Quote Originally Posted by Photo Engineer View Post
Current images from color RC papers are expected to last from 100 to 200 years depending on the keeping conditions and manufacturer.
This depends not only on the material used, but also the test condition and interpretation of the data. It also strongly depends on the acceptable color shift or density loss used to determine the life of the image. There is no single valid set of criterion and test method, so that the published test results vary a lot even for the same material, such as Kodak Endura. Depending on the test conditon and interpretation, this same material is rated 20 years (stronger light, no UV filter, etc., used by Wilhelm) and a couple off hundred years (weak light, UV filter, etc., used by Kodak). Images on current Endura may last for 200 years in ideal refrigerated museum storage with molecular sieve, but in the storage condition of average consumers, I doubt that the image will go significantly faster.

However, I also believe that modern RC paper base is a lot more permanent than earlier ones. I also agree that antioxidants added to the polyethylene resin are not usable in baryta sizing layer. Those antioxidants have to be nondiffusible but there is no good way to make hydrophilic nondiffusible antioxidants to add to baryta sizing, but it's easy to make nondiffusing hydrophobic antioxidants for polyethylene.

Another consideration is that I have a final rinse solution that adds UV blocker and antioxidants to the print. (Similar idea to sunscreen protection but with extra antioxidants.) I'm not sure why Kodak or Fuji never came up with this kind of solution (perhaps cost consideration, as the ingredients are not very cheap), but this treatment is very effective with untoned silver images on RC base in my testing with UV and oxidizing agents.