Archived posting to the Leica Users Group, 2009/04/22
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]So why Sodium Sulfite at 100 g/l and Oxyethyl-ortho-aminophenol? I would think you could cut back to 40-50 grams/l which would increase actuance I think. Unless the Sulfite also is needed as an accelerator for the Oxyethyl-ortho-aminophenol, which is likely. The reduced sulfite would also increase actuance by allowing the pyro to proportionally stain the density. The Sodium Metaphosphate is likely used to increase the rate of hydroquinone developement and give maximum contrast. The potassium bromide here would then be a restrainer, which seems unnecessary as the sodium metaphosphate isn't that caustic? Not as much as Sodium Hydroxide at least. If fog is a problem then perhaps a less caustic sodium would work. Interesting formula to play around with. I'll have to see if I can get some of the aminophenol, and Sodium Metaphosphate, both not the usual fare. At 11:31 PM 4/21/2009, you wrote: >ATM49 is very similar, probably the same as AGFA Atomal, which I've tried. > Calbe A49 is also likely close. I have no idea what you can and cannot > buy >off the shelf anymore, since I only really buy Xtol and mix everything else >up myself. Don't confuse Atomal with Atomal FF; they are totally different >developers - the latter is a phenidone HQ developer. >The formula for Agfa Atomal is: > >Package A: >Oxyethyl-ortho-aminophenol 6g >Pyrocatechin 10g >Hydroquinone 4g > >Package B: >Sodiumsulfite anhyd. 100g >Sodiumcarbonate anhyd. 25g >Potassium bromide 1g >Sodium metaphosphate 1g > >Dissolve in 750 ml of water at 50? C. Add cold Water to make 1 litre. > >It seems unnecessarily complicated to me. > >The o- aminophenol correctly is a silver solvent, not an active developer. > One of the Windisch formulae uses 0-phenylenediamine in a similar way in >an extra-fine-grain developer where Metol is the main developing agent. > o-phenylenediamine is not an active reducing agent but is an effective >solvent of silver halide. > >In my experience all the Agfa formulae lower midtones more than I want most >of the time. I was thinking that I would develop some photos that I will >take in Prague later this year in Rodinal or Rodinal Special to take >advantage of the dark look, but having seen this maybe I'll try Atomal. I >think mostly I prefer Xtol for providing the finest grain with excellent >acutance. > >You can also get a VERY similar look at much lower cost by adding 3 mL of >Rodinal per litre of Xtol 1+4 or 1+5. If you get fog or signs of infectious >development due to lowering of the pH and activation of the ascorbate in the >Xtol alone by the hydroxide in the Rodinal, add 1-2.5 g/L of borax. This >brings the pH back down while maintaining alkalinity and activity. > >Irrespective of the developer, the photos look great. Keep at it, > >Marty > >_______________________________________________ >Leica Users Group. >See http://leica-users.org/mailman/listinfo/lug for more information Chris Saganich MS, CPH Senior Physicist, Office of Health Physics Weill Medical College of Cornell University New York Presbyterian Hospital chs2018 at med.cornell.edu http://intranet.med.cornell.edu/research/health_phys/ Ph. 212.746.6964 Fax. 212.746.4800 Office A-0049