Direct reversal emulsions and photographic elements useful in image transfer film units

A radiation-sensitive emulsion capable of forming a direct-positive reversal dye image comprised of gelatin or a gelatin-derived peptizer, surface chemically sensitized silver bromide or bromoiodide grains capable of forming an internal latent image, a dye image former, and a nucleating agent,

• at least 70 percent of the total projected area of said grains being provided by tabular grains which have an average diameter of at least 1.0 micron, an average thickness of less than 0.3 micron, and an average aspect ratio of at least 10:1, and
• said emulsion when coated on a transparent film support at a silver coverage of 4 grams per square meter, exposed to a 500 watt tungsten lamp for times ranging from 0.01 to 1 second at a distance of 0.6 meter, developed for 5 minutes at 20.degree. C. in Developer Y below, fixed, washed, and dried, having a maximum silver density at least five times the maximum density of an identical test portion which has been exposed in the same way and developed for 6 minutes at 20.degree. C. in Developer X below, fixed, washed, and dried:
• ______________________________________ Developer X Grams ______________________________________ N--methyl-p-aminophenol sulfate 2.5 Ascorbic acid 10.0 Potassium metaborate 35.0 Potassium bromide 1.0 Water to 1 liter. ______________________________________
• ______________________________________ Developer Y Grams ______________________________________ N--methyl-p-aminophenol sulfate 2.0 Sodium sulfite, desiccated 90.0 Hydroquinone 8.0 Sodium carbonate, monohydrate 52.5 Potassium bromide 5.0 Potassium iodide 0.5 Water to 1 liter. ______________________________________

In a multicolor direct reversal photographic element comprised of

• a film support and, located thereon,
• color-forming layer units for separately recording blue, green, and red light containing yellow, magenta, and cyan dye-forming couplers, respectively,
• said color-forming layer units being chosen so that when said photographic element is exposed at a color temperature of 5500.degree. K. through a spectrally nonselective step wedge and processed said photographic element exhibits, in relation to blue contrast and speed, green and red contrast variations of less than 20 percent and green and red speed variations of less than 0.3 log E,
• each of said color-forming layer units including at least one emulsion layer comprised of a dispersing medium, silver halide grains, and a nucleating agent,
• said silver halide grains of at least a triad of said emulsion layers for separately recording blue, green, and red light being positioned to receive exposing radiation prior to any remaining emulsion layers and having an average diameter of at least 2.0 microns,
• the improvement wherein at least 70 percent of the total projected area of internal latent image-forming tabular silver bromide or bromoiodide grains in at least one of said green and red recording emulsion layers have an average thickness of less than 0.2 micron, an average diameter of at lest 0.6 micron, and an average aspect ratio of at least 10:1, said internal latent image-forming tabular grains in said green and red recording emulsion layers being both internally and surface chemically sensitized.

In a photographic image transfer film unit comprising

• a support,
• at least one emulsion layer located on said support containing a dispersing medium, radiation-sensitive internal latent image-forming silver halide grains, and a nucleating agent,
• a dye-image-providing material present in said emulsion layer or a layer adjacent thereto, and
• a receiving layer for providing a viewable transferred dye image following imagewise exposure and processing of said emulsion layer,
• the improvement, wherein internal latent image-forming tabular silver halide grains in at least said one emulsion layer having an average thickness of less than 0.5 micron, an average diameter of at least 0.6 micron, and an average aspect ratio of greater than 8:1 account for at least 50 percent of the total projected area of said radiation-sensitive silver halide grains present in said emulsion layer.

In a dye image transfer film unit comprising

• a transparent support,
• at least one emulsion layer located on said support containing a dispersing medium, radiation-sensitive internal latent image-forming silver halide grains, and a nucleating agent,
• a dye-image-providing material located in said emulsion layer or in a layer adjacent thereto,
• a transparent cover sheet,
• a dye receiving layer located on said cover sheet,
• an alkaline processing solution, and
• means for releasing said alkaline processing solution into contact with said emulsion layers,
• the improvement wherein at least 70 percent of the total projected area of said radiation-sensitive silver halide grains is provided by internal latent image-forming tabular silver halide grains having an average thickness of less than 0.5 micron, an average diameter of at least 0.6 micron, and an average aspect ratio of at least 10:1 .

In a multicolor dye image transfer film unit comprising

• a support,
• dye-providing layer units located on said support each comprised of at least one dye-image-providing material and at least one silver halide emulsion containing a dispersing medium, radiation-sensitive internal latent image-forming silver halide grains, and a nucleating agent, said dye-providing layer units including a dye-providing layer unit containing a red-sensitive emulsion and a cyan-dye-image-providing material, a dye-providing layer unit containing a green-sensitive emulsion and a magenta-dye-image-providing material, and a dye-providing layer unit containing a blue-sensitive emulsion and a yellow-dye-image-providing material, and
• a receiving layer for providing a viewable transferred multicolor dye image following imagewise exposure and processing,
• the improvement wherein at least 70 percent of the total projected area of said radiation-sensitive grains in at least one of said emulsions is provided by internal latent image-forming tabular silver halide grains having an average thickness of less than 0.5 micron, an average diameter of at least 1.0 micron, and an average aspect ratio of at least 10:1.