[alt-photo] Re: Are we still a list?
Richard Knoppow
dickburk at ix.netcom.com
Thu Jul 21 19:52:05 GMT 2011
----- Original Message -----
From: "francis schanberger" <frangst at gmail.com>
To: "The alternative photographic processes mailing list"
<alt-photo-process-list at lists.altphotolist.org>
Sent: Thursday, July 21, 2011 9:43 AM
Subject: [alt-photo] Re: Are we still a list?
> If one did want to exaggerate silver clumping or
> reticulation, how would one
> go about it? Nominal temperature developer to hot stop
> bath (acidic) or a
> hot water stop set up?
>
> I came across a beautifully reticulated 35mm negative (on
> HP5 +) a student
> had left in the darkroom at school and I want to re-create
> the effect.
>
> -francis
One way is to soak the negatives in relatively hot
water, say 90F for a time and then put them in very cold
water. The sudden shrinking of the emulsion may cause it to
reticulate from the stresses. If the emulsion is too soft it
may come off completely if the water is hot enough. It takes
some experimentation.
The old hot weather formulas used copious amounts of
sodium or potassium sulfate (not sulfite) in developers and
fixing baths because it has relatively little effect on the
developer although it slows it down a bit, but the high salt
content tends to reduced swelling. There was also wide use
of chrome-alum as a hardener in stop baths and in fixing
baths. Chrome-alum (potassium chromium sulfate) is a much
more effective hardener than white alum (potassium aluminum
sulfate) but must be in a highly acid solution to work. It
will work as a combination stop and hardening bath all by
itself. There are a number of formulas for chrome-alum
fixing baths. The problem with it is that the life is
limited and when it begins to age it leaves a green stain.
It was used exclusively for film because of the propensity
to stain. The super-hardening helps to prevent damage in
both fixing bath and washing.
If anyone is interested I will post formulas.
--
Richard Knoppow
Los Angeles, CA, USA
dickburk at ix.netcom.com
More information about the Alt-photo-process-list
mailing list