Abstract: The tamper-proof document consists of a photographic material as information carrier comprising front- and back gelatine layers, the outer of the gelatine layers of which contain particles of a homo- or copolymer of an acrylic and/or methacrylic acid ester. The information carrier is laminated on one or both sides to a transparent foil by means of a hardenable adhesive. The document is remarkably safe against falsification.

Abstract: New silver halide emulsions are prepared at least partly by converting a silver phosphate with a water soluble halide.

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: Silver halide emulsions, which have been precipitated in the presence of polymers having recurring units with a 8-hydroxy quinoline structure are suitable for the preparation of vesicular images.

Abstract: Silver halide emulsions are prepared by precipitating a silver halide emulsion I on a more sparingly soluble silver halide emulsion II in the presence of a silver halide solvent wherein the emulsion I has been prepared in the presence of a compound inhibiting grain growth.

Abstract: A photographic material with at least one light-sensitive silver halide emulsion is disclosed. The emulsion has been prepared by carrying out the precipitation of the silver halide in the presence of certain imidazoles.

Abstract: An improvement in the stability of a direct positive emulsion layer in photographic material is obtained by the inclusion of a compound which provides in the image-wise exposed and developed direct positive emulsion layer a greater difference between the density of the image in the unexposed parts of the layer and the density in the exposed parts. The compound provides in the emulsion a characteristic curve related to a density value at maximum density which is at least twice the analogous density value at minimum density.

Abstract: Silver halide is precipitated in a large excess of a soluble chloride that forms together with silver ions a silver salt more readily soluble than the silver salt of the final emulsion. By precipitation of silver halide in the presence of the soluble chloride used in excess part of the silver chloride is carried along with the less soluble silver halide and may subsequently be converted into the less soluble silver halide.

Abstract: A silver halide emulsion is made by continuous conversion of a more soluble silver halide into a less soluble silver halide. From a first part of up to 50% of the total amount of silver nitrate by reaction with a first water soluble halide a silver halide is precipitated consisting at least partly of a more readily soluble silver halide, e.g. silver chloride. In the presence of this more readily soluble silver halide the remaining silver nitrate is reacted with a second water soluble halide composition to form the residual silver halide (main precipitation). The amount of total halide in the precipitation is slightly more than equivalent to the amount of silver ions. However the amount of halide that forms the less readily soluble silver halide is less by at least 5 mol% than equivalent to the amount of silver ions in the precipitation medium.

Abstract: Relief or resist images can be produced by means of a photosensitive material including a photosensitive layer with a polymer as defined hereinafter containing vinyl groups capable of being cross-linked upon exposure to actinic light to yield unsoluble cross-linked products at the exposed areas while the polymer in the unexposed areas remain soluble.

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: Photosensitive polymers and their process of preparation which can be crosslinked by a vinyl polymerization initiated by photochemical means and which are derived from the reaction of polymers containing zerewitinoff-active hydrogen atoms with N-methylol compounds or with N-Methylol ethers of acrylamides or substituted acrylamides. The modified polymers optionally in admixture with other vinyl group containing monomers are useful for purposes such as photosensitive copying layers, coatings and molded articles.