9 ноября, 2015 
Pokraskin Tolerance to an individual solvent is tested by enclosing a certain amount of pigment powder in a piece of filter paper, which is then immersed in the organic solvent for a given amount of time. The extent of coloration of the test solvent indicates the solvent fastness of the pigment.
In another method for evaluating overcoating fastness, a uniform coating containing test pigment (generally a full shade) is overcoated with a uniform film of white paint to yield complete hiding. After complete drying, pigment migration from the base coat into the white topcoat and hence discoloration of the latter is determined visually or colorimetrically. The binder system for base coat and white top coat are generally selected based on the actual coating system in which the pigment is to be used. Further information on bleeding tests is in ISO 787-16 and ASTM D279.
The water-soluble matter can be determined by extraction of a known amount of pigment sample with water followed by filtration and evaporation of the filtrate to dryness in order to gravimetrically determine water-soluble.
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