Page:Cyclopedia of Painting-Armstrong, George D (1908).djvu/167

Rh are beaten to extreme thinness, the malleability and ductility of the metal allowing as many as 2,500 leaves, 3 inches by $3 1/4$ inches, to be obtained from 1 ounce of fine gold, or to put it in another way, the total thickness of 300,000 leaves is less than 1 inch. Gold leaf is usually put up in books of 25 leaves, each leaf being $3 1/4$ inches square. It is sold by the 1,000 leaves—viz., 40 books. Silver leaf is usually 4 inches by 4 inches, and metals are made in both sizes, and larger.

Gold leaf is termed white, pale, medium, deep, extra deep, citron, red, etc., according to its color. Gold is readily damaged in the book by handling, damp, and shaking, for this reason good gold leaf of recent make should be selected. The best work cannot be produced by any other. It should be kept in a dry place, and may, with advantage, be placed upon a hot plate, or in the oven prior to using. The red powder on gold books is put on to prevent the gold sticking to the leaves of the book, it is bole, a red earth from Armenia, of peculiarly flaky, smooth, and soft texture. A red French clay is sometimes used for the same purpose.

Methods of Gilding. The various methods of applying gold leaf used by painters and decorators are termed: Oil gilding, Japan gilding, and Water gilding.

These methods vary in detail upon different kinds of grounds. Oil or Japan gilding is used upon painted surfaces, or grounds that have been strongly sized or varnished.

Oil Gold Size. Oil gold size is a preparation of fat linseed-oil, which has, by exposure to the atmosphere, lost its power of absorbing oxygen, and become viscid and less hard drying, it may be prepared by exposing linseed oil to the air and light in a wide, open-mouthed vessel for about six months. To make it usable and give it a little body and color, ochre is ground up in about one-third of the whole quantity and added to the whole bulk, a little driers, usually litharge, is also required, and, if too thick for use, it must