_Orange Russet_, _Russet Rubiate_, or _Field's Russet_. This is a very rich crimson russet with a flush of orange; pure, transparent, and of a middle hue between orange and purple. Prepared from the madder root, it is not subject to change by the action of light, time, or mixture of other pigments. Although not so much employed as the marrone Madder Brown, it is serviceable both as a local and auxiliary colour in compounding and producing with yellow the glowing hues of autumnal foliage, &c.; and with blue, the beautiful and endless variety of grays in skies, flesh, &c. A good glazing colour, its thin washes afford fine flesh tints in water: as an oil pigment it dries indifferently, and requires to be forced by the addition of a little gold size or varnish. Cappah brown and burnt umber sadden it to the rich tones adapted for general use in shadows. So saddened, this lake meets admirably the dark centres of the upper petals of certain fancy geraniums, while alone its pale washes are equally well suited to the lower leaves. 230. MIXED RUSSET. What has been remarked in the preceding chapter upon the production of mixed citrine colours, is likewise applicable to mixed russet. By the immediate method of producing it materially from its secondaries, good and durable colours are obtained by compounding the following orange and purple pigments-- PERMANENT ORANGE. | PERMANENT PURPLE. | Burnt Roman Ochre. | Mars Violet, true. Burnt Sienna. | Purple Madder. Cadmium Orange. | Mars Orange. | Neutral Orange. | Many other less eligible duple and triple compounds of russet are obvious upon principle, and it may be produced by adding red in due predominance to some browns; but these, like most mixtures, are inferior to original pigments. To the orange colours there may be added cadmium red and the orange vermilions, pigments which were classed among the reds, but which contain sufficient yellow to render them adapted for either compound russets or compound citrines. And as of original purple pigments there are two only which are stable, such mixtures as madder red and French blue will help to swell the list of available permanent purples. Rubens' madder itself may be changed in hue by being first mixed with blue and then with orange. * * * * * 231. _Prussiate of Copper_ differs chemically from Prussian blue only in having copper instead of iron for its basis. It varies in hue from russet to purple brown, is transparent and deep, but, being very liable to change in colour by the action of light and by other pigments, has never been much used, and is now obsolete. The compound has the objection of containing free prussiate of potash, not removable by continued washing--sometimes as much as five per cent. * * * * *