Brown to Dark Brown Dye

摘要

One of the objects of the present invention is to provide a coloring agent for brown to brown pigments having excellent acid resistance and / or salt resistance and capable of inhibiting the occurrence of precipitation, spots and staining even when used under conditions of low pH or high salt concentration . When brownish or brownish coloring matter is dissolved in water so as to have a color value E of ^{10%(500 nm)} = 0.1, citric acid is added in an amount of 1% by weight to give a brownish to brownish coloring matter Of the present invention have characteristics of excellent acid resistance and / or salt resistance, and even when used under conditions of low pH or high salt concentration, the coloring matter, The occurrence of coloring unevenness and the like can be suppressed.