My understanding was that it depends -> since he also suggest using very weak HCl (or nitric acid) - something like 1% and such - in cyanotype processing. (Or maybe it was in some other context, but I'm sure that he actually suggests that...)
Of course, for pt/pd the suggested (in the literature) strengths of mineral acid clearing baths are usually something like 5%, considerably stronger than 1%...
Since citric acid works so well for me, I never had to consider HCl as a clearing bath. But I use HCl at that strenght (5%) often for acidification of Fabriano Artistico; a heavily buffered paper - if you accept that justification...
Originally Posted by donbga
Last edited by Loris Medici; 12-24-2009 at 03:12 PM. Click to view previous post history.
Reason: Typo correction...