>There was a lot written from early 1900s to as late as 1950 on paper
>negatives in the magazines, even in books. Ansel Adams & Co
>thought they'd stamped out the practice in the '50s & '60s, but after
>lying dormant in spores under the ocean it reappeared, circa 1970 and
>continues to spread.
An excellent book on the subject is _Picture Making with Paper Negatives_
by Nowell Ward, American Photographic Publishing Co., Boston 1943. It's
written as if he is actually doing the procedures while writing the book.
PHOTOGRAPHERS PLACE may have a few copies laying around.