Re: Gum Printing/Observations

Tom Ferguson (tomf2468@pipeline.com)
Mon, 22 Jun 1998 09:01:27 -0800

>> katharine thayer wrote:
>> I use premixed gum that I bought from...Photographer's Formulary, I
>> think. Or Daniel Smith.
>
>Judy Seigel wrote:
>Last year I participated in a bi-coastal gum test. A friend sent me some
>of his Photographer's Formulary gum, we both made tests, often on the
>same papers. I'd have to check the file to see how the BFK worked, but
>that gum here was worse-to-impossible on 11 out of 13 papers -- with the
>other ingredients I was using.
>
>Even with ingredients more or less matched, it was worse. We speculate
>that it's the water.<SNIP>

I was the West Coast end of these tests. It's scary to remember back to
our "it must be the water" conversation. I'm moving to a different water
system (Ventura County, California) in 9 days! OH OH!!!

I had good luck with the Photographers Formulary gum, but eventually
changed to the Daniel Smith. I use the cheaper of the two gums available
under that brand name, it looks like used motor oil, but works great???

I also had good luck with BFK (and Tri-Ess "hard" gelatin and glyoxal), but
eventually settled on Lana paper (clear a little bit more and I liked the
surface texture).

>The friend changed his paint brand, which had been Grumbacher Academy
>(student grade)<SNIP>

I wondered when I read the original post if Katharine started in gum (as I
did) with a Photographers Formulary "kit". Not a terrible way to start,
but the paints they give you shouldn't become a standard. There are far
better brands/series out there.

>> I was intrigued by your (I think that was you) mention of black gouache
>> in the 1996 archives, and may try that sometime, if you're still
>> advocating that. Isn't it pretty opaque?<SNIP>
>
>Ah, my late lamented Rowney jet black gouache. I came to the end of the
>tube and replaced it with nominally the same, but of 2 years later
>manufacture. Couldn't get it to clear<SNIP>
>
>As for opaque, this was for one-coat gum, where you want opaque<SNIP>

This was one of the first confusions in Judy and my tests, she had an old
tube, I had a new tube. The current Rowney jet black gouache will not
work. Try the Windsor Newton. I also use gouache (in many colors) as a
first (shadow) coat on a lot of prints. Then I use transparent colors over
this. It gives more contrast (snap) to the print. A trick I think I
learned from Judy.

So, from a "far from expert" gum printer who has done a few tests. The
biggest variables are (in order of importance):

1) Coating technique, learn that less is better. Use as little solution as
possible.

2) Paper, settle on one or two papers and learn them. Changing paper will
change everything else.

3) Sizing and hardening. I can only assume that this is another water
issue. Judy and I got entirely different results. She got good results
with Knox food gelatin and poor results with hard gelatins, I got exactly
the opposite??? And yes, I did repeat that test??? But I think everyone
who uses gum and gelatin has gotten better results hardening with glyoxal
than with the old standard formalin.

4) Paint, not just a brand, but individual colors vary greatly in usability.

tomf2468@pipeline.com (Tom Ferguson)