Bookbinding and the Conservation of Books
A Dictionary of Descriptive Terminology

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lake

A term used with reference to any of a large group of organic pigments that are generally bright in color and are more or less translucent when in the form of an oil paint. Lakes are obtained by precipitating dyestuffs and other coloring matters, e.g., cochineal, madder, logwood extract, etc., onto a substrate in the presence of tannic acid, casein, sodium phosphate, etc., or with a metallic hydroxide. Aluminum hydroxide, for example, reacts with many soluble organic coloring matters, precipitating them as so-called lakes in cloth printing and dyeing, with the hydroxide acting as the mordant; the same dye, however, can produce different colored lakes depending on the mordant employed. Because many salts of calcium, chromium, magnesium, tin, zinc, etc., are used in producing lakes, a great number of pigments can be obtained. Substrates used include alumina, which gives a pigment that is rich and transparent in color, such as those used in printing inks; china clay, where a light, soft material with bulk and good suspension properties is required; barytes, which are used in the manufacture of paint; blanc fixe, which is usually a more finely divided baryte than the natural crystalline ones; and green earth and precipitated hydroxide of iron, which are used according to color requirements.

Many excellent pigments having good light fastness are now made from artificial dyestuffs; therefore, because they are expensive and/or insufficiently light fast, many lakes formerly produced from natural dyestuffs are no longer in demand.

The term "lake" may derive from the Italian "lacca," used by medieval Italian craftsmen to indicate the scum they removed from their dye vats and sold to painters. The Italian word, in turn, is related to "lac," which derives from the Sanskrit. See: LAC . (17 , 195 )




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