Ctein wrote some stuff in Photo Techniques about silvering out of RC papers, not yellowing, but the big factor was that the prints were under glass. That was a few years ago. You might try and find the back issues. Apparently sealing the "paper" in with it's own gasses is a bad thing. I think he also said prints that were framed right after being made did worse than those allowed to age a bit.(posted 8348 days ago)