[rollei_list] Re: Idle Musings on Darkroom Chemistry, B&W
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Mon, 23 Jul 2007 23:19:49 -0700
----- Original Message -----
From: "Marc James Small" <marcsmall@xxxxxxxxxxx>
To: "Leica Users Group" <lug@xxxxxxxxxxxxxxx>;
<rollei_list@xxxxxxxxxxxxx>
Sent: Monday, July 23, 2007 9:52 PM
Subject: [rollei_list] Idle Musings on Darkroom Chemistry,
B&W
I pretty much agree about books. There are some others I
would add but they are getting old and hard to find.
As far as developers go I am rather skeptical of
non-orthodox formulas although some work. Anchell has a
formula which is supposed to be Diafine in _The Darkroom
Cookbook_. The first bath has Hydroquinone and Phenidone in
it. Hydroquinone alone is not an effective developer except
at very high pH. Generally it is found alone in very high
contrast developers which are alkalized with hydroxide
although it can also be found in some very warm tone paper
developers.
Anchell's formula for Diafine is:
Solution A
Water (at 125F or 52C) 750.0 ml
Sodium Sulfite, anhydrous 35.0 grams
Hydroquinone 6.0 grams
Phenidone 0.2 grams
Sodium Bisulfite 6.0 grams
Water to make 1.0 liter
Solution B
Water (at 125F or 52C) 750.0 ml
Sodium Sulfite, anhydrous 65.0 grams
Borax 20.0 grams
Water to make 1.0 liter
Soak film in solution A for three minutes, then transfer
without rinsing to Solution B for 3 minutes.
For some reason Anchell recommends using a water rinse
of one minute rather than an acid stop bath, and also fixing
in an alkaline fixing bath. I have no idea why because a
normal acid stop and fixer should not interfere with the
image and will prevent problems with staining and and
dichroic fog.
The claim is that this developer will deliver about 1
stop greater speed than a standard developer like D-76. This
may be since some Phenidone developers, for instance Xtol or
Microphen will increase speed by about 3/4 stop with the
same contrast.
I strongly advise agitation in both baths, the fact that
this is a two bath formula does not eliminate the need for
agitation to obtain uniform results.
Xtol: I have experienced the short time failure of Xtol
and have been reluctant to try it again. There is no doubt
in my mind that its about the optimum developer for many
films. A formula for Xtol appears in the patents issued for
it. The packaged formula may not be exactly the same.
I have seen considerable speculation, some from quite
expert chemists, as to why the shor time sudden failure
happens but none are definitive.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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