PAPER-HANGINGS. This name is applied to the webs of paper, papiers peints of the French, usually decorated, with which interior walls are often covered. Previous to the invention of the paper-machine, sheets of paper of the size called elephant, 22 by 32 inches, were pasted together, to make 12-yard lengths, before the pattern was imprinted; but this is now rendered unnecessary by the facility of making webs of any length. Upon the paper it is usual first to spread a ground-color, with proper brushes, taking care to produce a perfectly smooth surface. The colors employed are opaque, and are mixed with size, and sometimes also with starch, and most of the ordinary pigments are used. In the early stages of the art, it was usual to have the patterns stenciled (see STENCILING) on the ground-color. The stenciling plates were usually pieces of paste; board, one being required for every differently colored portion of the pattern. After wards, wooden blocks were adopted, similar to those used in calico-printing, made of pear or poplar wood, generally the width of the paper, forming, indeed, huge wood cuts, on which the pattern is in high relief. As many blocks are required as there are colors in the pattern, each bearing only so much of the pattern as is represented by the color to which it is assigned. Of course, the whole beauty of the work depends upon the nice adjustment of one portion of the pattern to another ; and this is determined by guide-pins in the blocks, which are so managed as not to disfigure the surface with their points. The pattern-block, being coated with its particular color from the color-tub, is laid on the paper, which is stretched out for the purpose on a table, and a lever is brought to hear upon it with sufficient pressure to make the whole of the block hear equally upon the paper. When one block has been printed the whole length of the paper by a succession of impressions, the piece is taken to the drying-room, and dried, previous to receiving the next color; and it often happens that the same operations have to be repeated a dozen different times before the pattern is completed. This process is now being rapidly superseded by the cylinder printing-machines, which are of the same kind as are used in printing textile fabrics. In these machines, the pattern is engraved
on a series of copper cylinders, and each part or color has a separate cylinder, and an arrangement for keeping it constantly supplied with color when working. The cylinders are so arranged as, by the sum of their revolutions, to make the pattern complete; so that as the web of paper passes the first, it receives the color for one portion of the pattern, and reaches the second in exact time to have the next color applied in the right places. In this way the entire piece only occupies a few seconds in receiving the complete dec oration.
The polished or glazed papers have the ground prepared with gypsum or plaster of Paris, and the surface dusted with finely-powdered steatite, or French chalk. When per fectly dry, this is rubbed hard with a burnishing-brush, until the whole is evenly polished. This is generally done before the pattern is printed, but in some cases pattern and ground are both polished. In making the flock-papers, the printing is done in the same way as in the block-printing, only, instead of colored material, a composition called encaustic is printed on. It consists of linseed-oil, boiled .with litharge, and ground up with white lead; sufficient litharge is used to make it dry quickly, as it is very adhesive. The lock is prepared from the shearings of woolen cloths from the cloth-mills, by washing and dyeing the shearings to the various colors, then stove-drying- and grinding them in a peculiar mill, which, in their brittle state, after leaving the stove, breaks them OW. After this they are sifted, to obtain various degrees of fineness.. By nice management, the prepared flock is so sprinkled over the whole of the printed surface as to coat the encaustic, and adhere evenly and firmly to it. The same adhesive material is used for printing in gold and other metals. The pattern being printed with the encaustic, gold or other metallic leaf is applied, and when it is properly fixed, the loose metal is brushed away with a hare's foot or other soft brush. Some of the finest French papers have much of the pattern actually painted in by hand, a process which, of course, renders them very costly.