This specification establishes quality requirements and provides a basis for common understanding among producers, distributors, and users.

It is not intended that all paints meeting the requirements be identical nor of uniform excellence in all respects. Variations in manufacture, not covered by this specification, may cause some artists to prefer one brand over another, either of which may be acceptable under this specification.

This specification establishes the requirements for composition, physical properties, performance, and labeling of gouache paints. Covered here are pigments, vehicles, and additives, wherein the requirements for which are included for pigment identification, lightfastness, and consistency. Some pigments meeting the lightfastness requirements in this specification are listed herein. Also, in order to identify other pigments that meet these requirements, instructions are given for test specimen preparation and the respective test methods for determining relative lightfastness. The conditions not covered in this specification that affect gouache paints are substrate, environmental conditions, storage, vehicles, pigments, additives, inerts, preparation of samples, coarse particles, fineness of dispersions, consistency, freeze-thaw stability, opacity (hiding power), bleeding, and color specification.

1.1 This specification establishes requirements for composition, physical properties, performance, and labeling of gouache paints.

1.2 This specification covers pigments, vehicles, and additives. Requirements are included for pigment identification, lightfastness, and consistency.

1.3 Table 1 lists some pigments meeting the lightfastness requirements in this specification. In order to identify other pigments that meet these requirements, instructions are given for test specimen preparation. Test methods for determining relative lightfastness are referenced.

1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

X2.1.1 This test method is used to test opacity of paints. Several drawdown bars having different aperture sizes are used.