Divided developer questions
I've been getting a bit curious about divided developers recently, and so gave one a try. At semi-random, I picked the General Purpose Divided Developer formula from Anchell's Darkroom Cookbook, 2nd Edition (formula #5 in that book). This has an MQ bath A and a bath B that consists of sodium sulfite and borax. I tried it out on a roll of 35mm Fomapan 400, but I got very thin negatives. On more (and more careful) reading, I found advice to use continuous agitation with divided developers, so I shot a roll of medium format Fomapan 400 and tried it again, but the results are, if anything, even thinner. I also noticed that bath B is producing a sludge-like gray precipitate that's coating the bottle. (Bath B is supposed to be good for several rolls.) So:
- Is the sludge-like precipitate normal, or is this a sign that I mixed it wrong or have some sort of contaminant? (I mixed only half a liter rather than a full liter, and it's conceivable I neglected to halve one or both of the ingredients in bath B.)
- Is it likely that this developer would work better with other films? I'm reluctant to use it again, but I'll do so with another type of film if this developer is known to produce poor results with Fomapan 400.
- Any other suggestions for divided developers to try? Aside from curiosity, my main interest is in finding something with consistent development times across films, which can be handy on those occasions when I've got a roll of an unfamiliar film and can't or don't want to do a test roll to find the optimum development time.
Divided developers work differently with different films. They are based on the thickness of gelatin and the quantity of silver coated. As this varies, time in the two baths must be varied to optimize the process.
Continuous agitation in the B bath is not a good idea. Low agitation in B is best.
The sludging might be due to the fact that this developer may have been designed as a single shot and therefore reusing "B" is a no-no. IDK for sure, but adding a sequestrant to part B might be useful.
The sludge is silver.
You need a full liter mixed to get a normal development.
Missing one of B ingredients would also exacerbate the underdevelopment, if you did forget one it's likely the Sodium Sulfite else you wouldn't get the sludge. There should be some sludge in the A as well.
3min in bath a is too short for the film you used try 5 and 3.
For some recent emulsions you might be better off just mixing A and B. As PE said, a lot depends on the thickness of gelatin to hold enough A to be activated by B. The T-grain emulsions flat grains allow thin emulsions, a fact that contributes greatly to resolution and acutance, but makes it hard on divided developing.
I used divided developers for a while many years ago, and they performed very well. They are much less fussy than the standard type. But when I tried them again a couple of years ago, I had trouble. Like you, I got thin, inconsistent results. It seems that divided developers just do not work well with modern films. It may have something to do with the superhardened emulsions. PE also makes an important point - divided developers work differently with different films. That is especially true with modern films, and some people report good results with one or another brands. You can experiment with different times, especially in the first solution, and you may find something that works well for your particular film. But, in general, I can't recommend these developers for moder films.
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I've tried all of the DD's in "Darkroom Cookbook" and most in FDC. Yes, results do vary from one DD to another and from one film to another.
You can try D2D in TDC, that's the best IMHO. There's HQ, Borax and Carbonate a work in there. I've gotten some good negs from it, but, there's always a BUT, you may have to custom tweak the carbonate level to suit you contrast needs.
Sludge is normal. I dump after 6 rolls, although some directions sate good for 20.
D23D is a good one, but I've upped the level of metol in A. I'll try to look it up for you.
DD's can be fun and useful, but you may waste a lot of film and time getting it right.
Ahh yes, the ol Post-It notes attached to the inside of the book! My notes tell me that I upped the metol in D-23D to 7.5g and doubled the carbonate to 9g. I show times of 4 min in "A" and 8 min in "B".
Thornton's Two Bath is a DD I like quite a bit, but this was created with thinner emulsions in mind.
Adam's Divided (FDC) is another that works, but for some reason I got really grainy negs; haven't used it since.
Testing is advised!
After twenty years, on and off, of experimenting with many DD's, I'm starting to get a handle on some aspects. No, more than a handle. I will be writing up some of my findings very soon, it's in progress. Here are a few pertinent points.
1. DD's work just fine with modern emulsions. You just need the right DD. See #4.
2. Don't confuse regular developers like D-23 that get finished off in a Bath B. Actually, Diafine is one of them because the Phenidone is quite active at the Bath A pH.
3. Absolutely minimize agitation in Bath B, use just enough to be rid of streaks and drag.
4. Probably my greatest discovery, hinted at above, is that the reactivity of different films to different developers is the reason that certain DD's work so well with some and not with others. I have come up with three categories and they each need their own developer!
5. The pH of Bath B has little outcome on the image. High pH baths develop faster and if left in solution too long, grain increases. Otherwise, no difference.
6. The amount of chemistry in Bath A does not make as much difference on contrast and density as you would think. Some, yes. But very little
I'll be "publishing" my observations in the next week or two with some formulas, film reactivity ratings, etc.
So, how much of what did you put into that half liter?
Originally Posted by srs5694
And BTW, 1/2 liter is plenty for A roll of 35mm. Dan
I think that I halved all the amounts, but of course I could be mistaken about this. I certainly wouldn't be able to use a whole liter for any one roll, since my largest tank holds just over half a liter of solution.
Thanks to everybody for their comments. I think I'll give up on the current batch, in case I mis-mixed it. I may try the D2D that Jim mentioned, but I'll need to track down the formula first.