Re: Gum -- Drying temperature

I typically work on several prints during a gum printing session. I live in
a very dry climate and do not normally use heat to dry the paper. I start
making exposures as soon as the emulsion is dry.

Sometimes, before making additional exposures on a print, I use a hair dryer
with gentle heat to shrink the paper slightly to achieve perfect
re-registration with the negative. I'll sometimes dampen the backside of a
print slightly to expand it, again to match the negative. I have not seen
any damaging or negative effects from using this slight amount of dampness
or heat.

It's great to hear that you made a good print during your latest session.
If you're not already doing so, I suggest keeping detailed notes so that you
can repeat your successes and troubleshoot the failures.

I certainly don't think you're "hogging the list" by asking questions. This
list is a tremendous resource, please continue to use it.

Best regards,
Dave Rose
Big Wonderful Wyoming

----- Original Message -----
From: "Gary Nored" <gnored@centurytel.net>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Wednesday, November 05, 2003 4:50 PM
Subject: Gum -- Drying temperature

> I was trying out suggestions from this list today. I increased the
> dichromate:gum/pigment ratio to 1:1 and then hung the paper in
> my new drying closet (dehumidifier in a broom closet), and forgot
> about it for an hour or maybe two. The broom closet got very warm
> and the paper was bone dry when I got to it. But it would hardly
> produce an image at all, at any exposure!
>
> Sooo, went back, and made another sheet at the same ratio, but
> with slightly more pigment. Again, not thinking clearly enough to
> realize that I was adding another variable here, I put the sheet in
> the closet to dry. This time, I turned the machine down (so the
> room was cooler) and I took the paper out faster.
>
> VIOLA! Best print I ever got. Amazingly sharp, not grainy at all,
> wider dynamic range than I've ever seen. A little staining, but the
> paper was somewhat sloppily sized, which I've discovered is a no-
> no.
>
> So now I wonder--how important are the DRYING conditions to gum
> bichromate printing? How important is temperature? Time-to-dry?
> Time between drying and exposure?
>
> Sorry if I'm hogging the list. I check the archives before asking
> these questions, but the search function is so rudimentary that I
> often give out after reading the first 10 or 20 thousand messages :-)
>
>
> Regards,
> Gary Nored
> http://home.centurytel.net/Gary_Nored/
>
Received on Thu Nov 6 08:24:22 2003