If numerous glass-head pins are to be put into a map at one time, the eraser in the end of a lead-pencil should be used to push the pins down until the heads touch the map. Pins can be very quickly located if only their points are pushed into the map by hand, leaving the main pressure to be applied by the lead-pencil eraser after a number of pins have been located. The pencil-eraser method saves time and it also eliminates the discomfort which may be caused if thousands of pins are pushed into a map by using the thumb and forefinger only.

Line cuts, sometimes called zinc cuts, may be made directly from pin maps if glass-head map pins of suitable color are used. At the point on the map where each pin head is located there will be a black dot on the print made from the zinc cut. As light is reflected from the surface of the glass heads of the pins, there are sometimes shown in a photograph high lights which must be retouched with a pen or a fine brush so that the whole spot shall be black, rather than black with a white center, as seen in Fig. 191. Anybody can do this retouching very quickly. It is mentioned here only as a caution that the photograph be inspected before the zinc engraving is made from it.

MAPS AND PINS

Photographs for hne cuts must have a good contrast of white and black, or colors which photograph as black. Photographs or original drawings containing shades of gray will not produce good line cuts and frequently cannot be used at all for the zinc engraving process. When line cuts are to be made from pin maps it is best to be certain that the glass-head pins are selected in colors which will photograph as black.