Thanks. There's a link to the patent in Ed's article.
So what are you up to; .5 gram hydroquinone and 1.5 gram borax?
Originally Posted by David A. Goldfarb
And what do you think is the reason for the high temperature
development? Ordinarily one would think it due to a lack of
sufficient activity at more usuall temperatures. Dan
Currently 0.5 g hydroquinone and 1.0 g borax. I think if I add more borax the base fog problem is going to increase.
The high temperature is odd, but with development times of around 20 min., I'm sticking at 86 deg. I'm guessing that it has to do with the compensating effect of the developer. If it were more active, the highlights would develop more quickly, and it wouldn't be able to do what it claims to do in the patent.
Okay, I think I'm ready to call it "soup."
I've posted a lousy scan of a nice neg in the Technical Gallery--Arista.EDU 400 5x7", EI 1280, K2 filter, XR-1 (B) (1+1) with double the borax, double the hydroquinone, and 2 ml/l (stock) of benzotriazole 1%, 20 min. rotary processing in a print drum (preceded by a 2 min presoak). I decided to try drum processing just to eliminate the possibility of fog from light leaks in the darkroom, which I think was part of my fog problem processing at this EI in an open tray for 20 min.
The neg has low fog with detail everywhere and should print nicely on Azo somewhere between grades 2 and 3. Grain is better than I expected, and sharpness is quite good. The snow has detail on the neg, which didn't make it into the scan, and the scanner is responsible for some streaking in the sky area. The drum agitation is more vigorous than my tray agitation, so I can probably back the time off to 18 min.
Once I've tested it a bit more, I'll post it to the chemical recipes area.
"If it were more active, ... " But that's my point, it is
Originally Posted by David A. Goldfarb
active because of the high temperature. Why not make
active at a lower temperature by making more alkaline?
I don't know. I've all the ingredients and within a few weeks
may be working with it. I think that high temperature one
reason it is not now on the market.
IIRC, the patent allows for a lot of variation; patented 4/78.
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It's a good question.
I tried making it more active by using stock solution instead of 1+1 dilution, and that produced unacceptable fog levels. Looking back at the patent I think Anneman's idea was to balance the amount of borax with the phenidone, and there is probably a point of diminishing returns where there is no advantage to making it more alkaline because the quantity of developing agent is so small (or perhaps there is some other consequence, like pinholes with an acid stop). The high temperature I'm guessing is to keep processing times under 25 minutes.
Let me know if you try it and get interesting results.
Let me remind you that if you have a negative that shows the shadow detail you want but is low in contrast, you can bleach in a ferricyanide-bromide solution and redevelop in PMK, Pyrocat HD or even a simple hydroquinone-carbonate solution to produce a stained and tanned negative which contains the original silver plus the stained image. This is especially effective when you are printing on blue sensitive graded paper. If one application doesn't do it, it may be repeated, BUT the tanning contracts parts of the gelatin and repeated tanning will sometimes cause strain cracks in the emulsion.
The same bleach you would use as the first stage of sulfide sepia toning is fine. Bleaching goes to completion. The redeveloper should have little or no sulfite. Since the development also goes to completion, there is little requirement for exact measurement of ingredients. I have used 1 teaspoon each of hydroquinone and carbonate in a pint or 500 ml of water. Needless to say, it doesn't keep. You could make enough of separate hydroquinone and carbonate solutions for a session and mix them in equal proportions just before use.
Catechol may be used in similar fashion, and so may pyrogallol. The stain colors will differ. Of course, if you have PMK or Pyrocat HD on hand, you may use either.
The whole process is carried out in room light because the film must be fully exposed in order to redevelop all the silver. If you are going to use a developing tank, be sure the bleached negative is thoroughly exposed. You should probably do one sheet in a tray to get an idea of how long it will take. Over development will do no harm.
That's true, though I wouldn't want to have to do it as a regular part of my process.
What's the advantage of bleaching and redeveloping over, say, selenium intensification, which is what I usually would do in that situation?
The grain stays the same. The stained image behaves differently with VC and blue sensitive printing materials, which is one of the advantages often quoted for PMK and other staining developers. If you use hydroquinone, it is no more dangerous than most of our print developers. I have not compared the results with selenium, but I don't remember that one can use selenium more than once. Anyway, I suggest a trial on something not important just to see what it can do by comparison with selenium. You probably have on hand everything you need.
Thanks. With selenium I can usually get a one-stop expansion, but I suppose that if I think I might need more then that, then I could bleach and redevelop, and then tone if I need more.