THE PROCESSES OF GILDING AND POLISHING.
WOOD GILDING.—The processes of applying gold to wood and to metal are entirely different. In the former the gold, which has been supplied to the gilder in extremely thin layers, generally placed between the leaves of a little paper book to prevent them sticking together, is transferred therefrom to the surface to be gilt, by a dexterous movement of a flat gilder's camel's hair brush, or "tip," as it is termed, the wood having been previously prepared by successive coatings of whitening and thin glue, a thicker body of preparations being required for those parts which are to be burnished. A great deal depends upon the care and time bestowed on the preparation of the work, sometimes as many as ten coatings being given to the wood, and these are successively rubbed down with pumice stone and glass paper, care being taken not to lose the sharpness of carved ornaments. This application of gold leaf is termed mechanical gilding, and is used for gilt furniture, picture frames, or other decorations. Within the last ten years the gold has been applied to the more richly carved furniture in a powder. This preparation of gold is very expensive, costing about £7 the ounce, and is only used for the more costly chairs and couches, etc., generally of old French make, which require re-gilding.
METAL GILDING.—The process of gilding metal which was practised by the mounters of the fine old French furniture described in Chapter VI., consisted in applying to the "ormolu" an amalgam of gold and mercury; the latter was evaporated by heat, and the gold remained firmly adhered to the metal mount, and was afterwards colored as desired, a slightly greenish tinge being effected by such masters as Caffieri, Gouthière, and others. This kind of gilding requires a considerable quantity of the precious metal to be used, and is therefore very costly, but is rich in effect, and, under favourable conditions, permanent. It is, however, very injurious to the workers, on account of the fumes of the mercury poisoning the system; and it has generally been abandoned in favour of the much quicker and far cheaper process of electro-gilding, by which an effect can be produced by an infinitesimal coating of gold. The water gilding process is still used to a moderate extent by the makers of the more expensive reproductions of old furniture in Paris. There is a very cheap and effective process of lacquering which sometimes is termed "gilding," used to give ormolu mounts the color of gold; this is done by applying a solution of shellac and spirits of wine to the metal when heated, and, as with water-gilding, the volatile spirit evaporates and leaves a thin coating of the shellac, which may also be treated so as to have very much the appearance of gold, to the inexperienced eye. It should be mentioned that where mounts are gilt, it is usual to make the material more like the color of gold than ordinary brass would be; this is done by the admixture of a considerable amount of copper, the amalgam being generally termed "or-molu."
POLISHING.—The older method of polishing woodwork consisted in the application of a mixture of turpentine and beeswax to the surface; this would be repeated again and again, and then well rubbed down with a hard brush, when a very durable polish was obtained. For flat surfaces, and particularly for the tops of dining tables which were formerly uncovered to show the wood, oil polishing was the fashion; this was effected by rubbing the table-top with a heavy weight backwards and forwards, using oil as a lubricant. Good housewives used to polish up their dining tables very frequently. Oil polishing had the great advantage, too, of producing a surface which hot plates did not easily mark. The cost, time, and trouble, however, caused these older processes to be abandoned in favour of "French" polishing, which is the application on a prepared surface of shellac dissolved in methylated spirits, and often other ingredients to give poor-looking wood a richer color. This polish is quicker, and therefore, cheaper than the old-fashioned method. It has come into general adoption since the Great Exhibition of 1851.