Starting on page 160 of his book Post Exposure


Ctein described a test begun during June 1995, wherein he divided three RC prints into quadrants, then treated them so that one quarter was washed only, the second quarter was very lightly selenium toned, the third quarter was treated with (then-current) Agfa Sistan and the fourth quarter received both selenium and Sistan. He then sealed them in frames and hung them where they received "ample" daylight (but no direct sunlight) and, at night, incandescent light. When the book's first edition was published in 1997, he reported all three untreated print quadrants had silvered out within a year, but the treated quadrants showed no change. At the second edition's release in 2000, he updated those results, saying "still no change." Note that the on-line PDF carries a 2011 copyright, but it's identical to the 2000 second edition.

Since being sealed in a frame and exposed to light has long been thought likely the worst environment for RC prints, I was curious whether Ctein's test is ongoing more than 20 years after June 1995. Today I asked him that very question. His answer: Yes, the prints have been kept in the same environment the entire time since 1995. He said the quadrants treated with very light selenium toning and/or Sistan continue to look fine -- no silvering out or bronzing. He closed with "So, I guess it works."

While the prints Ctein tested were made on Kodak Polycontrast and Agfa Multicontrast Premium papers, I think it's reasonable to extrapolate that today's RC papers ought to fare as well or better, especially since Agfa itself subsequently changed its paper formulation based on research prompted by Ctein's test. In light of our drought conditions, I'm planning to use a lot more Multicontrast Warmtone RC with greater confidence after hearing from Ctein today.