral emulsion adhesion layer is described in U.S. 5,866,282 (Bourdelais et al.). The most preferred integral emulsion adhesion layer is a layer of polyethylene that is CDT treated prior to the coating of light sensitive silver halide imaging layers.

The polymer base may preferably be supplied with a variety of coatings referred to hereon as shield layers, that will protect the polymer base from scratching, finger printing and static. Suitable coatings include but are not limited to urethane polymer, silicates and waxes. The surface of the polymer base preferably is rough to create a stand-off between oils present in fingerprints and the polymer base. The preferred roughness average is between 0.20 and 3.0 micrometers. Below 0.18 micrometers, little improvement in fingerprint resistance is observed. Above 4.0 micrometers, the rough side of the polymer base beings to emboss the light sensitive silver halide layers when the light sensitive silver halide coated polymer base is wound in a roll.

In another embodiment of the invention, the polymer base is white and reflective. A white reflective polymer base is preferred as the printing speed of a reflective polymer base is superior to that of a clear polymer base. A white reflective polymer base also reduces the amount of light reflection that is required by the planer partitioning member allowing the use of a low cost partitioning member. When a white reflective partitioning member is utilized, the developed image applied to the reflective polymer base is preferably attached to the partitioning member with the polymer base adjacent to the partitioning member. The polymer base is adjacent to the partitioning member because the images can not be viewed through the reflective polymer base.

Since the polymer base onto which the light sensitive silver halide layers are applied typically is thin, a reflective planer partitioning member is required to provide stiffness to the image and provide reflective properties for viewing in ambient lighting conditions. A planer partitioning member that has a stiffness of at least 150 milinewtons is preferred as image stiffness less than 130 milinewtons has been shown to be perceived as low in quality as the consumer associates high quality with a stiff image. A planer partitioning member that has an L^* greater than 92.0 is preferred as planer partitioning members with L* less than 91.0 are not bright enough for a high quality reflective image. A white planer partitioning member is preferred as the white content or density minimum areas in an image are created by the whiteness of the base because silver halide imaging systems can not as of yet create the color "white".

A planer partitioning member that has an opacity of at least 88 is preferred because two-sided images with a planer partitioning member with an opacity of less than 85 will create image interference as the images are viewed when back lighting is present as is the case when images are viewed in front of a sunlit window.

The planer partitioning member preferably comprises cellulose paper. Cellulose paper is preferred as cellulose paper is low in cost compared to polymer alternatives. Further, cellulose paper is light in weight and has acceptable opacity as the air voids in a cellulose paper sheet provide opacity without the expensive need for white pigments such as TiO₂ and calcium carbonate. Examples of suitable cellulose papers for a planer partitioning member are those disclosed in U.S. Pat. Nos. 5,244,861; 5,866,282; 5,290,672; and 5,466,519.

Another preferred planer partitioning member comprises a polymer. A polymer planer partitioning member is typically smooth resulting in a high quality glossy image. Further, addenda may be added to the polymer planer partitioning member to improve the sharpness and whiteness of the image and the opacity of the photographic member. Addenda such as white pigments to improve the density minimum areas of the image, optical brightener to prove a blue tint to the density minimum areas and blue tint to offset the native yellowness of the gelatin utilized in the silver halide imaging members. Examples of suitable polymers for a planer partitioning member are those disclosed in U.S. Pat. Nos. 4,912,333; 4,994,312; 5,055,371; and 4,187,133.

The planer partitioning member preferably comprises a composite structure that includes both a cellulose paper and polymer coatings and or sheets applied to the surface of the cellulose paper. A composite structure consisting of a cellulose paper base and a polymer for the planer partitioning member allows for a low cost, high quality planer partitioning member as this combination allows for the use of low cost of cellulose paper to be used in combination with the desirable performance characteristics of a polymer coating or sheet. Examples of suitable cellulose paper, polymer combinations for a planer partitioning member are those disclosed in U.S. Pat. Nos. 5,866,282; 5,874,205; 5,888,681; and 5,466,519.

The imaging element is formed by exposing and developing an images on a polymer base. After development a 180 degree fold is created at every other developed image. After the 180 degree fold, the planer partitioning member is inserted between the folded images and adhered on both sides to the imaging layers. The fold may be created by techniques known in the packaging art to create folds in polymer materials. Another preferred method for the folding of the developed photographic image is around the planer partitioning member. The developed image on the polymer base is folded around one edge of the planer partitioning member and subsequently adhered to the planer partitioning member.

To adhere the transparent sheet with the developed image layers to the planer partitioning member a bonding layer is required. The bonding layer must provide excellent adhesion between the imaging layers and the planer partitioning member for the useful life of the image. The preferred method of adhering the imaging layers and planer partitioning member is by use of an adhesive. The adhesive preferably is coated or applied to the planer partitioning member. The adhesive preferably is a pressure sensitive adhesive or heat activated adhesive. During the bonding process, the imaging layers is adhered to the planer partitioning member by use of a nip roller or a heated nip roll in the case of a heat activated adhesive. A preferred pressure sensitive adhesive is an acrylic based adhesive. Acrylic adhesives have been shown to provide an excellent bond between gelatin developed imaging layers and biaxially oriented polymer base sheets.

The preferred thickness of the adhesive layer is between 2 and 40 micrometers. Below 1 micrometer, uniformity of the adhesive is difficult to maintain leading to undesirable coating skips. Above 45 micrometers, little improvement in adhesion and coating quality is observed and therefore increased adhesive is not cost justified. An important property of the adhesion layer between the developed silver halide imaging layers and the planer partitioning member is the optical transmission of the adhesive layer. A laminated adhesive layer with an optical transmission greater than 90% is preferred at the adhesive should not interfere with the quality of the image.

While most of the discussion has been directed toward silver halide imaging layers, ink jet printing of the image is also preferred. Ink jet printing of the image has several advantages compared to silver halide images. Ink jet printed images are printed from a digital file and, thus, are optimized to provide text on one or both of the images. Ink jet printing systems do not require the development process to create an image and thus are better adapted to areas of the world where chemical effluent presents a problem. Further, inks can be pigmented to provide outstanding image life. The invention also protects the printed image layer from handling damage and environmental solvents such as water which have been a traditional weakness of ink jet printed images and prevents ink jet printing technology from being widely utilized to print consumer images.

The dye receiving layer or DRL for ink jet imaging may be applied by any known methods. Such as solvent coating, or melt extrusion coating techniques. The DRL is coated over the TL at a thickness ranging from 0.1 - 10 µm, preferably 0.5 - 5 µm. There are many known formulations which may be useful as dye receiving layers. The primary requirement is that the DRL is compatible with the inks which it will be imaged so as to yield the desirable color gamut and density. As the ink drops pass through the DRL, the dyes are retained or mordanted in the DRL, while the ink solvents pass freely through the DRL and are rapidly absorbed by the TL. Additionally, the DRL formulation is preferably coated from water, exhibits adequate adhesion to the TL, and allows for easy control of the surface gloss.

For example, Misuda et al in US Patents 4,879,166; 5,264,275; 5,104,730; 4,879,166; and Japanese patents 1,095,091; 2,276,671; 2,276,670; 4,267,180; 5,024,335; and 5,016,517 disclose aqueous based DRL formulations comprising mixtures of psuedo-bohemite and certain water soluble resins. Light in US Patents 4,903,040; 4,930,041; 5,084,338; 5,126,194; 5,126,195; 5,139,867; and 5,147,717 disclose aqueous-based DRL formulations comprising mixtures of vinyl pyrrolidone polymers and certain water-dispersible and/or water-soluble polyesters, along with other polymers and addenda. Butters et al in US Patents 4,857,386 and 5,102,717 disclose ink-absorbent resin layers comprising mixtures of vinyl pyrrolidone polymers and acrylic or methacrylic polymers. Sato et al in US Patent 5,194,317 and Higuma et al in US Patent 5,059,983 discloses aqueous-coatable DRL formulations based on poly (vinyl alcohol). Iqbal in US Patent 5,208,092 discloses water-based IRL formulations comprising vinyl copolymers which are subsequently cross-linked. In addition to these examples, there may be other known or contemplated DRL formulations which are consistent with the aforementioned primary and secondary requirements of the DRL, all of which fall under the spirit and scope of the current invention.

The preferred DRL is a 0.1 - 10 µm DRL which is coated as an aqueous dispersion of 5 parts alumoxane and 5 parts poly (vinyl pyrrolidone). The DRL may also contain varying levels and sizes of matting agents for the purpose of controlling gloss, friction, and/or fingerprint resistance, surfactants to enhance surface uniformity and to adjust the surface tension of the dried coating, mordanting agents, antioxidants, UV absorbing compounds, light stabilizers, and the like.

Although the ink-receiving elements as described above can be successfully used to achieve the objectives of the present invention, it may be desirable to overcoat the DRL for the purpose of enhancing the durability of the imaged element. Such overcoats may be applied to the DRL either before or after the element is imaged. For example, the DRL can be overcoated with an ink-permeable layer through which inks freely pass. Layers of this type are described in US Patents 4,686,118; 5,027,131; and 5,102,717 in European Patent Specification 0 524 626. Alternatively, an overcoat may be added after the element is imaged. Any of the known laminating films and equipment may be used for this purpose. The inks used in the aforementioned imaging process are well known, and the ink formulations are often closely tied to the specific processes, i.e., continuous, piezoelectric, or thermal. Therefore, depending on the specific ink process, the inks may contain widely differing amounts and combinations of solvents, colorants, preservatives, surfactants, humectants, and the like. Inks preferred for use in combination with the image recording elements of the present invention are water-based, such as those currently sold for use in the Hewlett-Packard Desk Writer 560C printer. However, it is intended that alternative embodiments of the image-recording elements as described above, which may be formulated for use with inks which are specific to a given ink-recording process or to a given commercial vendor, fall within the scope of the present invention.

Disclosed below is a suitable flesh tone optimized light sensitive silver halide emulsion capable of accurately reproducing flesh tones. This invention is directed to a silver halide depth image of excellent performance when exposed by either an electronic printing method or a conventional optical printing method. An electronic printing method comprises subjecting a radiation sensitive silver halide emulsion layer of a recording element to actinic radiation of at least 10^-4 ergs/cm² for up to 100 µ seconds duration in a pixel-by-pixel mode wherein the silver halide emulsion layer is comprised of silver halide grains as described above. A conventional optical printing method comprises subjecting a radiation sensitive silver halide emulsion layer of a recording element to actinic radiation of at least 10^-4 ergs/cm² for 10^-3 to 300 seconds in an imagewise mode wherein the silver halide emulsion layer is comprised of silver halide grains as described above.

If the polymer base is coated with light sensitive silver halide imaging layers on both sides of the polymer base, a two-sided depth imaging material is the result. Developed images in registration separated by the transparent polymer base convey a sense of depth and have significant commercial value. The depth imaging material wherein at least one dye forming coupler on the bottom side of the imaging support has less dye forming coupler than the imaging layer on the top side is preferred because it allows for an increase in image density without increasing developer time. The depth imaging material of this invention wherein the amount of dye forming coupler is substantially the same on the top and bottom sides is most preferred because it allows for optimization of image density while allowing for developer time less than 50 seconds. Further, coating substantially the same amount of light sensitive silver halide emulsion on both sides has the additional benefit of balancing the imaging element for image curl caused by the contraction and expansion of the hydroscopic gel typically found in photographic emulsions.

This invention in a preferred embodiment utilizes a radiation-sensitive emulsion comprised of silver halide grains (a) containing greater than 50 mole percent chloride, based on silver, (b) having greater than 50 percent of their surface area provided by {100} crystal faces, and (c) having a central portion accounting for from 95 to 99 percent of total silver and containing two dopants selected to satisfy each of the following class requirements: (i) a hexacoordination metal complex which satisfies the formula (I) [ML₆]ⁿ wherein n is zero, -1, -2, -3 or -4; M is a filled frontier orbital polyvalent metal ion, other than iridium; and L₆ represents bridging ligands which can be independently selected, provided that least four of the ligands are anionic ligands, and at least one of the ligands is a cyano ligand or a ligand more electronegative than a cyano ligand; and (ii) an iridium coordination complex containing a thiazole or substituted thiazole ligand.

It has been discovered quite surprisingly that the combination of dopants (i) and (ii) provides greater reduction in reciprocity law failure than can be achieved with either dopant alone. Further, unexpectedly, the combination of dopants (i) and (ii) achieve reductions in reciprocity law failure beyond the simple additive sum achieved when employing either dopant class by itself. It has not been reported or suggested prior to this invention that the combination of dopants (i) and (ii) provides greater reduction in reciprocity law failure, particularly for high intensity and short duration exposures. The combination of dopants (i) and (ii) further unexpectedly achieves high intensity reciprocity with iridium at relatively low levels, and both high and low intensity reciprocity improvements even while using conventional gelatino-peptizer (e.g., other than low methionine gelatino-peptizer).

In a preferred practical application, the advantages of the invention can be transformed into increased throughput of digital substantially artifact-free color print images while exposing each pixel sequentially in synchronism with the digital data from an image processor.

In one embodiment, the present invention represents an improvement on the electronic printing method. Specifically, this invention in one embodiment is directed to an electronic printing method which comprises subjecting a radiation sensitive silver halide emulsion layer of a recording element to actinic radiation of at least 10^-4 ergs/cm² for up to 100 µ seconds duration in a pixel-by-pixel mode. The present invention realizes an improvement in reciprocity failure by selection of the radiation sensitive silver halide emulsion layer. While certain embodiments of the invention are specifically directed towards electronic printing, use of the emulsions and elements of the invention is not limited to such specific embodiment, and it is specifically contemplated that the emulsions and elements of the invention are also well suited for conventional optical printing.

It has been unexpectedly discovered that significantly improved reciprocity performance can be obtained for silver halide grains (a) containing greater than 50 mole percent chloride, based on silver, and (b) having greater than 50 percent of their surface area provided by {100} crystal faces by employing a hexacoordination complex dopant of class (i) in combination with an iridium complex dopant comprising a thiazole or substituted thiazole ligand. The reciprocity improvement is obtained for silver halide grains employing conventional gelatino-peptizer, unlike the contrast improvement described for the combination of dopants set forth in U.S. Patents 5,783,373 and 5,783,378, which requires the use of low methionine gelatino-peptizers as discussed therein, and which states it is preferable to limit the concentration of any gelatino-peptizer with a methionine level of greater than 30 micromoles per gram to a concentration of less than 1 percent of the total peptizer employed. Accordingly, in specific embodiments of the invention, it is specifically contemplated to use significant levels (i.e., greater than 1 weight percent of total peptizer) of conventional gelatin (e.g., gelatin having at least 30 micromoles of methionine per gram) as a gelatino-peptizer for the silver halide grains of the emulsions of the invention. In preferred embodiments of the invention, gelatino-peptizer is employed which comprises at least 50 weight percent of gelatin containing at least 30 micromoles of methionine per gram, as it is frequently desirable to limit the level of oxidized low methionine gelatin which may be used for cost and certain performance reasons.

In a specific, preferred form of the invention it is contemplated to employ a class (i) hexacoordination complex dopant satisfying the formula: (I) [ML₆]ⁿ where

   n is zero, -1, -2, -3 or -4;

   M is a filled frontier orbital polyvalent metal ion, other than iridium, preferably Fe⁺², Ru⁺², Os⁺², Co⁺³, Rh⁺³, Pd⁺⁴ or Pt⁺⁴, more preferably an iron, ruthenium or osmium ion, and most preferably a ruthenium ion;

   L₆ represents six bridging ligands which can be independently selected, provided that least four of the ligands are anionic ligands and at least one (preferably at least 3 and optimally at least 4) of the ligands is a cyano ligand or a ligand more electronegative than a cyano ligand. Any remaining ligands can be selected from among various other bridging ligands, including aquo ligands, halide ligands (specifically, fluoride, chloride, bromide and iodide), cyanate ligands, thiocyanate ligands, selenocyanate ligands, tellurocyanate ligands, and azide ligands. Hexacoordinated transition metal complexes of class (i) which include six cyano ligands are specifically preferred.

Illustrations of specifically contemplated class (i) hexacoordination complexes for inclusion in the high chloride grains are provided by Olm et al U.S. Patent 5,503,970 and Daubendiek et al U.S. Patents 5,494,789 and 5,503,971, and Keevert et al U.S. Patent 4,945,035, as well as Murakami et al Japanese Patent Application Hei-2[1990]-249588, and Research Disclosure Item 36736. Useful neutral and anionic organic ligands for class (ii) dopant hexacoordination complexes are disclosed by Olm et al U.S. Patent 5,360,712 and Kuromoto et al U.S. Patent 5,462,849.

Class (i) dopant is preferably introduced into the high chloride grains after at least 50 (most preferably 75 and optimally 80) percent of the silver has been precipitated, but before precipitation of the central portion of the grains has been completed. Preferably class (i) dopant is introduced before 98 (most preferably 95 and optimally 90) percent of the silver has been precipitated. Stated in terms of the fully precipitated grain structure, class (i) dopant is preferably present in an interior shell region that surrounds at least 50 (most preferably 75 and optimally 80) percent of the silver and, with the more centrally located silver, accounts the entire central portion (99 percent of the silver), most preferably accounts for 95 percent, and optimally accounts for 90 percent of the silver halide forming the high chloride grains. The class (i) dopant can be distributed throughout the interior shell region delimited above or can be added as one or more bands within the interior shell region.

Class (i) dopant can be employed in any conventional useful concentration. A preferred concentration range is from 10^-8 to 10^-3 mole per silver mole, most preferably from 10^-6 to 5 X 10^-4 mole per silver mole.

The following are specific illustrations of class (i) dopants: (i-1)   [Fe(CN)₆]^-4 (i-2)   [Ru(CN)₆]^-4 (i-3)   [Os(CN)₆]^-4 (i-4)   [Rh(CN)₆]^-3 (i-5)   [Co(CN)₆]^-3 (i-6)   [Fe(pyrazine)(CN)₅]^-4 (i-7)   [RuCl(CN)₅]^-4 (i-8)   [OsBr(CN)₅]^-4 (i-9)   [RhF(CN)₅]^-3 (i-10)   [In(NCS)₆]^-3 (i-11)   [FeCO(CN)₅]^-3 (i-12)   [RuF₂(CN)₄]^-4 (i-13)   [OsCl₂(CN)₄]^-4 (i-14)   (RhI₂(CN)₄]^-3 (i-15)   [Ga(NCS)₆]^-3 (i-16)   [Ru(CN)₅(OCN)]^-4 (i-17)   [Ru(CN)₅(N₃)]^-4 (i-18)   [Os(CN)₅(SCN)]^-4 (i-19)   [Rh(CN)₅(SeCN)]^-3 (i-20)   [Os(CN)Cl₅]^-4 (i-21)   [Fe(CN)₃Cl₃]^-3 (i-22)   [Ru(CO)₂(CN)₄]^-1

When the class (i) dopants have a net negative charge, it is appreciated that they are associated with a counter ion when added to the reaction vessel during precipitation. The counter ion is of little importance, since it is ionically dissociated from the dopant in solution and is not incorporated within the grain. Common counter ions known to be fully compatible with silver chloride precipitation, such as ammonium and alkali metal ions, are contemplated. It is noted that the same comments apply to class (ii) dopants, otherwise described below.

The class (ii) dopant is an iridium coordination complex containing at least one thiazole or substituted thiazole ligand. Careful scientific investigations have revealed Group VIII hexahalo coordination complexes to create deep electron traps, as illustrated R. S. Eachus, R. E. Graves and M. T. OlmJ. Chem. Phys., Vol. 69, pp. 4580-7 (1978) and Physica Status Solidi A, Vol. 57, 429-37 (1980) and R. S. Eachus and M. T. Olm Annu. Rep. Prog. Chem. Sect. C. Phys. Chem., Vol. 83, 3, pp. 3-48 (1986). The class (ii) dopants employed in the practice of this invention are believed to create such deep electron traps. The thiazole ligands may be substituted with any photographically acceptable substituent which does not prevent incorporation of the dopant into the silver halide grain. Exemplary substituents include lower alkyl (e.g., alkyl groups containing 1-4 carbon atoms), and specifically methyl. A specific example of a substituted thiazole ligand which may be used in accordance with the invention is 5-methylthiazole. The class (ii) dopant preferably is an iridium coordination complex having ligands each of which are more electropositive than a cyano ligand. In a specifically preferred form the remaining non-thiazole or non-substituted-thiazole ligands of the coordination complexes forming class (ii) dopants are halide ligands.

It is specifically contemplated to select class (ii) dopants from among the coordination complexes containing organic ligands disclosed by Olm et al U.S. Patent 5,360,712, Olm et al U.S. Patent 5,457,021 and Kuromoto et al U.S. Patent 5,462,849.

In a preferred form it is contemplated to employ as a class (ii) dopant a hexacoordination complex satisfying the formula: (II) [IrL¹ ₆]^n' wherein

   n' is zero, -1, -2, -3 or -4; and

   L¹₆ represents six bridging ligands which can be independently selected, provided that at least four of the ligands are anionic ligands, each of the ligands is more electropositive than a cyano ligand, and at least one of the ligands comprises a thiazole or substituted thiazole ligand. In a specifically preferred form at least four of the ligands are halide ligands, such as chloride or bromide ligands.

Class (ii) dopant is preferably introduced into the high chloride grains after at least 50 (most preferably 85 and optimally 90) percent of the silver has been precipitated, but before precipitation of the central portion of the grains has been completed. Preferably class (ii) dopant is introduced before 99 (most preferably 97 and optimally 95) percent of the silver has been precipitated. Stated in terms of the fully precipitated grain structure, class (ii) dopant is preferably present in an interior shell region that surrounds at least 50 (most preferably 85 and optimally 90) percent of the silver and, with the more centrally located silver, accounts the entire central portion (99 percent of the silver), most preferably accounts for 97 percent, and optimally accounts for 95 percent of the silver halide forming the high chloride grains. The class (ii) dopant can be distributed throughout the interior shell region delimited above or can be added as one or more bands within the interior shell region.

Class (ii) dopant can be employed in any conventional useful concentration. A preferred concentration range is from 10^-9 to 10^-4 mole per silver mole. Iridium is most preferably employed in a concentration range of from 10^-8 to 10^-5 mole per silver mole.

Specific illustrations of class (ii) dopants are the following: (ii-1)   [IrCl₅(thiazole)]^-2 (ii-2)   [IrCl₄(thiazole)₂]^-1 (ii-3)   [IrBr₅(thiazole)]^-2 (ii-4)   [IrBr₄(thiazole)₂]^-1 (ii-5)   [IrCl₅(5-methylthiazole)]^-2 (ii-6)   [IrCl₄(5-methylthiazole)₂]^-1 (ii-7)   [IrBr₅(5-methylthiazole)]^-2 (ii-8)   [IrBr₄(5-methylthiazole)₂]^-1

In one preferred aspect of the invention in a layer using a magenta dye forming coupler, a class (ii) dopant in combination with an OsCl₅(NO) dopant has been found to produce a preferred result.

Emulsions demonstrating the advantages of the invention can be realized by modifying the precipitation of conventional high chloride silver halide grains having predominantly (>50%) {100} crystal faces by employing a combination of class (i) and (ii) dopants as described above.

The silver halide grains precipitated contain greater than 50 mole percent chloride, based on silver. Preferably the grains contain at least 70 mole percent chloride and, optimally at least 90 mole percent chloride, based on silver. Iodide can be present in the grains up to its solubility limit, which is in silver iodochloride grains, under typical conditions of precipitation, about 11 mole percent, based on silver. It is preferred for most photographic applications to limit iodide to less than 5 mole percent iodide, most preferably less than 2 mole percent iodide, based on silver.

Silver bromide and silver chloride are miscible in all proportions. Hence, any portion, up to 50 mole percent, of the total halide not accounted for chloride and iodide, can be bromide. For color reflection print (i.e., color paper) uses bromide is typically limited to less than 10 mole percent based on silver and iodide is limited to less than 1 mole percent based on silver.

In a widely used form high chloride grains are precipitated to form cubic grains--that is, grains having {100} major faces and edges of equal length. In practice ripening effects usually round the edges and corners of the grains to some extent. However, except under extreme ripening conditions substantially more than 50 percent of total grain surface area is accounted for by {100} crystal faces.

High chloride tetradecahedral grains are a common variant of cubic grains. These grains contain 6 {100} crystal faces and 8 {111} crystal faces. Tetradecahedral grains are within the contemplation of this invention to the extent that greater than 50 percent of total surface area is accounted for by {100} crystal faces.

Although it is common practice to avoid or minimize the incorporation of iodide into high chloride grains employed in color paper, it is has been recently observed that silver iodochloride grains with {100} crystal faces and, in some instances, one or more {111} faces offer exceptional levels of photographic speed. In the these emulsions iodide is incorporated in overall concentrations of from 0.05 to 3.0 mole percent, based on silver, with the grains having a surface shell of greater than 50 Å that is substantially free of iodide and a interior shell having a maximum iodide concentration that surrounds a core accounting for at least 50 percent of total silver. Such grain structures are illustrated by Chen et al EPO 0 718 679.

In another improved form the high chloride grains can take the form of tabular grains having {100} major faces. Preferred high chloride {100} tabular grain emulsions are those in which the tabular grains account for at least 70 (most preferably at least 90) percent of total grain projected area. Preferred high chloride {100} tabular grain emulsions have average aspect ratios of at least 5 (most preferably at least >8). Tabular grains typically have thicknesses of less than 0.3 µm, preferably less than 0.2 µm, and optimally less than 0.07 µm. High chloride {100} tabular grain emulsions and their preparation are disclosed by Maskasky U.S. Patents 5,264,337 and 5,292,632, House et al U.S. Patent 5,320,938, Brust et al U.S. Patent 5,314,798 and Chang et al U.S. Patent 5,413,904.

Once high chloride grains having predominantly {100} crystal faces have been precipitated with a combination of class (i) and class (ii) dopants described above, chemical and spectral sensitization, followed by the addition of conventional addenda to adapt the emulsion for the imaging application of choice can take any convenient conventional form. These conventional features are illustrated by Research Disclosure, Item 38957, cited above, particularly:

• III. Emulsion washing;
• IV. Chemical sensitization;
• V. Spectral sensitization and desensitization;
• VII. Antifoggants and stabilizers;
• VIII. Absorbing and scattering materials;
• IX. Coating and physical property modifying addenda; and
• X. Dye image formers and modifiers.

Some additional silver halide, typically less than 1 percent, based on total silver, can be introduced to facilitate chemical sensitization. It is also recognized that silver halide can be epitaxially deposited at selected sites on a host grain to increase its sensitivity. For example, high chloride {100} tabular grains with corner epitaxy are illustrated by Maskasky U.S. Patent 5,275,930. For the purpose of providing a clear demarcation, the term "silver halide grain" is herein employed to include the silver necessary to form the grain up to the point that the final {100} crystal faces of the grain are formed. Silver halide later deposited that does not overlie the {100} crystal faces previously formed accounting for at least 50 percent of the grain surface area is excluded in determining total silver forming the silver halide grains. Thus, the silver forming selected site epitaxy is not part of the silver halide grains while silver halide that deposits and provides the final {100} crystal faces of the grains is included in the total silver forming the grains, even when it differs significantly in composition from the previously precipitated silver halide.

Image dye-forming couplers may be included in the element such as couplers that form cyan dyes upon reaction with oxidized color developing agents which are described in such representative patents and publications as: U.S. Patent Nos. 2,367,531; 2,423,730; 2,474,293; 2,772,162; 2,895,826; 3,002,836; 3,034,892; 3,041,236; 4,883,746 and "Farbkuppler - Eine Literature Ubersicht," published in Agfa Mitteilungen, Band III, pp. 156-175 (1961). Preferably such couplers are phenols and naphthols that form cyan dyes on reaction with oxidized color developing agent. Also preferable are the cyan couplers described in, for instance, European Patent Application Nos. 491,197; 544,322; 556,700; 556,777; 565,096; 570,006; and 574,948.

Typical cyan couplers are represented by the following formulas:

. For purposes of this invention, an "NB coupler" is a dye-forming coupler which is capable of coupling with the developer 4-amino-3-methyl-N-ethyl-N-(2-methanesulfonamidoethyl) aniline sesquisulfate hydrate to form a dye for which the left bandwidth (LBW) of its absorption spectra upon "spin coating" of a 3% w/v solution of the dye in di-n-butyl sebacate solvent is at least 5 nm. less than the LBW for a 3% w/v solution of the same dye in acetonitrile. The LBW of the spectral curve for a dye is the distance between the left side of the spectral curve and the wavelength of maximum absorption measured at a density of half the maximum.

The "spin coating" sample is prepared by first preparing a solution of the dye in di-n-butyl sebacate solvent (3% w/v). If the dye is insoluble, dissolution is achieved by the addition of some methylene chloride. The solution is filtered and 0.1-0.2ml is applied to a clear polyethylene terephthalate support (approximately 4cm x 4cm) and spun at 4,000RPM using the Spin Coating equipment, Model No. EC101, available from Headway Research Inc., Garland TX. The transmission spectra of the so prepared dye samples are then recorded.

Preferred "NB couplers" form a dye which, in n-butyl sebacate, has a LBW of the absorption spectra upon "spin coating" which is at least 15 nm, preferably at least 25 nm, less than that of the same dye in a 3% solution (w/v) in acetonitrile.

In a preferred embodiment the cyan dye-forming "NB coupler" useful in the invention has the formula (IA)

The coupler of formula (IA) is a 2,5-diamido phenolic cyan coupler wherein the substituents R' and R" are preferably independently selected from unsubstituted or substituted alkyl, aryl, amino, alkoxy and heterocyclyl groups.

In a further preferred embodiment, the "NB coupler" has the formula (I):

Typically, R" is an alkyl, amino or aryl group, suitably a phenyl group. R"' is desirably an alkyl or aryl group or a 5- to 10-membered heterocyclic ring which contains one or more heteroatoms selected from nitrogen, oxygen and sulfur, which ring group is unsubstituted or substituted.

In the preferred embodiment the coupler of formula (I) is a 2,5-diamido phenol in which the 5-amido moiety is an amide of a carboxylic acid which is substituted in the alpha position by a particular sulfone (-SO₂-) group, such as, for example, described in U.S. Patent No. 5,686,235. The sulfone moiety is an unsubstituted or substituted alkylsulfone or a heterocyclyl sulfone or it is an arylsulfone, which is preferably substituted, in particular in the meta and/or para position.

Couplers having these structures of formulae (I) or (IA) comprise cyan dye-forming "NB couplers" which form image dyes having very sharp-cutting dye hues on the short wavelength side of the absorption curves with absorption maxima (λ_max) which are shifted hypsochromically and are generally in the range of 620-645 nm, which is ideally suited for producing excellent color reproduction and high color saturation in color photographic packaging labels.

Referring to formula (I), R₁ and R₂ are independently hydrogen or an unsubstituted or substituted alkyl group, preferably having from 1 to 24 carbon atoms and in particular 1 to 10 carbon atoms, suitably a methyl, ethyl, n-propyl, isopropyl, butyl or decyl group or an alkyl group substituted with one or more fluoro, chloro or bromo atoms, such as a trifluoromethyl group. Suitably, at least one of R₁ and R₂ is a hydrogen atom and if only one of R₁ and R₂ is a hydrogen atom then the other is preferably an alkyl group having 1 to 4 carbon atoms, more preferably one to three carbon atoms and desirably two carbon atoms.

As used herein and throughout the specification unless where specifically stated otherwise, the term "alkyl" refers to an unsaturated or saturated straight or branched chain alkyl group, including alkenyl, and includes aralkyl and cyclic alkyl groups, including cycloalkenyl, having 3-8 carbon atoms and the term ' aryl' includes specifically fused aryl.

In formula (I), R" is suitably an unsubstituted or substituted amino, alkyl or aryl group or a 5-10 membered heterocyclic ring which contains one or more heteroatoms selected from nitrogen, oxygen and sulfur, which ring is unsubstituted or substituted, but is more suitably an unsubstituted or substituted phenyl group.

Examples of suitable substituent groups for this aryl or heterocyclic ring include cyano, chloro, fluoro, bromo, iodo, alkyl- or aryl-carbonyl, alkyl- or aryl-oxycarbonyl, carbonamido, alkyl- or aryl-carbonamido, alkyl- or arylsulfonyl, alkyl- or aryl-sulfonyloxy, alkyl- or aryl-oxysulfonyl, alkyl- or arylsulfoxide, alkyl- or aryl-sulfamoyl, alkyl- or aryl-sulfonamido, aryl, alkyl, alkoxy, aryloxy, nitro, alkyl- or aryl-ureido and alkyl- or aryl-carbamoyl groups, any of which may be further substituted. Preferred groups are halogen, cyano, alkoxycarbonyl, alkylsulfamoyl, alkyl-sulfonamido, alkylsulfonyl, carbamoyl, alkylcarbamoyl or alkylcarbonamido. Suitably, R" is a 4-chlorophenyl, 3,4-di-chlorophenyl, 3,4-difluorophenyl, 4-cyanophenyl, 3-chloro-4-cyanophenyl, pentafluorophenyl, or a 3- or 4-sulfonamidophenyl group.

In formula (I), when R"' is alkyl it may be unsubstituted or substituted with a substituent such as halogen or alkoxy. When R"' is aryl or a heterocycle, it may be substituted. Desirably it is not substituted in the position alpha to the sulfonyl group.

In formula (I), when R"' is a phenyl group, it may be substituted in the meta and/or para positions with one to three substituents independently selected from the group consisting of halogen, and unsubstituted or substituted alkyl, alkoxy, aryloxy, acyloxy, acylamino, alkyl- or aryl-sulfonyloxy, alkyl- or aryl-sulfamoyl, alkyl- or aryl-sulfamoylamino, alkyl- or aryl-sulfonamido, alkyl-or aryl-ureido, alkyl- or aryl-oxycarbonyl, alkyl- or aryl-oxy-carbonylamino and alkyl- or aryl-carbamoyl groups.

In particular each substituent may be an alkyl group such as methyl, t-butyl, heptyl, dodecyl, pentadecyl, octadecyl or 1,1,2,2-tetramethylpropyl; an alkoxy group such as methoxy, t-butoxy, octyloxy, dodecyloxy, tetradecyloxy, hexadecyloxy or octadecyloxy; an aryloxy group such as phenoxy, 4-t-butylphenoxy or 4-dodecyl-phenoxy; an alkyl- or aryl-acyloxy group such as acetoxy or dodecanoyloxy; an alkyl- or aryl-acylamino group such as acetamido, hexadecanamido or benzamido; an alkyl- or aryl-sulfonyloxy group such as methyl-sulfonyloxy, dodecylsulfonyloxy or 4-methylphenyl-sulfonyloxy; an alkyl- or aryl-sulfamoyl-group such as N-butylsulfamoyl or N-4-t-butylphenylsulfamoyl; an alkyl- or aryl-sulfamoylamino group such as N-butyl-sulfamoylamino or N-4-t-butylphenylsulfamoyl-amino; an alkyl- or aryl-sulfonamido group such as methane-sulfonamido, hexadecanesulfonamido or 4-chlorophenyl-sulfonamido; an alkyl- or aryl-ureido group such as methylureido or phenylureido; an alkoxy- or aryloxy-carbonyl such as methoxycarbonyl or phenoxycarbonyl; an alkoxy- or aryloxy-carbonylamino group such as methoxy-carbonylamino or phenoxycarbonylamino; an alkyl- or aryl-carbamoyl group such as N-butylcarbamoyl or N-methyl-N-dodecylcarbamoyl; or a perfluoroalkyl group such as trifluoromethyl or heptafluoropropyl.

Suitably the above substituent groups have 1 to 30 carbon atoms, more preferably 8 to 20 aliphatic carbon atoms. A desirable substituent is an alkyl group of 12 to 18 aliphatic carbon atoms such as dodecyl, pentadecyl or octadecyl or an alkoxy group with 8 to 18 aliphatic carbon atoms such as dodecyloxy and hexadecyloxy or a halogen such as a meta or para chloro group, carboxy or sulfonamido. Any such groups may contain interrupting heteroatoms such as oxygen to form e.g. polyalkylene oxides.

In formula (I) or (IA) Z is a hydrogen atom or a group which can be split off by the reaction of the coupler with an oxidized color developing agent, known in the photographic art as a 'coupling-off group' and may preferably be hydrogen, chloro, fluoro, substituted aryloxy or mercaptotetrazole, more preferably hydrogen or chloro.

The presence or absence of such groups determines the chemical equivalency of the coupler, i.e., whether it is a 2-equivalent or 4-equivalent coupler, and its particular identity can modify the reactivity of the coupler. Such groups can advantageously affect the layer in which the coupler is coated, or other layers in the photographic recording material, by performing, after release from the coupler, functions such as dye formation, dye hue adjustment, development acceleration or inhibition, bleach acceleration or inhibition, electron transfer facilitation, color correction, and the like.

Representative classes of such coupling-off groups include, for example, halogen, alkoxy, aryloxy, heterocyclyloxy, sulfonyloxy, acyloxy, acyl, heterocyclylsulfonamido, heterocyclylthio, benzothiazolyl, phosophonyloxy, alkylthio, arylthio, and arylazo. These coupling-off groups are described in the art, for example, in U.S. Patent Nos. 2,455,169; 3,227,551; 3,432,521; 3,467,563; 3,617,291; 3,880,661; 4,052,212; and 4,134,766; and in U.K. Patent Nos. and published applications 1,466,728; 1,531,927; 1,533,039; 2,066,755A, and 2,017,704A. Halogen, alkoxy and aryloxy groups are most suitable.

Examples of specific coupling-off groups are -Cl, -F, -Br, -SCN,-OCH₃, -OC₆H₅, -OCH₂C(=O)NHCH₂CH₂OH, -OCH₂C(O)NHCH₂CH₂OCH₃, -OCH₂C(O)NHCH₂CH₂OC(=O)OCH₃, -P(=O)(OC₂H₅)₂, -SCH₂CH₂COOH,

Typically, the coupling-off group is a chlorine atom, hydrogen atom or p-methoxyphenoxy group.

It is essential that the substituent groups be selected so as to adequately ballast the coupler and the resulting dye in the organic solvent in which the coupler is dispersed. The ballasting may be accomplished by providing hydrophobic substituent groups in one or more of the substituent groups. Generally a ballast group is an organic radical of such size and configuration as to confer on the coupler molecule sufficient bulk and aqueous insolubility as to render the coupler substantially nondiffusible from the layer in which it is coated in a photographic element. Thus, the combination of substituent are suitably chosen to meet these criteria. To be effective, the ballast will usually contain at least 8 carbon atoms and typically contains 10 to 30 carbon atoms. Suitable ballasting may also be accomplished by providing a plurality of groups which in combination meet these criteria. In the preferred embodiments of the invention R₁ in formula (I) is a small alkyl group or hydrogen. Therefore, in these embodiments the ballast would be primarily located as part of the other groups. Furthermore, even if the coupling-off group Z contains a ballast it is often necessary to ballast the other substituents as well, since Z is eliminated from the molecule upon coupling; thus, the ballast is most advantageously provided as part of groups other than Z.

The following examples further illustrate preferred coupler of the invention. It is not to be construed that the present invention is limited to these examples.

Preferred couplers are IC-3, IC-7, IC-35, and IC-36 because of their suitably narrow left bandwidths.

Couplers that form magenta dyes upon reaction with oxidized color developing agent are described in such representative patents and publications as: U.S. Patent Nos. 2,311,082; 2,343,703; 2,369,489; 2,600,788; 2,908,573; 3,062,653; 3,152,896; 3,519,429; 3,758,309, and "Farbkuppler-eine Literature Ubersicht," published in Agfa Mitteilungen, Band III, pp. 126-156 (1961). Preferably such couplers are pyrazolones, pyrazolotriazoles, or pyrazolobenzimidazoles that form magenta dyes upon reaction with oxidized color developing agents. Especially preferred couplers are 1H-pyrazolo [5,1-c]-1,2,4-triazole and 1H-pyrazolo [1,5-b]-1,2,4-triazole. Examples of 1H-pyrazolo [5,1-c]-1,2,4-triazole couplers are described in U.K. Patent Nos. 1,247,493; 1,252,418; 1,398,979; U.S. Patent Nos. 4,443,536; 4,514,490; 4,540,654; 4,590,153; 4,665,015; 4,822,730; 4,945,034; 5,017,465; and 5,023,170. Examples of 1H-pyrazolo [1,5-b]-1,2,4-triazoles can be found in European Patent applications 176,804; 177,765; U.S Patent Nos. 4,659,652; 5,066,575; and 5,250,400.

Typical pyrazoloazole and pyrazolone couplers are represented by the following formulas:

Specific examples of such couplers are:

Couplers that form yellow dyes upon reaction with oxidized color developing agent are described in such representative patents and publications as: U.S. Patent Nos. 2,298,443; 2,407,210; 2,875,057; 3,048,194; 3,265,506; 3,447,928; 3,960,570; 4,022,620; 4,443,536; 4,910,126; and 5,340,703 and "Farbkuppler-eine Literature Ubersicht," published in Agfa Mitteilungen, Band III, pp. 112-126 (1961). Such couplers are typically open chain ketomethylene compounds. Also preferred are yellow couplers such as described in, for example, European Patent Application Nos. 482,552; 510,535; 524,540; 543,367; and U.S. Patent No. 5,238,803. For improved color reproduction, couplers which give yellow dyes that cut off sharply on the long wavelength side are particularly preferred (for example, see U.S. Patent No. 5,360,713).

Typical preferred yellow couplers are represented by the following formulas:

Preferred yellow couplers can be of the following general structures

Unless otherwise specifically stated, substituent groups which may be substituted on molecules herein include any groups, whether substituted or unsubstituted, which do not destroy properties necessary for photographic utility. When the term "group" is applied to the identification of a substituent containing a substitutable hydrogen, it is intended to encompass not only the substituent's unsubstituted form, but also its form further substituted with any group or groups as herein mentioned. Suitably, the group may be halogen or may be bonded to the remainder of the molecule by an atom of carbon, silicon, oxygen, nitrogen, phosphorous, or sulfur. The substituent may be, for example, halogen, such as chlorine, bromine or fluorine; nitro; hydroxyl; cyano; carboxyl; or groups which may be further substituted, such as alkyl, including straight or branched chain alkyl, such as methyl, trifluoromethyl, ethyl, t-butyl, 3-(2,4-di-t-pentylphenoxy) propyl, and tetradecyl; alkenyl, such as ethylene, 2-butene; alkoxy, such as methoxy, ethoxy, propoxy, butoxy, 2-methoxyethoxy, sec-butoxy, hexyloxy, 2-ethylhexyloxy, tetradecyloxy, 2-(2,4-di-t-pentylphenoxy)ethoxy, and 2-dodecyloxyethoxy; aryl such as phenyl, 4-t-butylphenyl, 2,4,6-trimethylphenyl, naphthyl; aryloxy, such as phenoxy, 2-methylphenoxy, alpha- or beta-naphthyloxy, and 4-tolyloxy; carbonamido, such as acetamido, benzamido, butyramido, tetradecanamido, alpha-(2,4-di-t-pentyl-phenoxy)acetamido, alpha-(2,4-di-t-pentylphenoxy)butyramido, alpha-(3-pentadecylphenoxy)-hexanamido, alpha-(4-hydroxy-3-t-butylphenoxy)-tetradecanamido, 2-oxo-pyrrolidin-1-yl, 2-oxo-5-tetradecylpyrrolin-l-yl, N-methyltetradecanamido, N-succinimido, N-phthalimido, 2,5-dioxo-1-oxazolidinyl, 3-dodecyl-2,5-dioxo-1-imidazolyl, and N-acetyl-N-dodecylamino, ethoxycarbonylamino, phenoxycarbonylamino, benzyloxycarbonylamino, hexadecyloxycarbonylamino, 2,4-di-t-butylphenoxycarbonylamino, phenylcarbonylamino, 2,5-(di-t-pentylphenyl)carbonylamino,p-dodecyl-phenylcarbonylamino, p-toluylcarbonylamino, N-methylureido, N,N-dimethylureido, N-methyl-N-dodecylureido, N-hexadecylureido, N,N-dioctadecylureido, N,N-dioctyl-N'-ethylureido, N-phenylureido, N,N-diphenylureido, N-phenyl-N-p-toluylureido, N-(m-hexadecylphenyl)ureido, N,N-(2,5-di-t-pentylphenyl)-N'-ethylureido, and t-butylcarbonamido; sulfonamido, such as methylsulfonamido, benzenesulfonamido, p-toluylsulfonamido, p-dodecylbenzenesulfonamido, N-methyltetradecylsulfonamido, N,N-dipropyl-sulfamoylamino, and hexadecylsulfonamido; sulfamoyl, such as N-methylsulfamoyl, N-ethylsulfamoyl, N,N-dipropylsulfamoyl, N-hexadecylsulfamoyl, N,N-dimethylsulfamoyl; N-[3-(dodecyloxy)propyl]sulfamoyl, N-[4-(2,4-di-t-pentylphenoxy)butyl]sulfamoyl, N-methyl-N-tetradecylsulfamoyl, and N-dodecylsulfamoyl; carbamoyl, such as N-methylcarbamoyl, N,N-dibutylcarbamoyl, N-octadecylcarbamoyl, N-[4-(2,4-di-t-pentylphenoxy)butyl]carbamoyl, N-methyl-N-tetradecylcarbamoyl, and N,N-dioctylcarbamoyl; acyl, such as acetyl, (2,4-di-t-amylphenoxy)acetyl, phenoxycarbonyl, p-dodecyloxyphenoxycarbonyl, methoxycarbonyl, butoxycarbonyl, tetradecyloxycarbonyl, ethoxycarbonyl, benzyloxycarbonyl, 3-pentadecyloxycarbonyl, and dodecyloxycarbonyl; sulfonyl, such as methoxysulfonyl, octyloxysulfonyl, tetradecyloxysulfonyl, 2-ethylhexyloxysulfonyl, phenoxysulfonyl, 2,4-di-t-pentylphenoxysulfonyl, methylsulfonyl, octylsulfonyl, 2-ethylhexylsulfonyl, dodecylsulfonyl, hexadecylsulfonyl, phenylsulfonyl, 4-nonylphenylsulfonyl, and p-toluylsulfonyl; sulfonyloxy, such as dodecylsulfonyloxy, and hexadecylsulfonyloxy; sulfinyl, such as methylsulfinyl, octylsulfinyl, 2-ethylhexylsulfinyl, dodecylsulfinyl, hexadecylsulfinyl, phenylsulfinyl, 4-nonylphenylsulfinyl, and p-toluylsulfinyl; thio, such as ethylthio, octylthio, benzylthio, tetradecylthio, 2-(2,4-di-t pentylphenoxy)ethylthio, phenylthio, 2-butoxy-5-t-octylphenylthio, and p-tolylthio; acyloxy, such as acetyloxy, benzoyloxy, octadecanoyloxy, p-dodecylamidobenzoyloxy, N-phenylcarbamoyloxy, N-ethylcarbamoyloxy, and cyclohexylcarbonyloxy; amino, such as phenylanilino, 2-chloroanilino, diethylamino, dodecylamino; imino, such as 1 (N-phenylimido)ethyl, N-succinimido or 3-benzylhydantoinyl; phosphate, such as dimethylphosphate and ethylbutylphosphate; phosphite, such as diethyl and dihexylphosphite; a heterocyclic group, a heterocyclic oxy group or a heterocyclic thio group, each of which may be substituted and which contain a 3- to 7-membered heterocyclic ring composed of carbon atoms and at least one hetero atom selected from the group consisting of oxygen, nitrogen and sulfur, such as 2-furyl, 2-thienyl, 2-benzimidazolyloxy or 2-benzothiazolyl; quaternary ammonium, such as triethylammonium; and silyloxy, such as trimethylsilyloxy.

If desired, the substituents may themselves be further substituted one or more times with the described substituent groups. The particular substituents used may be selected by those skilled in the art to attain the desired photographic properties for a specific application and can include, for example, hydrophobic groups, solubilizing groups, blocking groups, releasing or releasable groups, etc. Generally, the above groups and substituents thereof may include those having up to 48 carbon atoms, typically 1 to 36 carbon atoms and usually less than 24 carbon atoms, but greater numbers are possible depending on the particular substituents selected.

Representative substituents on ballast groups include alkyl, aryl, alkoxy, aryloxy, alkylthio, hydroxy, halogen, alkoxycarbonyl, aryloxcarbonyl, carboxy, acyl, acyloxy, amino, anilino, carbonamido, carbamoyl, alkylsulfonyl, arylsulfonyl, sulfonamido, and sulfamoyl groups wherein the substituents typically contain 1 to 42 carbon atoms. Such substituents can also be further substituted.

Silver halide imaging layers substantially free of stabilizers are preferred. Silver halide stabilizers are typically utilized to protect from the growth of fog in storage and to reduce image fading. Stabilizers are however expensive and not generally required for silver halide images attached to packages of the invention since the shelf life of a package tends to be less than one calendar year. Silver halide imaging layers substantially free of stabilizers would be low in cost and have acceptable image quality for images attached to packages.

Stabilizers and scavengers that can be used in these photographic elements, but are not limited to, the following.

Examples of solvents which may be used in the invention include the following: Tritolyl phosphate S-1 Dibutyl phthalate S-2 Diundecyl phthalate S-3 N,N-Diethyldodecanamide S-4 N,N-Dibutyldodecanamide S-5 Tris(2-ethylhexyl)phosphate S-6 Acetyl tributyl citrate S-7 2,4-Di-tert-pentylphenol S-8 2-(2-Butoxyethoxy)ethyl acetate S-9 1,4-Cyclohexyldimethylene bis(2-ethylhexanoate) S-10

The dispersions used in photographic elements may also include ultraviolet (UV) stabilizers and so called liquid UV stabilizers such as described in U.S. Patent Nos. 4,992,358; 4,975,360; and 4,587,346. Examples of UV stabilizers are shown below.

The aqueous phase may include surfactants. Surfactant may be cationic, anionic, zwitterionic or non-ionic. Useful surfactants include, but are not limited to, the following.

Further, it is contemplated to stabilize photographic dispersions prone to particle growth through the use of hydrophobic, photographically inert compounds such as disclosed by Zengerle et al in U.S. Patent 5,468,604.

In a preferred embodiment the invention employs recording elements which are constructed to contain at least three silver halide emulsion layer units. A suitable full color, multilayer format for a recording element used in the invention is represented by Structure I.

Conventional features that can be incorporated into multilayer (and particularly multicolor) recording elements contemplated for use in the method of the invention are illustrated by Research Disclosure, Item 38957, cited above:

• XI. Layers and layer arrangements
• XII. Features applicable only to color negative
• XIII. Features applicable only to color positive
  • B. Color reversal
  • C. Color positives derived from color negatives
• XIV. Scan facilitating features.

The recording elements comprising the radiation sensitive high chloride emulsion layers according to this invention can be conventionally optically printed, or in accordance with a particular embodiment of the invention can be image-wise exposed in a pixel-by-pixel mode using suitable high energy radiation sources typically employed in electronic printing methods. Suitable actinic forms of energy encompass the ultraviolet, visible and infrared regions of the electromagnetic spectrum as well as electron-beam radiation and is conveniently supplied by beams from one or more light emitting diodes or lasers, including gaseous or solid state lasers. Exposures can be monochromatic, orthochromatic or panchromatic. For example, when the recording element is a multilayer multicolor element, exposure can be provided by laser or light emitting diode beams of appropriate spectral radiation, for example, infrared, red, green or blue wavelengths, to which such element is sensitive. Multicolor elements can be employed which produce cyan, magenta and yellow dyes as a function of exposure in separate portions of the electromagnetic spectrum, including at least two portions of the infrared region, as disclosed in the previously mentioned U.S. Patent No. 4,619,892. Suitable exposures include those up to 2000 nm, preferably up to 1500 nm. Suitable light emitting diodes and commercially available laser sources are known and commercially available. Imagewise exposures at ambient, elevated or reduced temperatures and/or pressures can be employed within the useful response range of the recording element determined by conventional sensitometric techniques, as illustrated by T.H. James, The Theory of the Photographic Process, 4th Ed., Macmillan, 1977, Chapters 4, 6, 17, 18 and 23.

It has been observed that anionic [MX_xY_yL_z] hexacoordination complexes, where M is a group 8 or 9 metal (preferably iron, ruthenium or iridium), X is halide or pseudohalide (preferably Cl, Br or CN) x is 3 to 5, Y is H₂O, y is 0 or 1, L is a C-C, H-C or C-N-H organic ligand, and Z is 1 or 2, are surprisingly effective in reducing high intensity reciprocity failure (HIRF), low intensity reciprocity failure (LIRF) and thermal sensitivity variance and in in improving latent image keeping (LIK). As herein employed HIRF is a measure of the variance of photographic properties for equal exposures, but with exposure times ranging from 10^-1 to 10^-6 second. LIRF is a measure of the variance of photographic properties for equal exposures, but with exposure times ranging from 10^-1 to 100 seconds. Although these advantages can be generally compatible with face centered cubic lattice grain structures, the most striking improvements have been observed in high (>50 mole %, preferably ≥90 mole %) chloride emulsions. Preferred C-C, H-C or C-N-H organic ligands are aromatic heterocycles of the type described in U.S. Pat. No. 5,462,849. The most effective C-C, H-C or C-N-H organic ligands are azoles and azines, either unsustituted or containing alkyl, alkoxy or halide substituents, where the alkyl moieties contain from 1 to 8 carbon atoms. Particularly preferred azoles and azines include thiazoles, thiazolines and pyrazines.

The quantity or level of high energy actinic radiation provided to the recording medium by the exposure source is generally at least 10^-4 ergs/cm², typically in the range of about 10^-4 ergs/cm² to 10^-3 ergs/cm² and often from 10^-3 ergs/cm² to 10² ergs/cm². Exposure of the recording element in a pixel-by-pixel mode as known in the prior art persists for only a very short duration or time. Typical maximum exposure times are up to 100 µ seconds, often up to 10 µ seconds, and frequently up to only 0.5 µ seconds. Single or multiple exposures of each pixel are contemplated. The pixel density is subject to wide variation, as is obvious to those skilled in the art. The higher the pixel density, the sharper the images can be, but at the expense of equipment complexity. In general, pixel densities used in conventional electronic printing methods of the type described herein do not exceed 10⁷ pixels/cm² and are typically in the range of about 10⁴ to 10⁶ pixels/cm². An assessment of the technology of high-quality, continuous-tone, color electronic printing using silver halide photographic paper which discusses various features and components of the system, including exposure source, exposure time, exposure level and pixel density and other recording element characteristics is provided in Firth et al., A Continuous-Tone Laser Color Printer, Journal of Imaging Technology, Vol. 14, No. 3, June 1988, which is hereby incorporated herein by reference. As previously indicated herein, a description of some of the details of conventional electronic printing methods comprising scanning a recording element with high energy beams such as light emitting diodes or laser beams, are set forth in Hioki U.S. Patent 5,126,235, European Patent Applications 479 167 A1 and 502 508 Al.

Once imagewise exposed, the recording elements can be processed in any convenient conventional manner to obtain a viewable image. Such processing is illustrated by Research Disclosure, Item 38957, cited above:

• XVIII. Chemical development systems
• XIX. Development
• XX. Desilvering, washing, rinsing and stabilizing

In addition, a useful developer for the inventive material is a homogeneous, single part developing agent. The homogeneous, single-part color developing concentrate is prepared using a critical sequence of steps:

In the first step, an aqueous solution of a suitable color developing agent is prepared. This color developing agent is generally in the form of a sulfate salt. Other components of the solution can include an antioxidant for the color developing agent, a suitable number of alkali metal ions (in an at least stoichiometric proportion to the sulfate ions) provided by an alkali metal base, and a photographically inactive water-miscible or water-soluble hydroxy-containing organic solvent. This solvent is present in the final concentrate at a concentration such that the weight ratio of water to the organic solvent is from about 15:85 to about 50:50.

In this environment, especially at high alkalinity, alkali metal ions and sulfate ions form a sulfate salt that is precipitated in the presence of the hydroxy-containing organic solvent. The precipitated sulfate salt can then be readily removed using any suitable liquid/solid phase separation technique (including filtration, centrifugation or decantation). If the antioxidant is a liquid organic compound, two phases may be formed and the precipitate may be removed by discarding the aqueous phase.

The color developing concentrates of this invention include one or more color developing agents that are well known in the art that, in oxidized form, will react with dye forming color couplers in the processed materials. Such color developing agents include, but are not limited to, aminophenols, p-phenylenediamines (especially N,N-dialkyl-p-phenylenediamines) and others which are well known in the art, such as EP 0 434 097 A1 (published June 26, 1991) and EP 0 530 921 A1 (published March 10, 1993). It may be useful for the color developing agents to have one or more water-solubilizing groups as are known in the art. Further details of such materials are provided in Research Disclosure, publication 38957, pages 592-639 (September 1996). Research Disclosure is a publication of Kenneth Mason Publications Ltd., Dudley House, 12 North Street, Emsworth, Hampshire PO10 7DQ England (also available from Emsworth Design Inc., 121 West 19th Street, New York, N.Y. 10011). This reference will be referred to hereinafter as "Research Disclosure".

Preferred color developing agents include, but are not limited to, N,N-diethyl p-phenylenediamine sulfate (KODAK Color Developing Agent CD-2), 4-amino-3-methyl-N-(2-methane sulfonamidoethyl)aniline sulfate, 4-(N-ethyl-N-β-hydroxyethylamino)-2-methylaniline sulfate (KODAK Color Developing Agent CD-4), p-hydroxyethylethylaminoaniline sulfate, 4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamine sesquisulfate (KODAK Color Developing Agent CD-3), 4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamine sesquisulfate, and others readily apparent to one skilled in the art.

In order to protect the color developing agents from oxidation, one or more antioxidants are generally included in the color developing compositions. Either inorganic or organic antioxidants can be used. Many classes of useful antioxidants are known, including but not limited to, sulfites (such as sodium sulfite, potassium sulfite, sodium bisulfite and potassium metabisulfite), hydroxylamine (and derivatives thereof), hydrazines, hydrazides, amino acids, ascorbic acid (and derivatives thereof), hydroxamic acids, aminoketones, mono-and polysaccharides, mono- and polyamines, quaternary ammonium salts, nitroxy radicals, alcohols, and oximes. Also useful as antioxidants are 1,4-cyclohexadiones. Mixtures of compounds from the same or different classes of antioxidants can also be used if desired.

Especially useful antioxidants are hydroxylamine derivatives as described for example, in US Patents 4,892,804; 4,876,174; 5,354,646; and 5,660,974, and US 5,646,327 (Burns et al). Many of these antioxidants are mono-and dialkylhydroxylamines having one or more substituents on one or both alkyl groups. Particularly useful alkyl substituents include sulfo, carboxy, amino, sulfonamido, carbonamido, hydroxy and other solubilizing substituents.

More preferably, the noted hydroxylamine derivatives can be mono- or dialkylhydroxylamines having one or more hydroxy substituents on the one or more alkyl groups. Representative compounds of this type are described for example in US Patent 5,709,982 (Marrese et al)as having the structure I:

X₁ is -CR₂(OH)CHR₁- and X₂ is -CHR₁CR₂(OH)- wherein R₁ and R₂ are independently hydrogen, hydroxy, a substituted or unsubstituted alkyl group or 1 or 2 carbon atoms, a substituted or unsubstituted hydroxyalkyl group of 1 or 2 carbon atoms, or R₁ and R₂ together represent the carbon atoms necessary to complete a substituted or unsubstituted 5- to 8-membered saturated or unsaturated carbocyclic ring structure.

Y is a substituted or unsubstituted alkylene group having at least 4 carbon atoms, and has an even number of carbon atoms, or Y is a substituted or unsubstituted divalent aliphatic group having an even total number of carbon and oxygen atoms in the chain, provided that the aliphatic group has a least 4 atoms in the chain.

Also in Structure I, m, n and p are independently 0 or 1. Preferably, each of m and n is 1, and p is 0.

Specific di-substituted hydroxylamine antioxidants include, but are not limited to: N,N-bis(2,3-dihydroxypropyl)hydroxylamine, N,N-bis(2-methyl-2,3-dihydroxypropyl)hydroxylamine and N,N-bis(1-hydroxymethyl-2-hydroxy-3-phenylpropyl)hydroxylamine. The first compound is preferred.

The colorants can be incorporated into the imaging element by direct addition of the colorant to a coating melt by mixing the colorant with an aqueous medium containing gelatin (or other hydrophilic colloid) at a temperature of 40°C or higher. The colorant can also be mixed with an aqueous solution of a water-soluble or water-dispersible surfactant or polymer, and passing the premix through a mill until the desired particle size is obtained. The mill can be any high energy device such as a colloid mill, high pressure homogenizer, or the like.

The preferred color of the pigment is blue as a blue pigment incorporated into a gelatin layer offsets the native yellowness of the gelatin yielding a neutral background for the image layers.

Suitable pigments used in this invention can be any inorganic or organic, colored materials which are practically insoluble in the medium in which they are incorporated. The preferred pigments are organic, and are those described in Industrial Organic Pigments: Production, Properties, Applications by W. Herbst and K. Hunger, 1993, Wiley Publishers. These include: Azo Pigments such as monoazo yellow and orange, diazo, naphthol, naphthol reds, azo lakes, benzimidazolone, disazo condensation, metal complex, isoindolinone and isoindoline, Polycyclic Pigments such as phthalocyanine, quinacridone, perylene, perinone, diketopyrrolo pyrrole and thioindigo, and Anthrquinone Pigments such as anthrapyrimidine, flavanthrone, pyranthrone, anthanthrone, dioxazine, triarylcarbodium and quinophthalone.

The most preferred pigments are the anthraquinones such as Pigment Blue 60, phthalocyanines such as Pigment Blue 15, 15:1, 15:3, 15:4 and 15:6, and quinacridones such as Pigment Red 122 , as listed in NPIRI Raw Materials Data Handbook, Vol. 4, Pigments, 1983, National Printing Research Institute. These pigments have a dye hue sufficient to overcome the native yellowness of the gelatin imaging layer and are easily dispersed in a aqueous solution.

An aqueous dispersion of the pigments is preferred because the preferred pigments are insoluble in most, if not all, organic solvents, and therefore a high quality dispersion is not likely in a solvent system. In fact, the only solvent that will dissolve preferred pigments PR-122 and PB-15 is concentrated sulfuric acid, which is not an organic solvent. Preferred pigments of the invention are by nature, insoluble, crystalline solids, which is the most thermodynamically stable form that they can assume. In an oil and water dispersion, they would be in the form of an amorphous solid, which is thermodynamically unstable. Therefore, one would have to worry about the pigment eventually converting to the crystalline form with age. We might as well start with a crystalline solid and not worry about preventing the phase transition. Another reason to avoid solvent pigment dispersions is that the high boiling solvent is not removed with evaporation, and it could cause unwanted interactions in the coating melt such as ripening of DOH dispersion particles, or equilibration with other layers, if it was used in the coating. The use of solid particle dispersion avoids organic solvents altogether.

In the preferred embodiment, the colorant is dispersed in the binder in the form of a solid particle dispersion. Such dispersions are formed by first mixing the colorant with an aqueous solution containing a water-soluble or water-dispersible surfactant or polymer to form a coarse aqueous premix, and adding the premix to a mill. The amount of water-soluble or water-dispersible surfactant or polymer can vary over a wide range, but is generally in the range of 0.01% to 100% by weight of polymer, preferably about 0.3% to about 60%, and more preferably 0.5% to 50%, the percentages being by weight of polymer, based on the weight of the colorant useful in imaging.

The mill can be for example, a ball mill, media mill, attritor mill, vibratory mill or the like. The mill is charged with the appropriate milling media such as, for example, beads of silica, silicon nitride, sand, zirconium oxide, yttria-stabilized zirconium oxide, alumina, titanium, glass, polystyrene, etc. The bead sizes typically range from 0.25 to 3.0 mm in diameter, but smaller media can be used if desired. The premix is milled until the desired particle size range is reached.

The solid colorant particles are subjected to repeated collisions with the milling media, resulting in crystal fracture, deagglomeration, and consequent particle size reduction. The solid particle dispersions of the colorant should have a final average particle size of less than 1 µm, preferably less than 0.1 µm, and most preferably between 0.01 and 0.1 µm. Most preferably, the solid colorant particles are of sub-micrometer average size. Solid particle size between 0.01 and 0.1 provides the best pigment utilization and had a reduction in unwanted light absorption compared to pigments with a particle size greater than 1.2 µm.

Surfactants, polymers, and other additional conventional addenda may also be used in the dispersing process described herein in accordance with prior art solid particle dispersing procedures. Such surfactants, polymers and other addenda are disclosed in U.S. Patent Nos. 5,468,598; 5,300,394; 5,278,037; 4,006,025; 4,924,916; 4,294,917; 4,940,654; 4,950,586; 4,927,744; 5,279,931; 5,158,863; 5,135,844; 5,091,296; 5,089,380; 5,103,640; 4,990,431; 4,970,139; 5,256,527; 5,089,380; 5,103,640; 4,990,431; 4,970,139; 5,256,527; 5,015,564; 5,008,179; 4,957,857; and 2,870,012, British Patent specifications 1,570,362 and 1,131,179.

Additional surfactants or other water soluble polymers may be added after formation of the colorant dispersion, before or after subsequent addition of the colorant dispersion to an aqueous coating medium for coating onto a polymer base. The aqueous medium preferably contains other compounds such as stabilizers and dispersants, for example, additional anionic, nonionic, zwitterionic, or cationic surfactants, and water soluble binders such as gelatin as is well known in the imaging art. The aqueous coating medium may further contain other dispersions or emulsions of compounds useful in imaging.

The following examples illustrate the practice of this invention. They are not intended to be exhaustive of all possible variations of the invention. Parts and percentages are by weight unless otherwise indicated.

In this example a reflective two-sided silver halide image was created by coating light sensitive silver halide imaging layers on a flexible, transparent polyester base that contained an integral polyethylene layer used to promote silver halide emulsion to the flexible, transparent polymer base. After processing the image, the developed silver halide images were folded around a reflective polymer planer partitioning member. The developed silver halide images were adhered to the planer partitioning member utilizing an acrylic based pressure sensitive adhesive. This example will demonstrate a superior two-sided image compared to prior art methods of post process adhesion of two photographs together. Further, this example will show that by printing and developing the silver halide images on a transparent sheet, improvements in image sharpness, image durability and processing efficiency will be obvious.

A oriented polyethylene terephthalate transparent sheet with a thickness of 37 micrometers. The polyethylene terephthalate base had a stiffness of 15 millinewtons in the machine direction and 20 millinewtons in the cross direction. The polyester sheet had an optical transmission of 96%. The transparent polyester sheet had a integral emulsion adhesion layer comprising a low density polyethylene (d=0.910 g/cc) skin layer one each side that was 1 micrometer thick. The polyethylene skin layers were treated with a corona discharge prior to silver halide coating.

A oriented three layer composite sheet polyolefin sheet (56 micrometers thick) (d = 0.68 g/cc) consisting of a microvoided and oriented polypropylene core (approximately 30% of the total sheet thickness), with a homopolymer non-microvoided oriented polypropylene layer on each side of the voided layer; the void initiating material used was poly(butylene terephthalate). The polypropylene layers adjacent the voided layers contained TiO₂, optical brightener and blue tint to offset the native yellowness of the gelatin used in the silver halide imaging layers.

Silver chloride emulsions were chemically and spectrally sensitized as described below. A biocide comprising a mixture of N-methyl-isothiazolone and N-methyl-5-chloro-isthiazolone was added after sensitization.

A high chloride silver halide emulsion is precipitated by adding approximately equimolar silver nitrate and sodium chloride solutions into a well stirred reactor containing glutaryldiaminophenyldisulfide, gelatin peptizer and thioether ripener. Cesium pentachloronitrosylosmate(II) dopant is added during the silver halide grain formation for most of the precipitation, followed by the addition of potassium hexacyanoruthenate(II), potassium (5-methylthiazole)-pentachloroiridate, a small amount of KI solution, and shelling without any dopant. The resultant emulsion contains cubic shaped grains having edge length of 0.6 µm. The emulsion is optimally sensitized by the addition of a colloidal suspension of aurous sulfide and heat ramped to 60°C during which time blue sensitizing dye BSD-4, potassium hexchloroiridate, Lippmann bromide and 1-(3-acetamidophenyl)-5-mercaptotetrazole were added.

A high chloride silver halide emulsion is precipitated by adding approximately equimolar silver nitrate and sodium chloride solutions into a well stirred reactor containing, gelatin peptizer and thioether ripener. Cesium pentachloronitrosylosmate(II) dopant is added during the silver halide grain formation for most of the precipitation, followed by the addition of potassium (5-methylthiazole)-pentachloroiridate. The resultant emulsion contains cubic shaped grains of 0.3µm in edgelength size. The emulsion is optimally sensitized by the addition of glutaryldiaminophenyldisulfide, a colloidal suspension of aurous sulfide and heat ramped to 55°C during which time potassium hexachloroiridate doped Lippmann bromide, a liquid crystalline suspension of green sensitizing dye GSD-1, and 1-(3-acetamidophenyl)-5-mercaptotetrazole were added.

A high chloride silver halide emulsion is precipitated by adding approximately equimolar silver nitrate and sodium chloride solutions into a well stirred reactor containing gelatin peptizer and thioether ripener. During the silver halide grain formation, potassium hexacyanoruthenate(II) and potassium (5-methylthiazole)-pentachloroiridate are added. The resultant emulsion contains cubic shaped grains of 0.4 µm in edge length size. The emulsion is optimally sensitized by the addition of glutaryldiaminophenyldisulfide, sodium thiosulfate, tripotassium bis{2-[3-(2-sulfobenzamido)phenyl]-mercaptotetrazole} gold(I) and heat ramped to 64°C during which time 1-(3-acetamidophenyl)-5-mercaptotetrazole, potassium hexachloroiridate, and potassium bromide are added. The emulsion is then cooled to 40°C, pH adjusted to 6.0 and red sensitizing dye RSD-1 is added.

The following light sensitive silver halide imaging layers were utilized to prepare photographic label utilizing the invention label support material. The following imaging layers were coated utilizing curtain coating: Layer Item Laydown (g/m ² ) Layer 1 Blue Sensitive Layer Gelatin 1.3127 Blue sensitive silver (Blue EM-1) 0.2399 Y-4 0.4143 ST-23 0.4842 Tributyl Citrate 0.2179 ST-24 0.1211 ST-16 0.0095 Sodium Phenylmercaptotetrazole 0.0001 Piperidino hexose reductone 0.0024 5-chloro-2-methyl-4-isothiazolin-3-one/2-methyl-4-isothiazolin-3-one(3/1) 0.0002 SF-1 0.0366 Potassium chloride 0.0204 Dye-1 0.0148 Layer 2 Interlayer Gelatin 0.7532 ST-4 0.1076 S-3 0.1969 5-chloro-2-methyl-4-isothiazolin-3-one/2-methyl-4-isothiazolin-3-one(3/1) 0.0001 Catechol disulfonate 0.0323 SF-1 0.0081 Layer 3 Green Sensitive Layer Gelatin 1.1944 1) 0.1011 M-4 0.2077 Oleyl Alcohol 0.2174 S-3 0.1119 ST-21 0.0398 ST-22 0.2841 Dye-2 0.0073 5-chloro-2-methyl-4-isothiazolin-3-one/2-methyl-4-isothiazolin-3-one(3/1) 0.0001 SF-1 0.0236 Potassium chloride 0.0204 Sodium Phenylmercaptotetrazole 0.0007 Layer 4 M/C Interlayer Gelatin 0.7532 ST-4 0.1076 S-3 0.1969 Acrylamide/t-Butylacrylamide sulfonate copolymer 0.0541 Bis-vinylsulfonylmethane 0.1390 3,5-Dinitrobenzoic acid 0.0001 Citric acid 0.0007 Catechol disulfonate 0.0323 5-chloro-2-methyl-4-isothiazolin-3-one/2-methyl-4-isothiazolin-3-one(3/1) 0.0001 Layer 5 Red Sensitive Layer Gelatin 1.3558 Red Sensitive silver (Red EM-1) 0.1883 IC-35 0.2324 IC-36 0.0258 UV-2 0.3551 Dibutyl sebacate 0.4358 S-6 0.1453 Dye-3 0.0229 Potassium p-toluenethiosulfonate 0.0026 5-chloro-2-methyl-4-isothiazolin-3-one/2-methyl-4-isothiazolin-3-one(3/1) 0.0001 Sodium Phenylmercaptotetrazole 0.0005 SF-1 0.0524 Layer 6 UV Overcoat Gelatin 0.8231 UV-1 0.0355 UV-2 0.2034 ST-4 0.0655 SF-1 0.0125