G - Physics – 03 – C
Patent
G - Physics
03
C
96/68
G03C 5/30 (2006.01) G03C 5/26 (2006.01) G03C 5/29 (2006.01) G03C 5/305 (2006.01)
Patent
CA 2013294
43944CAN4A Concentrated Photographic Developer Composition And Method of Making It ABSTRACT OF DISCLOSURE A concentrated alkaline photographic developer com- position, packaged in a single part to be diluted with water to form a ready to use developing solution for sil- ver halide photographic materials, which comprises di- hydroxybenzene developing agents, inorganic alkali agents, inorganic antioxidant agents, sequestering agents and antifoggants, wherein said inorganic antioxidant agents comprise Na2SO3 (sodium sulfite) and K2SO3 (potas- sium sulfite in a molecular ratio of 1:1 to 1:3 in an amount of from 1.6 to 4 moles per liter, the molecular ratio between said inorganic antioxidant agents and the developing agents is from 1.50 and 4.00, and said concen- trated developer composition has a specific gravity high- er than 1.300 at 20°C, and a method of making a concentrated alkaline photo- graphic developer composition, packaged in a single part to be diluted with water to form a ready to use develop- ing solution for silver halide photographic materials, which comprises dihydroxybenzene developing agents, inor- ganic alkali agents, inorganic antioxidant agents, se- questering agents and antifoggants, characterized in that comprises the following steps: a) preparing an aqueous KOH concentrated solution having a specific gravity not higher than 1.110 at 20°C, b) adding to the resulting solution inorganic anti- oxidant agents which form sulfite anions (SO3) in aque- ous solution, at least half in moles of which being Na2S2O5 (sodium metabisulfite), in a quantity of from 0.8 to 2 moles per liter, c) adding to the resulting solution further aqueous KOH concentrated solution until the specific gravity of the resulting solution is 2 1.175 at 20°C, d) adding to the resulting solution developing agents in such a quantity that the molecular ratio be- tween said inorganic antioxidant agents and the develop- ing agents is from 1.5 to 4.00, and e) adding the other components of the developer com- position in such a quantity to obtain a concentrated de- veloper composition having a specific gravity higher than 1.300 at 20°C.
Minnesota Mining And Manufacturing Company
Smart & Biggar
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