Composition and Permanence: The colour index name is established and published by the American Association of Textile Chemists and Colourists and The Society of Dyers and Colourists. The colour 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 particular colour space, it does not provide definitive information. Many pigment grades with an extensive range of physical attributes are available from several manufacturers.

Chemical Name: The chemical name is a brief, commonly used generic type designation of the pigment type composition. In conjunction with the colour index name, the chemical name can broaden the artist's understanding of the source and nature of the pigment used.

Lightfast Rating – Permanence: The permanence of a colour is a measure of the lightfastness of the pigment when dispersed in a vehicle and subjected to conditions which emulate the exposure usually given to a fine arts object. Such ratings are generally considered vehicle or media-dependent and can vary between media — thus, pigment, which is suitably lightfast for oil colour might not be lightfast in watercolour. Our ratings utilize historical data, accelerated testing and data from pigment manufacturers to establish one of the most demanding standards among artists’ colour makers today.

Opacity Rating - Transparency and Opacity: Each of our colours has a designation indicating relative degrees of transparency to opacity. Please consider these as a guideline because any thin film application, while not necessarily transparent, can be interpreted by the view as such.