Someone pretty serious about archival processing mentioned to me that his last bath before drying prints (fiber, glossy) is a flattener. There are two I know of, Superflat and Photoflat, I think, one by Edwal and one by Kodak. This would be after selenium toning and final wash. I dry prints from plastic clothes pins back to back, and they are relatively flat, depending upon the humidity. I often have to press them in a dry mount press, set low, then left till cool. This is for matting and framing without dry mounting the prints.
The question: Someone on a photo.net thread said once that these flatteners are not considered archival, a real problem considering it is the last thing before drying. I called Edwal about their product, and the best I could get from tech support was that the inventor, in his original notes (goes back aways, as you might imagine) said there was no evidence that it was not archival, not too much of an endorsment.
Does anyone out there know about this?