In watercolor painting to know your pigments is an essential part of painting. Since watercolor is usually painted on paper, and nowadays there is a wide array of colors on offer, its hard to know what to buy. Exposure to light is the major concern as it can cause change over a wide selection of hues.
Watercolors are at most risk as they do not have the protection of the binder enjoyed by pigments bound in oil or acrylic. Many pigments are reasonably lightfast at full strength but fade when in a tint. Watercolors , of course are usually applied in thin films. This exposes the pigment to increased radiation and leads to damage to the color. List of pigments for a basic palette: In 1977 the ASTM (American Society of Testing and Materials) developed standards with new and explicit labeling requirements: Category I (excellent lightfastness) or Category II (very good lightfastness).
IMPORTANT INFORMATION Please take Aureolin off your list of pigments, in the past , I put some swatches of colors exposed to direct sunlight and Aureolin, Windsor and Newton changed drastically. I have been using this transparent yellow for years and was shocked at the results of my test.
Cobalt Blue PB 28
Yellow Cadmium PY 37
Phthalocyanine Blue PB 2
Lemon Yellow PY3
Prussian Blue PB 15
Yellow Ochre PY 43
Viridian PG 18
Cadmium Red PR 108
Phthalocyanine Green PG 7
Scarlet Red PR 188
Chromium Oxide Green PG 17
Quinachridon Red PV 19 , PR 192
Raw Sienna PBr7
Quinachridon Violet PV 19
Burnt Sienna PBr 7
Ultramarine Blue PB 29
Raw Umber PBR 7
Cerulean Blue PB 35
Depending on the manufacturer these are considered Category I and II and the best selection of pigments for watercolor painting.
