GB668483A - Apparatus for developing photographic materials by means of a gas - Google Patents

Abstract

668,483. Photographic gas developing apparatus. CELLOPHANE SOC. ANON. Jan. 3, 1950 [Feb. 1, 1949], No. 156/50. Class 98 (ii). The apparatus comprises a chamber to which is supplied or in which is generated a developing gas, and which has two perforated side walls converging towards the bottom in smooth curves, an endless conveyer belt for the light sensitive material to be developed which passes over the two perforated faces, and a guide roller for said belt rotatably mounted in a recess formed in the bottom wall of the chamber between the two perforated walls. As shown, the material to be developed typically diazotype paper prints prepared in a contact printer having a transparent cylinder 18 with a central light source 20, is fed to the developing machine at 6 through which it is moved by an endless belt driven by rollers A, B, the roller B being the more slowly driven, the belt passing over a roller 25 in a recess 23 in the chamber between the adjacent boundaries of the curved perforated faces. To ensure smooth passage of the paper across the gap between these faces and the roller, fingers 24 are formed on the chamber walls adjacent the recess and extend into grooves in the roller. The developing gas is generated by heating an aqueous ammonia solution in a drip-fed well 8 with an electric element 9, and electric heaters 10, 11 are provided to maintain the gas at the desired temperature. The developed paper is de-odorized by passage over a heated plate 12 outside the developing chamber, and/or by the provision of a compartment 14, including a portion of the second perforated face of the developing chamber but isolated from the rest of the chamber, through which fresh air is circulated.