The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 09, 1978
Filed:
Nov. 20, 1975
Agfa-Gevaert Aktiengesellschaft, Leverkusen, DT;
Abstract
A neutralization system for the dye diffusion transfer process comprises an acid polymer layer containing a polymer with free acid groups and a retarding layer. The retarding layer contains a hydratable polymer which in its non-hydrated state is a barrier for hydroxyl ions and in its hydrated state provides no resistance for diffusing hydroxyl ions. The retarding layer is arranged between a laminate consisting of a light-sensitive film unit comprising at least a light-sensitive silver halide emulsion layer and a non-diffusible dye giving compound associated with the light-sensitive silver halide emulsion layer. The retarding layer allows a first high pH value to be maintained during a first time interval which is sufficient and necessary for producing the desired image density in the image receiving layer and thereafter a second low pH value to be adjusted within a second time interval which is less than half as long as the first. Suitable polymers for the retarding layer are homo-, co- and graftpolymers of 1,2-dimethoxyethylene.