In Dyes, often the names of the dyes confuse us a lot, as one particular dye can be called by many different names. For example, light green dye is popularly known as dye methyl green. This is all because, some dyes are historical and are called by there historical name in certain part of the world, some are named on base of the major group of chemical it is made up of like methyl, nitro etc, where as some are called by the brand name the manufacturers have given it, to avoid the violation of copyrights or trademarks of each other. So, to avoid all this confusion of the dye names, the Color index came into existence.

The color index is a reference database, jointly started by Society of dyers and Colourists and the American Association of Textile Chemists and colorists in the year 1925 at UK. It is available both in form of a book in hard copy and soft copy in the form of CD and is also published on web.

Index ClassificationEach Dye gets identified by a unique five digit number, which is called CI or colour Index number. Apart from the number the each dye is given a Generic name or CI name, the name is based on the base action, dyes mode of behavior and the action. The CI name thus gives a specific way in which dyes can be identified. The CI name is used less as compared to the CI numbers; the CI names are useful in identifying a dye for a particular staining method. As seen in diagram, example of colour index classification by CI name, of one of the blue dye

Hue Indication Chart: These colour terms are used in the Colour Index to provide an approximate idea of the descriptions used in the Shade field of the Colour Index Generic Name records.


Where as the CI numbers are based on the following information:

The colour index numbers are grouped to ranges according to the chemical structure

The following table illustrates the use of the Colour Index for yellow Organic pigment

Facts of Colour Index:

  • The dyes or colours are listed in the Colour Index strictly in accordance with the system of
      • Generic Names
      • Index Constitution Numbers.
  • The extra detailed information about the colorant or dye is put under the reference in the colour Index. The format of information is designed taking into consideration the coloration industry.
  • Around 27,000 individual products are listed under a total of 13,000 Colour Index Generic Names.
  • Popular format has been devised with a unique 'fingerprint' concept.
  • Chemical structures shown are strictly in accordance with the results obtained by modern researches on molecular conformation.

Application of colour index:

The colour index is used by all those who are in the business of colour, starting from coloring on drawing sheets to banner or hoarders on road side, textile, plastics, inks manufactures and also people who people study about colour.

  • Plastics Manufacturers
  • Plastics supplier
  • Paint manufacturers
  • Paint supplier
  • Colorant users, suppliers and manufacturers.
  • Textile manufacturers.
  • Producers of Printing ink
  • Testing labs, Libraries, academic institutions.



Image Courtesy :