Exceptionally lightfast colors are obtained with metal-complexed azo dyes. Copper complexes of o, o’ — disubstituted azo compounds produce a wide range of colors (yellow, ruby, violet, blue, brown, olive, black).
3.1.1.2 Anthraquinone Dyes [38]
Anthraquinone-based dyes are significant because of their brilliance, good lightfastness, and chromophore stability under both acidic and basic conditions. Until quite recently they dominated the market for brilliant blue reactive dyes in spite of their relatively low color strength (e ca. 15 000) and comparatively high cost. The shades of commercial reactive anthraquinone dyes range from violet to blue, e. g., C. I. Reactive Blue 19 (17). Almost all the important dyes are descendants of “bromaminic acid”. This is treated with a reactive amine component, whereby the reactive group may be linked to the amino group by way of various aliphatic or, more often, aromatic bridging units.