Agfa Gevaert Nv

Fernand I Ketels

Jean-Marie O Dewanckele

Piet Kok

Benedictus J Jansen

Werner J Van De Wynckel

Jozef P De Prijcker

Paul Smet

Michiels Frank

An apparatus for desilvering silver-containing solutions comprises an electrolytic cell (10) having an anode (20), a cathode (30) and a reference electrode (45) positioned adjacent the cathode (30), and electrical power supply control means (41) for controlling the supply of electrical power to the anode (20) and the cathode (30). The power supply control means (41) includes means (60) for adjusting the cathode potential and control means (70) linked to said adjustment means (60) to reduce the cathode potential, at least periodically, as the desilvering process continues. The process leads to better silver adhesion on the cathode occurs, while maintaining good desilvering levels in the solution, and cathode poisoning is minimised.

Process and apparatus for desilvering a silver-containing solution

Method for the production of direct-positive images by image-wise exposing a light-sensitive silver halide material comprising a support and an internal latent image-type silver halide emulsion layer and developing said exposed material in the presence of at least one development nucleator and density-increasing amounts of a compound chosen from the class consisting of formic acid, oxalic acid, glyoxylic acid, or salts of these and/or of a compound chosen from the class consisting of polyethylene glycols, with a hydroquinone-type developing solution having a pH not higher than 12.0 and comprising less than 25 g per liter of a hydroquinone and 5 to 100 g per liter of at least one alkanolamine.

Method of developing direct positive silver halide material

Growing community of inventors

Kontich, Belgium

Fernand I Ketels