I've been browsing a lot of photographer's web sites lately.

There are a lot of photographers selling gelatin silver prints which they claim are 'processed to museum archival standards", or similar wording. The sentences with these statements are all eerily similar, as if long ago, someone made such a statement in the ur-website of the original photographer, and ever since it's been copied from website to website.

So, what standards are they referring to? Can anyone provide a link to such a set of standards? What are the standards like, and what do they standardize?