| 摘要 |
PROBLEM TO BE SOLVED: To obtain a homogeneous concentrated one-part type color developing composition capable of replenishment at a low rate by incorporating a specified free base type color developing agent and an antioxidant for the color developing agent. SOLUTION: The homogeneous one-part type color developing concentrate of pH 7-13 contains a) at least 0.06 mol/l free base type color developing agent, b) at least 0.05 mol/l antioxidant for the color developing agent, c) water, d) a water-miscible or water-soluble hydroxy-substituted straight chain organic solvent having a molecular weight of 50-200 and present in the concentrate at such a concentration as to give a water to solvent weight ratio of 15:85 to 50:50 and e) a buffer soluble in the organic solvent but does not contain chloride ions. The color developing agent is preferably aminophenol or p- phenylenediamine, in particular N,N-dialkyl-p-phenylenediamine. One or more antioxidants are usually contained so as to protect the color developing agent from oxidation.
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