4.1 Test Method A determines the amount of color produced when the pigment is in direct contact with a selected solvent such as toluene. It is useful as a rapid, easily conducted test of the general bleeding characteristics of pigments.
4.2 Test Method B determines the amount of color migration into a white film applied over a base coat containing the pigment. It may give a more practical evaluation of whether a pigment will meet specific requirements for bleed resistance.
1.1 These test methods cover procedures for determining the bleeding characteristics of dry pigments by direct solvent extraction of the pigment and by overstriping a film with a white coating and observing for the color migration from the base coat containing the pigment.