Yellow Pigments.

Yellow Pigments. For artistic work in oil yellow ochre (see OCHRES), raw sienna (a native earth), cadmium yellow (cadmium sulphide), aureolin (a compound of cobalt and potassium nitrites), lemon yellow (barium chromate), and Naples yellow (basic lead antimonate) are all permanent; but cadmium yellow and aureolin, which require to be carefully prepared, have a tendency to injure a few other colours when mixed with them. Gamboge (q.v.) and Indian yellow (prepared in India from cows' or camels' urine) are beautiful pigments, transparent or translucent, and much used in water-colour painting, but also to some extent as oil-colours. They have both, however, a decided tendency to fade. The other pigments named above are likewise used as water-colours, and are permanent, except Naples yellow, which is unsuited for water-colour painting. Cadmium and lemon yellows are opaque colours, or at least are so to a considerable extent. House-painters use yellow ochre and chrome yellow (chromate of lead) largely. The latter is of a more lively hue than the former, but it is not nearly so durable. Raw sienna is much used for graining painted wood to imitate oak. Yellow lakes, which include brown pink and Italian pink, are beautiful but fugitive colours. They are generally prepared from quercitron bark, but sometimes from Persian berries.