Wall-paper. For ordinary purposes this consists of a tough, but not a thick paper, printed with a pattern in size colours. For expensive wall-papers a rather stout paper is used, and for very cheap kinds a paper of such poor quality that it can only be pasted on walls without tearing by great care. The printing of the commoner kinds is done with a roller printing-machine something like that used in Calico-printing (q.v.), but the better class of wall-papers are block-printed by hand. The printing rollers or blocks are either entirely of wood, in which case the pattern is cut on their surface, or they are of wood faced with a pattern formed of felt, and outlined with thin brass fixed edgewise into the wood. Flock-paper, sometimes called velvet-paper, is made by printing the pattern in strong size, and then dusting this over with ground wool dyed various colours, and called 'flock.' The superfluous flock which does not adhere to the size is then shaken off. Flock-papers so made have a rich effect, but for some time past most of them have been prepared in one colour, and painted over after being put on the walls. In the latter case they in some degree imitate embossed leather. Such parts of a pattern as are to be finished in bronze or gold leaf are first printed in gold size. Embossed Japanese wall-papers entirely coated with bronze, but with the sunk portion of the pattern printed in colour over the bronze, are now much used in Great Britain. These are varnished, and therefore admit of being washed. The Japanese use powdered mica or talc to give paper a silvery appearance.
The modern system of paper-hanging, which is so far an imitation of the older manner of decorating walls with figured textile fabrics or embossed leather, came into use in Europe after the paper-making machine was brought into practical shape in the beginning of the 19th century. Before that paper could only be obtained in sheets of limited size, which were, however, to some extent used for covering walls after a pattern had been put on them. The Chinese appear to have used wall-papers for centuries.
In the later decades of the 19th century the patterns on wall-papers have, as a rule, been greatly improved, some of the best decorative artists in England and France having been frequently employed in designing them. It is hardly necessary to say that no plastered wall should be papered, except with plain cartridge paper, until it is thoroughly dry. See EMBOSsing.