Abstract: Photographic elements particularly adapted for forming direct-positive images are disclosed in which a radiation-sensitive core-shell emulsion layer and a silver halide emulsion layer incapable of forming a surface latent image within the direct-positive exposure latitude of the first emulsion layer and containing a grain population capable of internally trapping photolytically generated electrons are both present. The photographic elements are capable of exhibiting increased covering power, greater maximum density, and increased speed.

Abstract: A post-activation type dry image forming material comprising (I) a silver salt component reducible to free silver upon light exposure and including silver iodide; (II) a redox reactive composition capable of making a visual change by a redox reaction of said composition, said reaction being initiated by heating in the presence of free silver; (III) an oxidizing agent for free silver which has an oxidizing capacity for free silver but is rendered photosensitive by heating and which, upon light exposure after said heating, is suppressed with respect to the oxidizing capacity for free silver and capable of catalytically promoting the redox reaction of said composition; and (IV) a photoreactive oxidizing agent, upon light exposure, capable of returning the reduced oxidizing agent for free silver to the original state.

Abstract: Photographic elements particularly adapted for forming direct-positive images are disclosed in which a radiation-sensitive core-shell emulsion layer and a silver halide emulsion layer incapable of forming a surface latent image within the direct-positive exposure latitude of the first emulsion layer and containing a grain population capable of internally trapping photolytically generated electrons are both present. The photographic elements are capable of exhibiting increased covering power, greater maximum density, and increased speed.

Abstract: Silver halide emulsions lack stability in that their properties vary over a period of time. Various stabilizers have been used to reduce the rate and degree of variation. The combination of uracils and nitroso-substituted phenols has been found to provide a synergistic stabilization of speed in silver halide emulsions. Other stabilizers may be combined with those two classes to further improve the stability of the emulsion.

Abstract: Silver halide emulsion with an average grain size of at most 0.6 .mu.m containing Co-, Ce- or Cu-salts are suitable for the production of vesicular images.

Abstract: A radiation-sensitive emulsion for use in forming a direct-positive image is disclosed. The emulsion is comprised of core-shell silver halide grains. The shell portions of the grains contain polyvalent metal ions to reduce rereversal.

Abstract: A silver halides photographic material with improved keeping quality, said material having a substrate formed by coating a base web with a film-forming resin, preferably a polyolefin resin, said base web being composed principally of natural pulp or a mixture of two or more different types of natural pulp having a post color number of 2 or below, said post color number being defined by the following formula: ##EQU1## [wherein Ro is brightness (%).times.(1)/(100) before fading treatment, R is brightness (%).times.(1)/(100) after 18-hour fading treatment at 85.degree. C. and 95% RH, and P is post color (PC) number which indicates the degree (nondimensional number) of fading].

Abstract: A silver halide photographic light-sensitive material is described comprising a support having thereon at least one light-sensitive silver halide emulsion layer, said silver halide emulsion layer containing a rhodium salt in an amount sufficient to increase a contrast thereof, and said silver halide emulsion layer or a layer adjacent thereto containing a compound represented by the following formula (I) or (II), and a process for producing a silver halide photographic emulsion containing rhodium salts is also described which comprises adding a rhodium salt into a silver halide photographic emulsion in an amount sufficient to increase a contrast before the conclusion of first ripening and adding a compound represented by the following formula (I) or (II) into the resulting emulsion after washing to remove useless salts ##STR1## wherein R.sub.1 represents hydrogen or a substituted or unsubstituted alkyl group.

Abstract: A novel method of forming high contrast silver images is provided. The method comprises steps of (1) imagewisely exposing a light-sensitive silver halide photographic material, and (2) treating the exposed material with a developer having superadditivity. The method is characterized by the co-existence of an oxidizing agent, and a water-insoluble ion pair formed by a water-soluble cationic compound such as quaternary ammonium or tertiary sulfonium salt and a water-soluble anionic compound such as organic sulfate. The method realizes high contrast photographic images by using a developer having a good preservability, without contamination of the developer, within a short period of time for the development. There is also provided a light-sensitive silver halide photographic material herein.

Abstract: This invention relates to photographic materials containing an ion pair compound which has a quaternary nitrogen atom as a cation and a boron compound as an anion.

Abstract: A process for preparing silver halide emulsions having high sensitivity and contrast by adding water-soluble iridium compounds during precipitation or physical ripening and adding water-soluble iodide compounds and sulfer sensitizers during chemical ripening.

Abstract: A thermally developable light sensitive material which comprises: (a) an organic silver salt; (b) a photocatalyst and (c) a reducing agent in a support or in one or more layers provided on the support additionally comprises (d) at least one cerium compound selected from trivalent and/or tetravalent cerium compounds in the support and/or in one or more of the above layers. An improvement in various characteristics such as a long green shelf life, a high degree of whiteness, low thermal fog, high sensitivity and so on is obtained.

Abstract: A dry image forming material comprising (a) a non-photosensitive organic silver salt oxidizing agent, (b) a reducing agent for a silver ion and (c) a halogen molecule, which material is excellent in that a high sensitivity can be obtained and the occurrence of fog is extremely small. The sensitivity can be further improved by incorporation of a halogen ion source in addition to the halogen molecule. Furthermore, the dry image forming material can be improved, with respect to light stability of the raw image forming material and stabilities to heat and humidity, by incorporation of a nickel compound and/or a cobalt compound. In the dry image forming material of this invention, further incorporation of a carboxylic acid anhydride exerts a remarkable anti-fogging effect. The dry image forming material of this invention is non-photosensitive under normal lighting conditions and therefore, can be prepared, handled and stored in a light room.