Composition and Permanence
The color index name is established and published by the American Association of Textile Chemists and Colorists and The Society of Dyers and Colourists. The color index name is a generic category and does not refer to a specific pigment. While it enables the artist to form a general idea of opacity, transparency and lightfastness, for a pigment in a certain color space, it does not provide definitive information. Many grades of pigment are available from a number of manufactures with a very wide range of physical attributes.
The chemical name is a brief, commonly used generic type designation of the pigment types composition. in conjunction with the color index name, the chemical name can be used to broaden the artists understanding of the source and nature of the pigment used.