Re: Taming Fabriano Artistico (Trad. White) for Cyanotype
From: "Christina Z. Anderson" <zphoto@montana.net> Subject: Re: Taming Fabriano Artistico (Trad. White) for Cyanotype Date: Tue, 02 Dec 2008 07:09:58 -0700 > Also, I noticed an interesting difference when sizing it > with formalin vs. glut. I do not know the acidity of either > but when I use formalin size, my guess is it is more acid > because the cyano layer is much more normal and dark on top, > whereas with glut the cyano layer is paler. So your size of > choice will have some effect. But I do size with glut. My glut stock is weakly acidified with acetic acid to pH of about 4. Glutaraldehyde hardens gelatin even at this pH, but generally the hardening reaction gets faster near pH of 8, and this is also true for formaldehyde. I don't know about your stock of formaldehyde, but commercial stock is also weakly acidified and also contains a small amount of methanol as the stabilizer. I don't think methanol has a significant role in the effect you are talking about. While I do not know whether commercial formalin stock has more acid in it than my dilute glut stock, it is plausible for the formaldehyde hardened gelatin size solution to contain more acid because formaldehyde is usually used in significantly larger quantity than the amount of glut you and I use. -- Ryuji Suzuki "Yesterday's just a memory, tomorrow is never what it's supposed to be." (Bob Dylan, Don't Fall Apart on me Tonight, 1983)
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