Re: ferri sesquichlorati
(excuse not changing the subject line--i know i know)
Dry mount press works good for this lumpiness, if you have one.
I find that another problem is that the succeeding layers more easily fish eye on me, so I have to use a bit thicker gum, in fact, or just be really cautious to brush well and keep brushing to eliminate those darn spots. Then, the problem can be the thicker layer flakes more easily. This week I had the fish eye problem on my last coat, so I actually had to WIPE off the coating of magenta, mix a new batch of pigment up with thicker gum, and brush it on. I can't believe it, it worked fine. I thought the print was a goner, at least would stain or SOMETHING. This on glut sized paper, tho.
Speaking of glut, I sized a huge batch of paper the other day, laid all over my kitchen (make hay while the sun shines--all family members were gone). I even took a picture of it to make myself feel good. Anyway, I decided this time (silly me) to try Ryuji's stronger concentration of glut that he uses in his silver emulsion mix (why do I always test new things), which amounts to 30 ml per liter gelatin, and I had dripped some on my table without knowing it. I had to scrape it off, it was stuck and hard for good. And, by the time I got to the last sheets of paper (40 sheets) I wasn't paying attention and there were at least 5 that pooled hardened gelatin that doesn't budge, in the center. The rest of the paper works fine, but 30ml for a liter is definitely sufficient to harden anything!
The problem that often arises when one attempts more than 8 layers is a "warping" effect caused by more gum sitting in the shadows than in the highlights. As the shadows areas build in density with each coat, surrounding highlight areas continue to clear. The shadow areas begin to appear on the dried print as shiny, lumpy islands of gum that warp the surface of the paper. Keith