JAPANNING is the art of coating surfaces of metal, wood, &c., with a variety of varnishes, which are dried and hardened on, by means of a high temperature, in stoves or hot chambers, which drying processes constitute the main distinguishing features of the art. The trade owes its name to the fact that it is an imitation of the famous lacquering of Japan, although the latter is prepared with entirely different materials and processes, and is in all respects much more brilliant, durable, and beautiful than any ordinary japan work. Japanning is done in clear transparent varnishes, in black, and in body colours ; but black japan is the most characteristic and common style of work. The varnish for black japan consists essentially of pure natural asphaltum with a proportion of gum animd dissolved in linseed oil and thinned with turpentine ;.but there are numerous receipts given for the varnish, and manufacturers generally conceal the composition of their own preparations. In thin layers such a japan has a rich dark brown colour, and only shows a brilliant black in thicker coatings. For fine work, which has to be smoothed and polished, several coats of black are applied in succession, each being separately dried in the stove at a heat which may rise to near 300° Fahr. Body colours consist of a basis of transparent varnish mixed with the special mineral paints of the desired colours or with bronze powders. The transparent varnish used by japanners is a copal varnish which contains less drying oil and more turpentine than is contained in ordinary painter's oil varnish. By japanning a very brilliant polished surface may be secured which is much more durable and less easily affected by heat, moisture, or other influences than any ordinary painted and varnished work. Japanning may be regarded as a process intermediate between ordinary painting and enamelling. It is very extensively applied in the finishing of ordinary ironmongery goods, and domestic iron work, deed boxes, clock dials, and papier mache articles. The process is also applied to blocks of slate for making imita tion of black and other marbles for chimney pieces, &c., and a modified form of japanning is employed for prepared enamelled, japan, or patent leather.
The beautiful lacquer work of Japan owes its hardness and durable qualities solely to the natural varnish which forms the basis of the lacquer. That varnish is simply an exudation from a tree (Rleus vernieifera) cultivated for the sake of this product throughout a wide area in Japan. The varnish is obtained by making incisions in the bark of the tree, from which a mingled clear and milky juice flows abundantly, which on exposure quickly darkens and blackens in colour. After resting in tubs for some time the juice becomes thick and viscuous, the thicker portions settle at the bottom of the vessel, and from it the thinner top stratum is separated by decanting. Both qualities are strained to free them from impurities, and when ready for use they have a rich brown-black appearance, which, however, in thin layers presents a yellow transparent aspect. This varnish when applied to any object becomes exceedingly hard and unalterable, and with it as a basis all the coloured lacquers of Japan are prepared. The black variety of the lacquer is prepared by stirring the crude varnish for a day or two in the open air, by which it becomes a deep brownish black. Towards the completion of the process a quantity of highly ferruginous water, or of an infusion of gall nuts darkened with iron, is mixed with the varnish, and the stirring and exposure are continued till tile added water has entirely evaporated, leaving a rich jet black varnish of proper consistence. In preparing the fine qualities of Japanese lacquer, the material receives numerous coats, and between each coating the surface is carefully ground and smoothed. The final coating is highly polished by rubbing, and the manner in which such lacquered work is finished and ornamented presents endless variations. The durability of Japanese lacquer work is such that it can be used for vessels to contain hot tea and other food, and it is even unaffected by highly heated spirituous liquors.