These are terms used to designate those leathers, whether of the ox, the horse, the calf, or the seal, which are finished with a waterproof and bright varnished surface, similar to the lacquered woodwork of the Japanese. The term "enamelled" is generally used when the leathers are finished with a roughened or grained surface, and "atent" or"apanned " are the terms us when the finish is smooth. Though generally black, yet a small quantity of this leather is made in a variety of colours.
(1) Leather destined to be finished in this way requires to be curried without the use of much dubbing, and to be well softened. The English practice is to nail the skins, thus prepared and quite dry, on large smooth boards, fitted to slide in and out of stoves maintained at a temperature of 160° to 170° F. (71° to 77° C), coating them repeatedly with a sort of paint composed (for black) of linseed-oil, lampblack, and Prussian blue, well ground together. Each coating is allowed to dry in the stoves before the next is applied. The number of coatings varies with the kind of skin under treatment, and the purpose for which it is intended. The surface of every coat must be rubbed smooth with pumice; finally, a finishing coat of oil varnish is applied, and, like the preceding coats, is dried in the stove. The exact degrees of dryness and flexibility, the composition of the paint, and the thickness and number of the coats, are nice points, difficult to describe in writing. This branch of the leather industry, so far as it relates to calf-skins, is carried on to a larger extent, and has been brought to greater perfection, in Germany and France than in England. In the former countries, the heat of the sun is employed to dry some of the coatings.
The United States have also brought this style to a high degree of excellence, especially in ox-hides. There, use is made of the oils and spirits obtained from petroleum, and without doubt French and German emigrant workmen have materially assisted in attaining this high standard. Leather finished in these styles is used for slippers, parts of shoes, harness, ladies' waist-belts, hand-bags, etc, and has now maintained a place amongst the varieties of leather for a long period of years. (Spoils' Ency.)
(2) The first coats of the japan for patent leather are made with linseed-oil and Prussian blue, boiled together for some hours; the last coat or varnish, with linseed-oil and lampblack, limilarly boiled. Each coat is separately dried at a temperature of 160° to 180° F. (71° to 82° C), and rubbed on the leather by the hand, the skin being nailed on to the surface of a board. As the process is a very delicate one, and requires special knowledge in each part of the operation, it would be useless for any one to attempt to produce japanned leather, except as an experiment, for his own amusement, without serving an apprenticeship to the trade. (Bevingtons & Sons.)
(3) To Separate Sides Of Patent Leather
Patent and enamelled leather will, if the glazed sides are placed together in warm weather, become stuck together, and unless carefully separated, the leather will be spoiled. The simplest and best way to separate sides is to place them in a drying or other hot room; when hot, they can be taken apart without injury to the glazed or enamelled surface. If a drying-room is not accessible, lay the sides on a tin roof on a hot day, and they will soon become heated sufficiently to allow their being separated without injury. Any attempt to separate without heating to a high degree will prove a failure.
(4) When the enamel of the leather has chipped off, clean the parts well with fullers' earth and water, and then apply varnish. In the first manufacture, the primary coat is made of pale Prussian blue and the best drying-oil, boiled together. When cold, a little vegetable black is ground up with it, and after application to the leather, it is stoved at a gentle heat, and polished with a piece of fine pumice; a second coat, which consists of the same varnish with some pure Prussian blue mixed with it, is then applied. There are also third and fourth coats applied, the last being made of 2 oz. pure Prussian blue, 1 oz. vegetable black, 1 qt. drying oil, with a little copal or amber varnish. Each coat is stoved, and rubbed with pumice. For the purpose of repairing, use all " last coat," stoving at a heat not exceeding 160° F. (71° C.); but take care that the pigments are carefully ground in the drying-oil, and don't add the amber varnish till the third and last coat.