Re: Gum problem(s)

From: Katharine Thayer ^lt;[email protected]>
Date: 11/18/05-10:43:54 PM Z
Message-id: <>

On Nov 18, 2005, at 2:20 PM, Christina Z. Anderson wrote:

> Second, I don't think I'd take the humidity thing too far. I have
> gone from South Carolina to Montana, from 50-70% humidity to now 25%
> humidity, and my gum exposures are the same. The length of time I can
> successfully keep a coated and unexposed gum print before it succumbs
> to dark reaction is probably changed, though.

hmm. Maybe it doesn't make so much difference at a lower dichromate
concentration, or something; at any rate I do have to adjust my
exposures for changes in humidity-- like when there's a dry spell after
a long rainy season, I have to expose longer. Not 20 minutes,
certainly, but another minute or two. But even when it's dry, the RH
here is seldom below 50-60%.

I don't know how else to account for the fact that my exposure times
are so short with the photoflood, than the humidity of my environment,
along with the established link between humidity and exposure required
for hardening. How else would you explain it, unless the idea of long
exposure times with photoflood is simply a myth and not based on actual

But this may just be one of those things we'll have to agree to
disagree about.
Received on Fri Nov 18 22:44:49 2005

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