Quote Originally Posted by ROL View Post
I second the etching technique as the best archival of a lot of bad alternatives. However, the unavoidable resulting emulsion breaks, though not much better by bleaching, visible at angles on glossy papers absolutely gives me the shivers on an otherwise "perfect" print. So much so that I have thrown out entire runs of otherwise fine prints to reprint them if the problem was not on the negative itself (i.e., during enlarging). One of a kind, hand made prints ...ahem .
This is why you use a gummed envelope (not the self sealing type) and after knifing the hair repair the surface by dissolving a small amount of the gum in a drop of water and applying with a fine brush. As with all retouching working too hard to remove an imperfection can make it worse a light touch is needed.

Steaming the surface of a print will also lessen the effects of a retouching knife.