D23 a due bagni

05 marzo 2007  Pier-Luigi  Fotografia (0)
Joseph Lipka on Divided D-23 I have noticed some talk about D-23 developer recently, and it appears that there are almost as many variations of this developer as there are photographers.  I have been using D-23 as a two bath developer for about ten years. The formula and some other text is included as part of the overall instructions for processing Palladio Platinum Paper made by the Palladio Company in Cambridge, MA. My primary use of D-23 is film negatives for platinum printing. I have been using TMAX 400 in 5 x 7 or 4 x 5 sheets.  Exposure index for both films has been 400.  Here is the recipe:   Solution A 750 ml distilled water at 120 F, add 7.5 grams elon (metol) and dissolve completely. Then add 100 grams sodium sulfite and dissolve. Fill with cool water to make 1000 ml. Solution B Dissolve ten grams Kodalk in 1000 ml distilled water at 120 F. This basic 1-liter set of chemicals will develop 600 to 800 square inches of film. 20 5 x 7 sheets. This makes it a "one shot" developer for me. Times and Temperatures The instructions from Palladio advise times between 9 and 14 minutes at 72 F for Solution A and 3 minutes in Solution B.  Time less than 3 minutes for Solution B is not recommended. My Process My developing process is to pre-soak the negatives for a few minutes, until the sheets move freely in the water. Then I develop in Solution A for 10 minutes. I shuffle sheet film continuously through development. Then in to Solution B for 3 minutes, also continuously shuffled. I try to start both baths at 70 F when I start development, but body heat transferred to the developer usually raises the temperature about 3 or 4 degrees by the time I am finished. After developing, I use a regular acetic acid stop bath, then a hardening fixer. Orbit bath, wash and photo flo complete the process. I asked Rob Steinberg from the Palladio Company about alternative developing times.  He gave me the following information, attributed to Tillman Crane. Exposure Development Time in A Time in B + 1 stop N-2 6 minutes 3 minutes As metered N-1 8 minutes 3 minutes As metered N 10 minutes 3 minutes As metered N+1 12 minutes 3 minutes Divided D-23 by Ed Buffaloe Recently someone on the Large Format Forum was trying to find an article (by Jim Veenstra) from an early issue of View Camera magazine on the Divided D-23 developer. I happened to have the article, so I shared the formula and developing information with him.  While I was at it I read the article again myself.  It piqued my latent interest in divided developers, so I read up on them a bit more and did some minor experimentation. This brief article is designed to provide the basic formulas, point out the obvious relationships between them, and provide links to various resources for further information both on and off the web. My first thought when seeing the Divided D-23 formula was that its not really a divided formula at all (its D-23 with an alkaline after-bath). This led me to compare D-23 with D-25 and D-76, and the relationships were immediately apparent. Ingredients Standard Developers Divided Developers Solution A D-23 D-25 D-76 DD-23 DD-76 Water (125°F/52°C) 750 ml 750 ml 750 ml 750 ml 750 ml Metol 7.5 g 7.5 g 2 g 7.5 g 2 g Sodium Sulfite 100 g 100 g 100 g 100 g 100 g Sodium Bisulfite - 15 g - - - Hydroquinone - - 5 g - 5 g Borax - - 2 g - - Water to make 1 liter 1 liter 1 liter 1 liter 1 liter Solution B           Borax - - - 2 g 2 g Water to make - - - 1 liter 1 liter   D-23 has 7.5 grams of metol and 100 grams of sodium sulfite. Thats it. D-25 simply adds 15 grams of sodium bisulfite.  D-76 reduces the metol to 2 grams, then adds 5 grams of hydroquinone and 2 grams of borax. Solution B for the divided developers is simply 2 grams of borax in a liter of water. There is a variant of the Divided D-23 formula by H. Stoeckler, in which he reduces the metol to 5 grams in solution A and increases the borax to 10 grams in solution B.  Anchells The Darkroom Cookbook gives another variation of the Stoeckler formula, in which solution A has the sulfite reduced to 80 grams and 20 grams of sodium bisulfite is added; he also gives a Divided D-23 Variant wherein the metol is reduced to 5 grams (a la Stoeckler) and the borax in the second bath is increased to 18 grams. Joseph Lipka uses a variant that substitutes sodium metaborate (Kodalk) for the borax in solution B. Solution A DD-23 Anchell DD-23 Stoeckler Stoeck. Var. Water (125°F/52°C) 750 ml 750 ml 750 ml 750 ml Metol 7.5 g 5 g 5 g 5 g Sodium Sulfite 100 g 100 g 100 g 80 g Sodium Bisulfite - - - 20 g Water to make 1 liter 1 liter 1 liter 1 liter Solution B         Borax 2 g 18 g 10 g 10 g Water to make 1 liter 1 liter 1 liter 1 liter Supposedly a divided developer has the developing agent in solution A and the accelerator in solution B. But obviously any solution A with 100 grams of sulfite in it has enough alkalinity that it can function as a developer without the addition of further accelerator.  So when films are in the above solution As, they arent just absorbing developing agent and waiting for solution B to provide enough alkalinity to begin development--they are developing the film. But solution B is where the compensation comes in. In solution B the developing agent quickly exhausts itself in the high values where the greatest density lies, while the low values continue to develop.  So, essentially, you develop in solution A until your high values are almost where you want them, then you place the film in solution B and develop until the shadow values are where you want them. If you are not experienced at development by inspection, you may have to do a little experimenting to get the times just right. Pre-soaking in water is not necessary. Use your normal agitation method in solution A, and unless you want a very strong N-2 contraction, go ahead and give 10-15 seconds of agitation per minute (or more) in solution B as well.  (For N-2, dont agitate solution B at all.) Increasing the time in solution A raises overall density and contrast, whereas increasing the time in solution B will only raise shadow detail if the film is returned briefly to solution A first.  Jim Veenstra gives some suggested developing times in his article, and since the article is so hard to come by I am going to reproduce his suggestions here. You will note he considers that D-23 does not require the second bath with T-Max films except for an N-2 contraction.  68°F N-2 N-1 N N+1 N+2 Max Film EI A B A B A B A B A B A B Tri-X 200 4m 3m 4.66m 3m 5m 4m 7m 4m 9.5m 4m 15m 4m TM 100 100 5m 4m 6m   7m   9m   13m   20m   TM 400 400 4m 3m 5m   6m   7.5m   11m   16m   Just to test the above times, I developed two 4x5 pinhole negatives in the standard Divided D-23 formula.  The film was T-Max 400, rated at 320, developed for 7 minutes in solution A and 2 minutes in solution B at 68°F.  The results compared quite favorably to my PMK negatives of the same subjects.  I plan to use this developer in the future for N-1 and N-2 contractions.

 

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