Concise instructions in the art of retouching (1876)
Ourdan, J. P, author, Burrows and Colton, London · London : Marion & Co. · leaf 21
7 THE LIGHT. THE MAGNIFIER. ground glass at half the angle formed by the mirror and middle frame of the desk when opened, thus : — … A piece of ordinary glass coated with matt varnish will answer the purpose as well as, if not better than, ground glass ; besides, it is not as expensive, and if broken can be replaced at a very trifling cost. The Magnifier. The magnifying-glass used should be of about six inches focal length and,…
Photography
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
