[pure-silver] Re: Data - RE: Re: Anybody use Rollie ATP and process with their recommended developer?
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Mon, 14 Jun 2010 18:42:56 -0700
----- Original Message -----
From: "Eric Neilsen" <ej@xxxxxxxxxxxxxxxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Monday, June 14, 2010 2:06 PM
Subject: [pure-silver] Data - RE: Re: Anybody use Rollie ATP
and process with their recommended developer?
Well, The film was hanging in the film drying box when I
got in this
morning. It has a substantial bluish color in the B&F
area. Processed it at
68F for 7 min. It appears to be a little bit much for the
1:14 development.
I might need to trim that back to 5. The biggest issue was
the curl of the
film; Took it off the clips and it rolled right up the
long way.
Eric Neilsen
4101 Commerce Street, Suite 9
Dallas, TX 75226
214-827-8301
I wonder if there is no anti-curl back coating or if
the support has some strange sort of memory. Most of the
time curling of film or paper is due to the differential
shrinkage of the emulsion vs: support. Film has had a back
coating of gelatin as an anti-curl device for a century now.
It also often has the anti-halation dye in it. The dye is
changed to a colorless form by the sulfite in developer and
fixer but neither the gelatin or dye is removed.
One reason for excessive shrinkage of the emulsion is
lack of hardening in manufacture. Gelatin is much like a
sponge in that it swells and contracts with moisture content
and pH. The "hardness" of gelatin is not quite the same
thing is physical hardness but rather a measure of the
amount of swelling with temperature and moisture content.
Soft gelatin changes a lot. Many modern B&W films are
hardened in manufacture so that they will withstand
processing temperatures of 100F, similar to color films,
however, many older emulsions are not and I suspect film
made by some of the smaller companies have pretty soft
emulsions. I am not quite sure what to do about this but
changing the nature of the fixing bath may help, that is, if
you currently use a non-hardening bath switch to one with a
hardener, or use one without hardener if you do use one.
Another possibility is to adjust the pH after fixing. If you
don't use a sulfite wash aid try one. Even if you are using
an alkaline fixing bath a buffered sulfite wash aid like
Kodak Hypo Clearing Agent will adjust the pH to neutral and
might make a difference.
--
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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