Abstract: A method for chemically fogging a silver halide photographic emulsion comprising reacting cyanoborohydride anion with the silver halide thereby forming metallic silver. The cyanoborohydride is preferably in the form of an alkali metal salt. Additionally, the emulsion may optionally include a gold salt.

Abstract: A photographic light-sensitive material comprising a support having thereon at least one silver halide photographic emulsion layer with at least one of the layers of the photographic light-sensitive material containing a compound represented by the following general formula (I) or (II) ##EQU1## wherein R.sub.1, R.sub.2, and R.sub.3 each represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic ring residue, and R.sub.2 and R.sub.3 can combine to form an alkylene group; R.sub.4 represents those groups other than a hydrogen atom as described for R.sub.1, R.sub.2 and R.sub.3 ; and R.sub.5 represents an alkylene group of a polyoxyalkylene group having at least 4 carbon atoms, or the organic acid salt or mineral acid salt thereof.

Abstract: A direct positive silver halide photographic emulsion containing1. at least one dimethine dye having the general formula (I): ##EQU1## 2. AT LEAST ONE COMPOUND HAVING THE GENERAL FORMULA (II): ##SPC1##3. at least one compound having the general formula (III) ##EQU2## or the general formula (IV) ##SPC2##wherein Y, Y.sub.o, Z, L.sub.1, L.sub.2, R.sub.o, m, n, X, Z.sub.1, R.sub.1, X.sub.1, a, p, q, Y.sub.1, Y.sub.2, m.sub.1, R.sub.3, r, X.sub.2 and X.sub.3 are as hereinafter defined.

Abstract: Photographic direct-positive materials are described which comprise in admixture in a single layer or in superposed layers a monodispersed direct-positive emulsion and a heterodispersed direct-positive emulsion. By the use of both types of emulsions it is possible to obtain reduced contrast and good detail rendering in the high-light areas.

Abstract: A direct-positive photographic element is described which comprises a support and a spectrally-sensitized light-sensitive silver halide emulsion layer containing fogged silver halide grains wherein the said emulsion is spectrally sensitized by means of a dye containing a pyrrolo[ 2,1-b]thiazole nucleus which may be substituted and carry one or more fused-on rings, the said nucleus being linked by the 5- or 7-carbon atom thereof, directly or through a dimethine chain to another nitrogen containing heterocycle.

Abstract: Equidensity images can be produced by imagewise exposure and photographic processing of a photographic material containing at least two silver salt emulsions which may be arranged in one layer as a mixture or in two layers, wherein one silver salt emulsion is a fogged direct positive emulsion and the other is a negative emulsion.

Abstract: Silver halide emulsion layers are formed by applying a water-soluble silver halide complex to a gelled substrate, and treating to decomplex to form silver halide crystals therein.

Abstract: My invention is directed to a photographic element capable of forming either a positive or a negative image, depending upon the choice of electromagnetic wavelengths to which it is exposed. The element inludes internally fogged photographic silver halide grains which are substantially free of surface fog. Associated with the grains is a desensitizer containing an imidazoquinoxaline nucleus having a reduction potential more positive than -0.90 volts and an oxidation potential more positive than +0.80 volt. The desensitizer is present in an amount of no more than that required to cover 25 percent of the silver halide grain surfaces. Also associated with the grains is a spectral sensitizing dye having an absorption peak at least 20 nm removed from any absorption peak exhibited by the desensitizer.

Abstract: A direct-positive photographic material for producing images by fogging development wherein the photographic material contains an unfogged silver halide emulsion layer. The silver halide grains in the unfogged emulsion have a layered grain structure wherein there is a first phase in which is localized a relatively high silver chloride content of at least 20 mol percent based on the total silver halide content of the grain. A second phase contains from less silver chloride than the first phase down to no silver chloride and the total silver chloride in the grain does not exceed 30 mol percent.The physical position of the first phase in the grain is not critical.The emulsion is either not chemically sensitized or only slightly sensitized.The photographic material and its use includes both producing black and white and colored photographic images and has high sensitivity to light and by fogging development yields pure image whites.

Abstract: Direct positive silver halide materials based on the Herschel effect having substantially reduced sensitivity to room light exposure contain a heterocyclic compound to prevent white light bleaching along with a second heterocyclic compound to prevent latent image formation due to white light exposure.

Abstract: A silver halide photographic emulsion for direct positives, containing a fluorene compound having at least one nitro group as a substituent.

Abstract: Photographic silver halide emulsions are prepared which have their sensitivity increased by the addition of at least one macrocyclic polyamine, a salt, or a metal chelate thereof, said macrocyclic polyamine having the formula--(NH -- (CH.sub.2).sub.n).sub.m --Where m is 4-7 and each n is independently 2-5.