| 摘要 |
PURPOSE:To speed up silver bleaching by incorporating diethylenetriaminepentaacetic acid ferric complex salt and regulating pH to a specified value. CONSTITUTION:Diethylenetriaminepentaacetic acid ferric complex salt is contained and pH is regulated to >=5.0. In a bleach fixing soln. using an ordinary aminopolycarboxylic acid ferric complex salt, oxidation reduction potential rises with rise of pH, but in the bleach fixing soln. using this diethylenetriaminepentaacetic acid ferric complex salt, the rise of reduction potential is very small. On the other hand, the bleaching speed of image silver almost coincides with the result of oxidation reduction potential, and in a bleach fixing soln. composed of usual aminocarboxylic acid ferric complex salt, the bleach fixing force drops abruptly at >=6.8, especially, >=7.5 in pH, but on the contrary, in the bleach fixing soln. made of diethylenetriaminepentaacetic acid ferric complex salt, desilvering speed does not drop at all even if pH is raised, and higher bleaching force can be retained. |
