COPPER PATINIZING AND PLATING: See Plating.
COPPER POLISHES: See Polishes.
COPPER, SEPARATION OF GOLD FROM: See Gold.
COPPER SOLDER: See Solders.
COPPER VARNISHES: See Varnishes.
COPYING PRINTED PICTURES.
The so-called “metallic” paper used for steam-engine indicator cards has a smooth surface, chemically prepared so that black lines can be drawn upon it with pencils made of brass, copper, silver, aluminum, or any of the softer metals. When used on the indicator it receives the faint line drawn by a brass point at one end of the pencil arm, and its special advantage over ordinary paper is that the metallic pencil slides over its surface with very little friction, and keeps its point much longer than a graphite pencil.
This paper can be used as a transfer paper for copying engravings or sketches, or anything printed or written in ink or drawn in pencil.
The best copies can be obtained by following the directions below: Lay the metallic transfer paper, face up, upon at least a dozen sheets of blank paper, and lay the print face down upon it. On the back of the print place a sheet of heavy paper, or thin cardboard, and run the rubbing tool over this protecting sheet. In this manner it is comparatively easy to prevent slipping, and prints 8 or 10 inches on a side may be copied satisfactorily.
Line drawings printed from relief plates, or pictures with sharp contrast of black and white, without any half-tones, give the best copies. Very few half-tones can be transferred satisfactorily; almost all give streaked, indistinct copies, and many of the results are worthless.