Etching of inscriptions and drawings on metals

Etching of inscriptions and drawings on metals – Places, which are to remain convex should be covered with a protective varnish, preferably asphalt, and etch the surface in any of the solutions specified in the metal etching regulations. A sometimes recommended method of covering the entire surface with varnish, with wax or paraffin and then scratching the spots, to be etched, does not give good results, because it is not possible to thoroughly clean the surface in these places, and any remnants of the protective coating will cause uneven etching.
Photochemical method. It is quite difficult to make, however, it is unrivaled in accidents, when it comes to sharpness and precision of drawing. It consists in covering the metal surface with a photosensitive emulsion, which becomes insoluble after exposure, but easy to remove from places, which have not been exposed. The next step is to etch the exposed areas.
Wytrawioną na matowo powierzchnię metalu powleka się jedną z emulsji.