The materials used in printing are equally simple.
Paper.—Bibulous paper of various qualities and degrees of thickness is chiefly made from the Broussonetia papyrifera. The sheets are moistened with water before the printing begins, the amount of fluid employed varying with the quality of the paper. A single wet sheet is put between every three or four dry sheets until a suitable layer is formed, and this is then pressed between two wooden press boards until the whole has a uniform and proper degree of moisture. This can only be adjusted by care and experience, and it is essential to the success of the print, since the water colours used for printing tend to spread in the absorbent paper, and a small excess of moisture would inevitably ruin the impression. The sheet is printed on one side, and the leaf is made by folding, so that each leaf is double.
In éditions de luxe a very thick soft paper is employed, but in ordinary volumes it is much thinner, often so thin that the design on the other side of the folded sheet is more or less visible. In one volume (dating back to about 1700) in the British Museum Collection, the illustrations are printed on both sides of a heavily enamelled sheet. This is perhaps unique in Japanese printing. For colour-printing the paper is specially prepared by treatment with dosa, a kind of size, to prevent the tints from spreading.
Silk is occasionally, but rarely, used in place of paper.
Colours.—These were almost identical with the colours used by the painter, and were mixed with water and rice paste. Many were of native origin, others were imported from China, and in later years the European market has been utilised with disastrous results.
Black is Japanese ink. In the older prints this was commonly of a somewhat grayish tint; but a deep black was used by Toyokuni in his latest period, and appears in many of the modern broadsides. A black prepared from soot of pine-wood was also used in cheap prints.
White.—To no tsuchi, a carbonate of lead prepared in Japan. It is not often used alone, as it is apt to blacken on exposure. Gofun is a kind of white made by powdering calcined oyster shells.
Red.—There are many kinds of reds used by the printers, (1) Béni, a very pale pink, extracted from a kind of safflower called kijomé. It is said to have been the earliest colour print used in the