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.
Because exposure times are longish, it may be best used for gelatine
silver or gum prints (gum being the fastest "non-silver"). A student of
mine last year did most of her gums from RC print negatives (made by
contacting print to print, needless to say). Exposures were 15 to 20
minutes. The question was, what do they look like ? -- depends on the
negative. No tell-tale residue f that's what the question meant.
The advantage of RC over fibrebase is less texture and it lies flat,
rather than tending to curl. But single or doubleweight paper is OK
too. If your gum, for instance, is on paper with any texture at all, the
paper negative texture won't be noticeable.
Judy