Re: Homemade POP ??

From: Martin Angerman <paleophoto@adelphia.net>
Subject: Re: Homemade POP ??
Date: Tue, 21 Sep 2004 20:51:04 -0700

> 3. Has anyone tried using 0.1% azide in solutions as a
> preservative. It's kind of nasty, but it really keeps the stuff
> from growing blue-green fur.

Sodium azide is used as fungicide, herbicide, etc. but its toxicity is
not very preferable for this type of application, I think. I use
sodium salt of 2-phenylphenol, which has relatively low toxicity but
is a few times more effective as fungicide and bactericide compared to
phenol or thymol. Bayer sells this compound as Preventol ON extra
flakes, and it's also sold by Kremer-pigmente under the same name. No
smell or outgassing when dissolved in water. I use this
(2-phenylphenol) for my gelatin sizing solution and silver gelatin
emulsion.

In reference to earlier posts of this thread -

I don't make POP but prints made with homemade emulsion coated on
watercolor paper look more like Van Dyke prints with higher Dmax than
silver gelatin prints made with all commercial materials. Quite
frankly many of my negatives (subject matters) are good for making
sharp prints of wide density range using commercial papers, and they
don't look particularly good on my homemade papers. But some stuff I
shot anyway but never liked before, like those negatives I didn't
think worth the keeping space, occasionally print very nicely on
homemade papers.

Using silver gelatin emulsion, there is a large room for controlling
the print image by selection of paper, developer and toning
techniques. I haven't got into it yet but lith printing on homemade
emulsion is another big variable. The advantage of silver gelatin is
obvious: I can print by projection (enlarge), and I can use negatives
developed to print on grade 3 paper. I'm not sure why more people are
interested in POP than developing out emulsion, but I even if it's
gelatin POP, I wouldn't assume it would look similar to ordinary b&w
prints just because it uses gelatin. (unless you machine coat it on
well sized baryta paper support or something...)

--
Ryuji Suzuki
"You have to realize that junk is not the problem in and of itself.
Junk is the symptom, not the problem."
(Bob Dylan 1971; source: No Direction Home by Robert Shelton)