To set New Tapes.—Pass the tape around and close to the cylinder. Lap it over one of the tape pulleys, and then pass it around the small guide pulley on the shaft above. To increase its tightness, throw up the guide pulley from the shaft, and set the binding screw more tightly. All these pulleys are movable on their shafts, and distance between them may be altered at pleasure. Let the tapes rest upon the outer margin of the sheet, and see that the overlays on the tympan over which the tapes pass are of equal thickness; if not of equal thickness, the sheet will wrinkle.
To set the Fly.—Run through a sheet of the paper to be printed, and let it run down the fly so far that it is barely held by the fly pulleys. Then set the cam which works the fly, so that its point just clears the small friction roller on the shaft, and it will throw down the sheet correctly. Tighten the spring according to the size of the sheet, and set the spring crank so that it will prevent the fly from striking too hard on the table.
It will be seen that good presswork does not depend entirely upon the press, nor yet upon the workman or the materials. Nor will a superiority in any one point compensate for a deficiency in another: the newest type will suffer from a poor roller, and the most careful making-ready will be of no avail if poor ink is used. It is necessary that all the materials should be of the best kind,—that they should be well adapted to each other, and fitly used. Although a good workman can do much with insufficient materials, there are cases where a neglect to comply with one condition is equal to a neglect of all.[19]
FINE HAND-PRESSWORK.
Fine presswork is the art of printing perfect impressions from the surface of type or engravings in relief: that is, the subject transferred to paper should be an impression from the surface, and the surface only, of the types or engraved lines, of such a tone as to produce all the effect of which the subject is capable, without either superfluity or deficiency of colour.
The press ought to be in the best condition; otherwise it will be impossible to get an equal impression without much trouble and loss of time. The joints of the tympan should not have any play, or the correctness of the register will be affected, and slurs and doubles be caused.
The parchments on the tympans should be thin, and of a uniform thickness, and stretched on the tympans so as not to be flaccid. On account of its thinness, smoothness, and uniformity, silk is probably preferable.
The face of the platen ought to be a true plane, and parallel to the press-stone, or table.
The advantage of having a good press is unavailing for the production of fine work if the types are much worn; for it is impossible to produce a sharp, clear impression when the type is worn and the fine lines are rounded by much use. In consequence of this roundness of the letter, it is necessary to use a thick blanket in the tympan to bring up the type; thus producing a gross and irregular impression of more than the surface.
Ink for fine work should be characterized by the following peculiarities:—