=The Preparation of the Plate= for the machine is identical with its preparation for the hand-press, but greater uniformity, both in the negative, exposure, and etching, are demanded than by the hand-press. For the latter considerable latitude is permissible, as the intelligent printer may, by varying his rollers, his rate of rolling and other little dodges, produce perfect impressions from plates which would, under the entirely mechanical action of the machine, fail lamentably. =Adjustment of the Rollers= is so effected that they are lifted about 2 mm. when passing over the inking slabs and the printing plate; if a greater lift is necessary to bring them upon the printing surface marks will be produced upon the plate, and if arranged for a less lift they will probably skid over the plate, damaging the printing surface. They should also be adjusted perfectly parallel with the surface of the inking tables, or one side only may come in contact with the work. =Fixing the Plate= to the bed of the machine is effected in several ways, but usually with small clips, as described for the hand-press. All adhering gelatine, etc., must be removed from the plate, and a thin sheet of white paper inserted between it and the bed of the press. The faces of the metal clips must be protected with strips of leather, cork, or some such elastic bodies, otherwise the pressure exerted would cause the glass to fly. A straight edge is placed across the machine, and the bed lowered by means of inclined planes attached to suitable gearing until the surface of the plate is well below the circumference of the cylinder, and from this position it is brought up to its proper level, raising each side equally, that the pressure may be perfectly uniform.