Abstract: Stabilizing baths used in rapid reproduction processes of photographic elements which comprise stabilizers, hardening additives and corrosion preventatives are improved in that certain heterocyclic compounds are incorporated in the baths. Excellent protection against corrosion is attained without a deleterious effect on the quality of the photographic material.
Type:
Grant
Filed:
May 1, 1978
Date of Patent:
June 24, 1980
Assignee:
AGFA-Gevaert, A.G.
Inventors:
Werner Berthold, Artur Botta, Anita von Konig, Christian Rasp
Abstract: An aqueous acidic etch-bleach solution comprising hydrogen peroxide, iron(III)ions and inorganic anions that form a silver salt having a solubility product not greater than 1.times.10.sup.-8 determined in water at 20.degree. C., characterized in that such solution contains in the dissolved state the combination of citric acid and a polymer containing alkylene oxide units for improved stabilization of the hydrogen peroxide.
Type:
Grant
Filed:
June 1, 1978
Date of Patent:
May 20, 1980
Assignee:
AGFA-GEVAERT N.V.
Inventors:
Danie A. Claeys, Albert A. Reyniers, Wilhelmus Janssens
Abstract: Quinoxalines of the formula ##STR1## are provided, in which R.sub.1 and R.sub.2 independently are lower alkyl R.sub.3 is lower alkyl, --CH.sub.2 OR.sub.5, --CH.sub.2 NRR', --CH.sub.2 OCOR, --CH.sub.2 Cl, --CH.sub.2 Br, --CH.sub.2 SR, --CH.sub.2 O(CH.sub.2).sub.p OR, --CH.sub.2 PO(OR.sub.5).sub.2, --CH.sub.2 PO(OR.sub.6).sub.2, --CH.sub.2 SO.sub.3 R.sub.6, --O(CH.sub.2).sub.m OR, --O(CH.sub.2).sub.p SO.sub.3 R.sub.6 or --(OCH.sub.2 CH.sub.2).sub.n OAr, R.sub.4 is hydrogen, lower alkyl or alkoxy when R.sub.3 is other than lower alkyl, or R.sub.4 is --OH, --NRR', --NHCOR, --NHCOAr', --NHSO.sub.2 R.sub.5 or --NHSO.sub.2 Ar', R and R' independently are hydrogen or lower alkyl, R.sub.5 is lower alkyl, R.sub.6 is hydrogen, an alkali metal cation or --N.sup..sym. (R).sub.4, Ar is aryl or sulphonated aryl, Ar' is aryl or substituted aryl, m is 3 or 4, n is 1 to 3 and p is 2 to 4.The quinoxalines are useful as bleach catalysts, especially as dye bleach catalysts, for the photographic silver dye bleach process.
Abstract: The processing of exposed photographic silver halide color materials is described while using a bleach or bleach-fixing bath containing better bleach-accelerating compounds. The bleach-accelerating compounds are polyoxyethylene compounds comprising at least 20 mol % of recurring oxyethylene units, which carry a thioether group in a sidechain.
Type:
Grant
Filed:
October 17, 1978
Date of Patent:
May 6, 1980
Assignee:
Agfa-Gevaert, N.V.
Inventors:
Robert J. Pollet, Camille A. Vandeputte, Francis J. Sels, George F. van Veelen
Abstract: A two-step black and white photographic process in which conventional black and white developing of latent images in a silver halide black and white emulsion first is carried out and then, instead of simply fixing the developed emulsions containing black and white images, the emulsions are fixed and bleached concurrently for a short period of time long enough to perform the fixing and to enable a controlled mild degree of bleaching to occur. Such bleaching is carried out only for a time long enough selectively to attack low-density areas of freshly developed black and white images at a greater rate than areas of heavier density so as to depress the toe of the D log E curve without markedly affecting the balance of the curve, thus enhancing the images by obtaining a general increase of contrast, a reduction or total elimination of fog and a reduction or elimination of film haze, this latter being applicable primarily to radiology.