Why can one colorant have many different trade names?

The existence of many trade names for a single colorant is primarily a result of commercial branding and the way the industry manages nomenclature. While the Colour Index (C.I.) assigns a generic name to all colorants that share the same chemical structure, these products are not necessarily identical in terms of particle size, crystal structure, or the presence of additives and impurities.1

Because manufacturers are free to create their own trade names for a given colorant, the number of commercial names has grown to exceed 50,000, even though there are far fewer unique chemical structures. Additionally, many dyes have been in use since long before the first Colour Index was published in 1924, and their original or "classical" names remain in wide circulation alongside newer commercial designations. This system allows companies to market specific formulations tailored for diverse end uses, such as textiles, plastics, or printing inks, while maintaining their own brand identity.21