Within the international English system, the so-called Colour index, each pigment is indicated with a pigment name and pigment number.
This makes it possible to ascertain which pigments are incorporated in certain colours as well as the chemical composition and properties of those pigments. It is mainly the pigment names that are of interest to the artist.
Example: PW = Pigment White
PW4 (pigment name) = zinc oxide - 77947 (pigment number)
PW - White pigments PW6 - Titanium white
PY - Yellow pigments PY35 - Cadmium yellow
PO - Orange pigments PO34 - Azo orange
PR - Red pigments PR112 - Naphthol red
PV - Violet pigments PV19 - Quinacridone rose
PB - Blue pigments PB29 - Ultramarine
PG - Green pigments PG7 - Phthalo green
PBr - Brown pigments PBr7 - Natural umber
PBk - Black pigments PBk11 - Oxide black