Rublev Colours Pigment Alkanet Root - 4 oz

Pigments and dyes are not identical, although there are cases in which the same colouring matter that yields a dye or stain may give rise to a pigment. A pigment is, in fact, a substance that is insoluble in the vehicle with which it is mixed to make a paint, while a dye is soluble.

A lake pigment is a natural organic pigment prepared when a dye has been precipitated on a powdered, colourless, inorganic substrate. The term derives from the Latin word lacca, used in the Middle Ages to denote both lake pigments and the Lac dye. Because of its transparency, aluminum hydroxide is the most commonly used substrate or carrier. Barites, such as barium sulfate, provide an opaque lake pigment.

Often, a mordant, such as tannic acid, lactic acid, or sodium phosphate, is used to fix the dye to the substrate. Madder lake and rose madder, used as artists’ pigments, are prepared from madder extract by adding alum and precipitating with an alkali.

Alkanet is a biennial or perennial herb that grows to 12 inches high. It is similar to borage, with rough leaves, thick tap root and small bright blue flowers in early summer. The name Anchusa is derived from the Greek anchousa for paint, from the use of the root as a dye. The species are hispid or pubescent herbs, with oblong, entire leaves, and bracteated racemes, rolled up before the flowers expand. The corolla is rather small, between funnel and salver-shaped; usually purplish-blue, but in some species yellow or whitish; the calyx enlarges in fruit. The root, which is often very large in proportion to the size of the plant, yields in many of the species a red dye from the rind.

WARNING: this pigment is not considered toxic, but care should be used in handling the dry powder pigment to avoid inhaling the dust.