EMBOSSING, the art of producing raised figures upon various substances, such as paper, leather, wood, metals, etc. This is usually effected by pressing the substance into a die, the kind of die and mode of applying the pressure being modified accord ing to the nature of the design and the properties of the substance to be embossed. Sheet-metal is embossed by stamping it between a pair of steel dies, one in relief, the other in intaglio. See DIE-SLNEING. When the pattern is a deep one, several pair of dies are used, and several blows given with each, the metal being occasionally annealed. The first stamping produces a crude resemblance to the final design, of moderate depth; successive stampings bringing up more of the details, and giving increased depth. The upper die is usually raised by a rope attached over a pulley to a stirrup, in which the workman places his foot; he draws his foot down to raise the heavy die to the required height, and then suddenly releases the pressure of his foot from the stirrup, when the die descends by its own weight. While thus raising the die with his foot, he adjusts the work in its place with his hands. Smaller work is embossed with a screw-press, the lever of which is turned with one hand, while the work is placed under the dies and removed by the other. Paper and card are embossed in a similar manner, but the dies are frequently of brass, sometimes of copper electro deposits, suitably backed. The counter-die is commonly made of soft metal, card or mill board, pressed into the metal intaglio die until a sharp impression is produced. The paper or card is well damped, and a fly-press is generally used. The leather or cloth for bookbinding is embossed in this manner, the counter-die being usually made by gluing.several pieces of mill board together, and gluing them to the upper bed of the press, then stamping these into the lower die until a perfect impression is obtained. The embossing press designed and constructed by Mr. Edwin Hill, for impressing the medal lion upon postage envelopes, is a very elaborate and beautiful machine, which inks the die itself, and with the aid of two boys, to place and remove the envelopes, embosses sixty envelopes in a minute. When large surfaces of textile fabrics, such as table
covers, etc., have to be embossed, the fabric is compressed between rollers, one being of metal, upon which the device is sunk like a die; the counter-roller or bed-cylinder is of paper covered with felt; this yields sufficiently to allow the fabric to be pressed into the die-cylinder. A third smooth metal roller is commonly used to press out again the impression made upon the bed-cylinder; this acts upon the bed-cylinder on the side from which the fabric emerges. Paper is sometimes embossed in this manner; and the flat ting roller may be dispensed with if the cylinders are sufficiently accurate iu their diam eters for the pattern always to fall on the same place at each successive revolution. Leather embossed in high relief has been used for ornamental purposes in place of wood carving, on picture-frames, cabinet-work, etc. The dies are of type-metal or electro deposits, and the leather is softened or fulled, i.e. worked with water till it contracts and thickens, then it is pressed into the dies by suitable round pointed tools, like model ing tools, made of wood, hone, or copper. When dry, the leather is removed from the molds, and by its elasticity and shrinking it will relieve from very deep and undercut designs.—Mr. Straker's mode of embossing wood differs from all the above, and is very curious and ingenious. When wood is pressed and rubbed with a blunt instrument, the surface yields, and a depression of some depth may be made in it; if the wood be now soaked in water, the depressed portion will rise again to its original level. Mr. Straker takes advantage of this property thus. He rubs down the surface in those parts that are to be finally in relief, he then planes or shaves away the uncompressed portions until the bottom of the depressions are reached and made level with the new surface; the wood is then soaked; the compressed parts rise to their original level, and, of course, in doing so, rise above the portions that have been planed away, and present the required device in relief.