=The Scraper= being regulated so that it will give a sufficient pressure, pass the bed quickly through the press to the extent necessary to produce a complete impression. The length of traverse of the bed during printing can on most presses be regulated by side screws, or the tympan may be lightly marked. After releasing the pressure, the bed is withdrawn, the tympan and masking frames thrown back, and the printing paper cautiously raised by one corner. It often adheres slightly to the printing surface, and this is usually an indication of a good plate. The adhesion may, however, at times be so strong as to tear the paper, or, in the case of enamel paper, remove the chalk coating. As previously mentioned, the scraper should be selected of a width somewhat exceeding that of the picture, but never exceeding that of the glass plate. It may be left plain and moderately sharp, or covered with leather. =Damping the Plate= between each impression will usually be unnecessary, providing a good sample of gelatine is used, and the damping solution contain a sufficient quantity of glycerine. In cases where the Collotype plate has been over exposed, or the subject be one which requires an absolutely white background, damping between each impression will be absolutely essential. Where it is omitted for any length of time, the whites of the pictures will always be more or less degraded or tinted. Should the early impressions not be satisfactory, patience should be exercised, and by careful treatment with the roller or rollers, and care in the damping, favourable results will often ensue after the first few impressions have been pulled. Only from actual damage to the print layer, or excessive over exposure in the copying frame, need the plate be placed aside as in a hopeless condition. The beginner should guard particularly against mechanical damages in damping; drying and rolling. Lithographers are inclined to treat the delicate printing surface with the same vigour and energy that they would apply to the more substantial lithographic stone to which they are accustomed. The following directions from “Kleffel’s Manual of Photography” are to be recommended in printing line subjects, particularly in “glass” printing direct from the negative:—“The chromated layer of gelatine must have been submitted to a sufficiently long exposure to ensure it taking the ink over the whole surface. For the first rolling in of the plate, the ink should be composed as follows: White wax, 45 parts; middle varnish, 5 parts; gum elemi, 15 parts; litho ink (about 5s. per lb.), 20 parts.