Browns generally owe their color to oxide of iron. Raw umber is a clay similar to ochre colored by oxide of iron. The best comes from Turkey; it is very durable both in water and in oil; does not injure other colors when mixed with them.
Purple Brown is of a reddish-brown color. It should be used with boiled oil and a little varnish and driers for outside work.
Burnt Sienna is produced by burning raw sienna. It is the best color for shading gold.
Brown Pink is a vegetable color often of a greenish hue. It works well in water and oil, but dries badly, and will not keep its color when mixed with white lead. Spanish brown and brown ochre are clays colored naturally by various oxides.
Sepia is a brown pigment, of slightly varying hue, and is obtained from various species of cephalopodous animals. It is a blackish-brown pigment of a very fine texture, mixing well with both oil and water. It is much used by artists, especially for monochrome work. It is a fairly per-
Fig. 16. Kalsomlne Brush, manent pigment, being but little affected by exposure to light and air.
Manganese brown is an oxide of manganese, of a fine, deep, semi-opaque brown, of a good body, and dries well in oil. It is artificially prepared from the waste still-liquors of the chlorine manufacturer by precipitating the liquors with sodium carbonate, collecting the precipitate and calcining in a furnace to a low red heat, until samples taken out and allowed to cool show the desired shade. It is a good and permanent pigment, but it is difficult to use on account of its excessively strong drying properties.