Agfa-gevaert Ag

Agfa-gavaert, A.g.

Helmut Haseler

Heinz Meckl

Gustav Tappe

Werner Berthold

Adolf Seiler

Peter Bergthaller

Erich Wolff

Ubbo Wernicke

Immo Boie

Sieghart Klotzer

Paul Marx

Fritz Nittel

Helmut Kampfer

Ernst Meier

Wolfgang Lassig

Karl Kuffner

Karl Lohmer

Willibald Pelz

Gertrud Kirchhoff

Herbert Stark

Gunter Von Der Kall

Hans Hischlager

The present invention relates to a photographic reversal process for the production of positive photographic images by imagewise exposure of the photosensitive material containing at least one silver halide emulsion layer, black-and-white first development of the material, chemical fogging or diffuse second exposure and subsequent color development, characterized in that

Photographic reversal process

A new process for maintaining the properties of the developer in the preparation of colored images by development of exposed silver halide-containing material at an alkaline pH in a developer bath containing p-phenylenediamine derivative and at least 40 mol-% of the silver halide consisting of silver chloride and replenishing the color developer in the bath in such a limited quantity that no overflow occurs but it is sufficient to make up for the loss of bath constituents. This process preserves the sensitive results from development during use of the developer bath.

Process for the production of color photographic images comprising

Excellent image silver stability is obtained without intermediate washing after fixing and without a special finishing bath by a process for stabilizing a silver image produced by exposure, development and fixing of a photographic material containing at least one silver halide emulsion layer, in which, immediately after fixing, the photographic material is subjected to treatment by a stabilizing bath containing a compound corresponding to general formula (I) ##STR1## in which X=Cl, Br

Process for stabilizing photographic silver images

In the case of color materials with the usual processing times, bleaching and bleaching/fixing baths containing an iron(III) ion complex salt as bleach and, in addition, a 5- to 7-membered heterocyclic compound containing at least one N-atom and at least one other hetero atom from the group consisting of O,S,N which is substituted by --S.sup..crclbar. and, at a quaternary ring nitrogen atom, carries a positive charge arranged in such a way that no tautomeric charge compensation to a neutral thione form is possible, provide for good bleaching, i.e. for black areas free from residual silver in the case of color negative materials and for low minimum densities in the case of color reversal materials, by virtue of their excellent bleaching rate and, at the same time, their high stability.

Bleaching baths containing bleaching accelerators

In a process for the processing of color photographic silver halide material which has been exposed to form an image by development, bleachfixing, washing or stabilization and drying, the aqueous developer solution being free from benzyl alcohol, the pH value of the bleachfixing solution, which contains an iron(III) complex salt, being below 7 and the bleachfixing solution containing a compound corresponding to general formula (I) ##STR1## in which Z represents the atoms required to complete an optionally further substituted heterocyclic ring and

Process for processing a color photographic material

Photographic recording materials which contain a developer substance or a precursor thereof produce better results if in addition they contain a sulphite, a disulphite or a compound capable of releasing sulphite in the photographic material.

Photographic recording material and process for the production of

Developer compositions which contain a hydrolyzed polymaleic acid anhydride having improved protection against precipitation of calcium compounds.

Photographic developer composition

A new process for the purification of photographic developer compounds using an anionic surfactant wherein unwanted impurities are removed either by being precipitated or dissolved. In this process the developer substance is freed from difficult to remove impurities.

Process for the purification of photographic developer substances

Color images are obtained by chromogenic development of a colorphotographic material comprising several differently spectrally sensitized silver halide emulsions and color couplers associated thereto, a hydrophobic cyan coupler being incorporated by means of a hydrophobic coupler solvent and a hydrophobic yellow coupler being incorporated without a coupler solvent, when a color developing composition is used comprising a hydrophilic and a hydrophobic color developer compound. The color images have good stability of the cyan partial image to tropical conditions and good lightfastness of the yellow partial image.

Color-photographic development process

Compounds of the formula ##STR1## are useful in photographic materials and processes for the color development.

Color photographic material and color photographic processes

White couplers which are capable of reacting with color developer oxidation products to form colorless end product with the consumption of four oxidation equivalents and which, therefore have increased absorption capacity for color developer oxidation products correspond to the formula ##STR1## or its tautomeric form, in which R.sup.1 is hydrocarbyl, heterocyclyl attached through a ring carbon, or --CO--R.sup.2 R.sup.2 is alkyl, aryl, alkoxy, amino X is --S-- or --NR.sup.3 -- R.sup.3 is hydrogen, same as represented by R.sup.1 or an electron-attaching group. The four-equivalent white couplers may be contained in processing solutions or, in diffusion resistant form, in one or more layers of a colorphotographic material.

Process for the production of color photographic images using new white

The dosing device is installed between a funnel-shaped storage container for the pulverulent material and an open vessel underneath it. It consists of a flat plate arranged between the open vessel and the outlet aperture of the storage container so that a standing column of material is formed between this plate and the outlet aperture, and a dosing rod which is displaceable or rotatable in a horizontal plane. The dosing rod is passed periodically through the column of substance and with each passage conveys an approximately constant quantity of material into the vessel underneath it. This device is also capable of dosing materials which tend to stick together and cake to the apparatus.

Dosing device for pulverulent material

Photographic bleach-fix baths containing iron-III-complexes of aminopolyacetic acids as oxidizing agents are rejuvenated by reducing the iron-III-complexes with a reducing agent other the iron and thereafter are desilvered by treatment with iron.

Process for the regeneration of photographic bleach-fix baths

Photographic bleach fix baths are desilvered by electrolysis in a cell in which the cathode and anode chambers are separated by a diaphragm, with the exclusion of air, and the bleach fix bath is removed from the cell before the potential is switched off. For increasing the current yield the bleaching agent can be reduced prior to electrolysis for example by the addition of sodium dithionite.

Growing community of inventors

Leverkusen, Germany

Helmut Haseler