GB767701A - Improvements in photographic developer compositions - Google Patents

Abstract

767,701. Photographic developers. KODAK, Ltd., Aug. 3, 1954 [Aug. 3, 1953], No. 22507/54. Class 98(2) A photographic developer composition, in wet or dry form, comprises an alkaline material, a 3-pyrazolidone silver halide developing agent, and dihydropyrogallol or an ene-diol compound of the general formula wherein R is an alkyl or alkoxy group or a halogen atom and Z is S, O, or a methylene, imino, or N-alkylimino group. The 3-pyrazolidone developing agent-may have the general formula wherein R 1 to R, can be hydrogen or alkyl or aryl groups. Numerous 3-pyrazolidones are specified, including 1-phenyl-3-pyrazolidone, 5-methyl-3-pyrazolidone, 1-acetamidophenyl-3-pyrazolidone, 1-p-hydroxyphenyl-4 : 4-dimethyl-3-pyrazolidone, 1-(7- hydroxy-2-naphthyl)-4- methyl-4-n-propyl - 3-pyrazolidone, 1-o-chlorophenyl-4-methyl- 4-ethyl-3-pyrazolidone,. 1-p-diphenyl-4 : 4- dimethyl-3-pyrazolidone, 1-(p-#-hydroxyethylphenyl)-3-pyrazolidone and 1-phenyl- 2-acetyl-4 : 4-dimethyl-3-pyrazolidone. The ene-diol compound may be coumarindiol, thiacoumarindiol, carbostyrildiol, 1 : 2-3- trihydroxynaphthalene, 6-methyl-thi.acdumarindiol, or N-methylcarbostyrildiol. The activity and stability of the developer are both increased as compared with developers not containing both erie-diol and 3- pyrazolidone compounds, and when the developer is free from silver halide solvents such as sodium sulphite, it behaves as a strong surface latent image developer. In examples, the developer compositions are .(1) 1-phenyl-3-pyrazolidone, dihydropyrogallol, sodium sulphite, sodium sesquicarbonate, and sodium hydroxide, and (2) sodium hexametaphosphate, sodium sulphite, sodium carbonate, potassium bromide, potassium iodide, 1 - phenyl - 3 - pyrazolidone - dihydropyrogallol, and 1 - phenvl - 5- mercaptotetrazole. Specifications 542,502, 561,875, 757,271 and 767,705 [Group IV(b)] are referred to.