[rollei_list] Re: Idle Musings on Darkroom Chemistry, B&W
----- 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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