Re: Terminology - gum
Hi Halvor, I agree with you that it's confusing to have the two names, especially since it's not generally agreed what the two names mean. Like you, I take "gum printing" to mean a dichromated colloid process using gum arabic as the colloid. As Sandy says, there are people who use the term "gum printing" to mean a nontransferred direct colloid process no matter what colloid is used. But others use "direct carbon" for that umbrella term, and I personally find that less confusing than to use the more specific term "gum" as a general category. But using either of these terms as a general category leaves one in the dark as to what colloid is involved. I remember a very confusing correspondence I had several years ago with a fellow "gum printer" where some of the things he said about how the process works were inexplicable to me, and finally it came out that he was gum printing with gelatin as the colloid. And also, sometimes people who use gum arabic use "direct carbon" to designate their method, which confuses the issue further. As to your impression that gelatin gives a sharper image and is less forgiving with coating problems, I wouldn't necessarily say that. After I understood that my correspondent was using gelatin in a gumlike process, I of course had to try it for myself. No doubt if you used it at room temperature you'd get problems with brush marks as the gelatin would be setting up while you were brushing it, but knowing that gelatin sets at room temperature, I kept it heated while coating, and had no such problems. I found that rather than sharper than the gum image, my "gelatin" prints were softer. It's possible that gelatin is slower than gum and I needed to expose it longer to harden the gelatin sufficiently to hold the details; I didn't do a lot of experimenting with it, I was just curious. I made maybe four or five gelatin prints but didn't find it interesting enough to pursue further. Katharine On Dec 11, 2006, at 10:42 PM, Halvor Bjørngård wrote: Hi
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