Cadmium yellow

#F5C518Formula CdSEarliest recorded use 1840s

14 eras34 artists44 colors

The yellow that finally worked. Cadmium sulphide is brilliant, opaque, completely lightfast and mixable with anything, and its arrival ended a search that had run through arsenic, lead and chromium without ever getting all three qualities at once.

Origin

Cadmium was discovered in 1817 by Friedrich Stromeyer, who found it as a contaminant in zinc carbonate. Cadmium sulphide was recognised as a pigment almost immediately but remained rare and expensive until the 1840s, when the metal became available as a by-product of industrial zinc refining — cadmium has essentially no ore of its own and is still obtained this way. Varying the manufacture, and substituting selenium for some of the sulphur, produces a continuous range from pale greenish lemon through deep yellow and orange to a full red, all chemically related and all sold under the cadmium name.

In art history

It reached artists in the 1840s and was in general use by the 1860s, appearing in twelve eras here. Monet, Van Gogh, Matisse and the Fauves used it, and it is the yellow of most twentieth-century painting, from Bonnard to Rothko to the flat saturated fields of Pop. Its historical significance is that it removed a constraint: for the first time a painter could use a brilliant yellow in any mixture, in any medium, without worrying that it would blacken the lead white next to it or fade in ten years or poison the person applying it in the way orpiment did. Everything painters had learned about working around their yellows became unnecessary.

In the studio

Opaque, strong, and slow-drying in oil — the one respect in which it is inconvenient, since heavy cadmium passages stay soft for a long time. It is completely lightfast, stable in mixtures, and unaffected by other pigments, though the older, poorly washed grades could contain free sulphur and cause problems with lead and copper colours; modern manufacture does not. It is not stable in fresco, being attacked by lime. Its toxicity is real but modest in the studio: cadmium compounds are toxic and carcinogenic, but the sulphide is very poorly soluble, and the practical risk is from inhaling the dry pigment rather than from handling the paint.

Afterlife

Still the standard, still expensive, and periodically under threat. The European Union has considered restricting cadmium pigments several times, primarily over concerns about wastewater from artists washing brushes, and each proposal has produced vigorous opposition from painters and manufacturers arguing that the environmental contribution is negligible and the substitutes inferior. Azo and benzimidazolone yellows match the hue and are cheaper and non-toxic, but they are transparent and weaker in tint, and for opaque work cadmium remains unmatched.