=The Press= is an indispensable requisite for printing operations. There are small wooden hand-presses, especially constructed for collotype, which may be purchased at a very low price—£4 to £5; but the more economical way is to procure a small lithographic press constructed of iron. This will not only be found more durable, but it may, if occasion arise, be used either for lithographic or zincographic printing, as it will bear the necessary pressure, which is greatly in excess of that applied in collotype printing. The hand-press constructed by Sutter is a form that may be strongly recommended. If the output of prints is to be large, a steam machine will be necessary, the cost of which will be not less than £200 to £250. Fig. 6 represents a press which has been largely used for collotype. =D= is the bed or carriage upon which the plate is fixed in the manner described further on. By turning the crank handle =C= the bed is carried under the scraper, which is secured in the scraper-box =A=. The scraper is kept in position by the lever =B=. The scraper-box is represented as closed down in the illustration, but in actual practice it would not be in the position shown until the tympan-frame =E= had been lowered. =The Tympan=, of either leather or thin sheet zinc or brass, is marked =F= in the illustration. All iron portions of the press subject to friction should be frequently cleaned and carefully oiled with a good machine-oil. [Illustration: _Fig. 6._] =The Scrapers= should be of either pear tree, lime, maple, or preferably box, with a blunt bottom edge, which should be planed true, and finally finished by rubbing on a sheet of glass-paper placed upon a perfectly flat surface. They must be adjusted with even more precision than is necessary in lithography, as owing to the difference in the printing surface, the same pressure cannot with safety be applied. With plates or stones of large size it will be found that the pressure of the scraper will be unequal, greater pressure being exerted in the centre than upon the edges of the printing surface. Many printers, to counteract this tendency, slightly scrape away or hollow out by means of a piece of glass the centre of the scraper. With sufficient pressure and plenty of elastic packing between the printing paper and the tympan, this slight difference may be easily overcome. Several scrapers should be provided of various lengths, so that one of suitable size may be always available to suit the particular work in hand. It should always be slightly longer than the width of the picture, but shorter than the width of the stone or plate. By pressing the edge of the scraper to the surface of the latter and looking towards a window no light should be visible between the two surfaces. If the edges of the scraper are carefully rounded, it may be covered with a strip of wash-leather,[G] smooth side outwards, and secured by means of tacks,