no halftones on glass, stain test, really usable varnish recipe
Some inane information you always wanted to know (NOT).
Finally found the first mention of the fact that gum printed on glass will produce only a silhouette--no halftones. Koesters' 1904 book. He had this whole theory about halftones being produced by the adherence of the gum layer to the paper bumps and crevices and such and the glass not working fit nicely into his theory.
Paul Anderson in Sept. 1913 American Photography was quoting Dr. Wilhelm Koesters' book and says he confirms it in practice. In this same article he expounds upon the stain test, both which were in Dr. Koesters' 1904 book. Anderson repeats the glass saga in 1917, 1935, and 1939. It gets repeated again in at least one book from our time with a cursory glance through my notes.
Apparently Koesters' book was fairly respected because he "standardized" gum. His stain test was quoted in 1906 and 1908 in the BJP, too.
Crystal varnish recipe from the Photo Beacon for Judy to make her "vernis soehnee" millions; get that huge kettle out:
gum sandarac 10 lb, Canada balsam 2 lb, copal varnish 20 oz, oil of lavender 8 oz and alocohol methylated spirit 8 gal.
Research research research, relieved a bit from a wonderful visit with Thom Mitchell who was in town today. So nice to connect visually with other alt listers! We gabbed photo for 3 hours!!
Christina Z. Anderson
Assistant Professor, Photo Option Coordinator
Montana State University, VCB 220
Bozeman Montana 59718