This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
Damaskeening, practiced from most ancient times, consists in ornamentally inlaying one metal with another, followed usually by polishing. Generally gold or silver is employed for inlaying. The article to be decorated by damaskeening is usually of iron (steel) or copper; in Oriental (especially Japanese) work, also frequently of bronze, which has been blackened, or, at least, darkened, so that the damaskeening is effectively set off from the ground. If the design consists of lines, the grooves are dug out with the graver in such a manner that they are wider at the bottom, so as to hold the metal forced in. Next, the gold or silver pieces suitably formed are laid on top and hammered in so as to fill up the opening. Finally the surface is gone over again, so that the surface of the inlay is perfectly even with the rest. If the inlays, however, are not in the form of lines, but are composed of larger pieces of certain outlines, they are sometimes allowed to project beyond the surface of the metal decorated. At times there are inlays again in the raised portions of another metal; thus, Japanese bronze articles often contain figures of raised gold inlaid with silver.
Owing to the high value which damaskeening imparts to articles artistically decorated, many attempts have been made to obtain similar effects in a cheaper manner. One is electro-etching, described further on. Another process for the wholesale manufacture of objects closely resembling damaskeened work is the following: By means of a steel punch, on which the decorations to be produced project in relief, the designs are stamped by means of a drop hammer or a stamping press into gold plated or silver plated sheet metal on the side which is to show the damaskeening, finally grinding off the surface, so that the sunken portions are again level. Naturally, the stamped portion, as long as the depth of the stamping is at least equal to the thickness of the precious metal on top, will appear inlaid.
It is believed that much of the early damaskeening was done by welding together iron and either a steel or an impure or alloyed iron, and treating the surface with a corroding acid that affected the steel or alloy without changing the iron.
The variety or damaskeening known as koftgari or kuft-work, practiced in India, was produced by rough-etching a metallic surface and laying on gold-leaf, which was imbedded so that it adhered only to the etched parts of the design.