The practical printer : a complete manual of photographic printing (1874)
Hearn, Charles W · Philadelphia : Benerman & Wilson · leaf 184
the centre, lay your porcelain plate in the position you want it, then throw the wire loops toward each other. This will make room for the plate between the bed and the negative. If it does not fill up the space, the four set-screws at the back of the frame will make it vary just to fit ; then… … The “Jacoby Frames ” are excellent in all of their parts, being so made as to secure perfect contact between the negative and porce¬ lain, however uneven they both may be.
Photography -- Printing processes · Photographs on porcelain
Internet Archive · Smithsonian Libraries · Public domain (published before 1931). Free to use for anything.
