The definitive
classification of
dyes & pigments.
A century of colourant research, curated by the Society of Dyers and Colourists. 27,400+ generic names, 140,000+ commercial products, 840+ manufacturers — searchable by structure, hue, fastness and use.
A shared language for colour, maintained since 1924.
The Colour Index pairs each dye or pigment with a Generic Name (CIGN) and Constitution Number (CICN). Manufacturers register their commercial products against those fingerprints — so formulators, researchers and regulators speak precisely about the same colourant.
How classification worksA use-and-hue generic name: Acid Red 27. Describes the colourant family, not a vendor.
Five-digit number tied to the molecular structure. Acid Red 27 → 16185.
Branded formulations registered against a fingerprint, with SDS, technical data and fastness.
Retired names, alternative numbering and historical notes — preserved alongside the live catalogue.
Annual subscription. £37 per user.
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