Getting both good speed and fine grain with two baths?

[albada]

Here's another one of my ideas which must have been tried many times over the decades, but I've read nothing about it.
The goal is to achieve both high film-speed (more shadow detail) and very fine grain by developing a roll in two different developers, A and B:

Bath A: A speed-maximizing developer. Develop in this bath long enough to get a thin negative.​

Bath B: A very fine grain developer. Develop to normal contrast.​

The theory behind this idea is that the large amount of solvent in a super fine grain developer destroys many small latent image specks (reducing speed), so we first make those specks bigger in bath A before subjecting them to the solvent in bath B. The result is hopefully both good speed and very fine grain. Is anyone aware of work on such a pair of developers?

All two-bath developers I'm aware of contain an alkali in bath B to activate the developer that soaked into the emulsion in bath A. The idea above is entirely different. But will it work?

Mark

 

[john_s]

Over many years I've tried quite a few developers, maybe 20 all together, some rather ignorantly in my early years (e.g. Rodinal with the Agfa 800 speed film of the 1960s). Now I'm relieved that that I've settled on two that serve my purposes well, Pyrocat-HD mostly, ID-68 for low light hand held situations.

The thought of trying several developers in various combinations fills me immediately with a feeling of impending exhaustion.

However, it's an intriguing idea, and I might give it a try, using my two developers.

 

[Sirius Glass]

Interesting, I will wait and twiddle my thumbs while this thread develops.

 

[John Wiegerink]

I'm pretty much like john_s above in that I have my main two, Xtol-R and Pyrocat-HDC, but I'm not close-minded to other developers. It's just that those two are my "bread and butter" or "tried and true" developers.
I just got done playing with Stoeckler's two-bath and found it very educational. I used the method in the writing on "Stoeckler's two-bath by James M. Kates". He explains how this two-bath and maybe other two-bath developers can even be used by Zone System workers. Two-bath developers certainly have their place, but might not be the best at everything, in the same way I find Xtol-R.

 

[bluechromis]

This is confusing because I have read that solvents can increase film speed by uncovering new development sites. Anchell in the Film Developing Cookbook says that Ilford's Microphen can produce a 1/2 stop speed increase. In the ID-68 formula that he says is comparable to Microphen, there is a fair amount of sulphite, 85 g./liter. That is a bit less than with D-76 (100 g). Another speed increasing developer, FX-37, has only 60 g/liter of sulfate. But is the speed advantage of Microphen mainly due to less sulphite (solvent effect) or to the use of Phenidone instead of Metol?

Diluting certain developers is said increase film speed which seems to corroborate idea that greater solvent reduces speed. But then using developers that have no sulfate, like some ascorbate developers, would seem to offer the greatest speed boost, but that seems not to be the case. Anchell and Troop say that high definition developers like FX 1, FX 2 and Beutler typers usually have modest amounts amounts of sulfite, sometimes under 30 g/L. These developers are able to achieve speed increases, in part, by using dilute solutions that create local exhaustion in highlight areas. But Rodinal, they claim, cannot increase speed, possibly because, "...the sulphite content may be too low (some sulfite is needed to uncover latent image centers that a pure surface developer would leave underdeveloped." From this, it seems that maximizing film speed involves both dilute solutions to promote compensating effects and a modest solvent action. But high definition developers do not have fine grain.

It is a question how Xtol type developers achieve both a speed increase and fine grain without resorting to high dilutions.

 

[John Wiegerink]

This is confusing because I have read that solvents can increase film speed by uncovering new development sites. Anchell in the Film Developing Cookbook says that Ilford's Microphen can produce a 1/2 stop speed increase. In the ID-68 formula that he says is comparable to Microphen, there is a fair amount of sulphite, 85 g./liter. That is a bit less than with D-76 (100 g). Another speed increasing developer, FX-37, has only 60 g/liter of sulfate. But is the speed advantage of Microphen mainly due to less sulphite (solvent effect) or to the use of Phenidone instead of Metol?

Diluting solvent developers like D-76 is said to increase film speed which seems to corroborate idea that greater solvent reduces speed. But then using developers that have no sulfate, like some ascorbate developers, would seem to offer the greatest speed boost, but that seems not to be the case. Is that because they tend to be high pH? Maybe there is a happy medium of solvent effect that does the best.

Anchell and Troop say that using dilute high definition developers that create local exhaustion in highlight areas benefits film speed. But this seems to be a different effect than that of reducing solvent action by dilution.

Maybe it's more about finding that "just right" combination or that "perfect balance"? I don't know the answer, but I do know that Diafine certainly gives me a "speed boost" with certain films and not so much with others. Must be that "right combination" thing working.

 

[Alan Johnson]

You could try it using Beutler followed by Perceptol.
But carry over from part A would slowly increase the pH of part B.

 

[albada]

I found a reference in the literature to something similar to my idea. In Haist, vol 1, page 424:

In other cases development may be started in a weak developing solution and finished in another of different activity.​

That's all he says about it, aside from a reference to an article from the 1890s. The remainder of the section on divided developers is devoted to the common case of part B being the alkali. My purpose in asking is to avoid wasting time on an idea that others have discovered is a dead end. But it appears that this approach has been explored little.

 

[relistan]

Mark this is interesting. I think you might want to do an abbreviated wash in between the two developers. You don’t need (or want) carryover in the second bath. By washing you can keep from polluting the second developer. Experiments by @Alan Johnson annd others showed that carryover is typically 15-20ml, and I replicated this. That can make a big impact pretty fast.

 

[relistan]

This is confusing because I have read that solvents can increase film speed by uncovering new development sites. Anchell in the Film Developing Cookbook says that Ilford's Microphen can produce a 1/2 stop speed increase. In the ID-68 formula that he says is comparable to Microphen, there is a fair amount of sulphite, 85 g./liter. That is a bit less than with D-76 (100 g). Another speed increasing developer, FX-37, has only 60 g/liter of sulfate. But is the speed advantage of Microphen mainly due to less sulphite (solvent effect) or to the use of Phenidone instead of Metol?

Diluting solvent developers like D-76 is said to increase film speed which seems to corroborate idea that greater solvent reduces speed. But then using developers that have no sulfate, like some ascorbate developers, would seem to offer the greatest speed boost, but that seems not to be the case. Is that because they tend to be high pH? Maybe there is a happy medium of solvent effect that does the best.

Anchell and Troop say that using dilute high definition developers that create local exhaustion in highlight areas benefits film speed. But this seems to be a different effect than that of reducing solvent action by dilution.

It seems that solvents can help with a speed increase. But IMO they are not the only way it can happen. And you can overdo the solvent and not get an increase. @albada and @Alan Johnson recently pointed out that a couple of Crawley’s other speed increasing developers don’t use much solvent at all.

 

[albada]

You could try it using Beutler followed by Perceptol.
But carry over from part A would slowly increase the pH of part B.

I like this approach of Beutler+Perceptol. Because part A should produce a thin negative, I think diluting Beutler would help, which might boost film-speed as well.
And @relistan 's idea of adding a rinse between parts A and B would eliminate most carryover from A to B.

@bluechromis : I too am wondering how much sulfite to use in a speed-maximizing dev. You're right: It's around 3-5 g/L in Beutler and FX 1, and much more in FX 37. I envision an experiment in which 2/4/8/16/32/64 g/L of sulfite is added, adjusting alkali to keep pH the same, and then selecting the one that gave highest film-speed.

The FDC also mentions that poor buffering tends to boost speed by suppressing development in dense areas, so shadows develop more. That makes me think that setting pH with a small amount of NaOH (sodium hydroxide) instead of carbonate or borax would help speed. And poor buffering could be another benefit of having a small quantity of sulfite. Sharpness would also increase, so after the super fine grain dev in part B does its job, perhaps sharpness will remain good as well. Sharpness is poor in traditional super fine grain soups.

 

[bluechromis]

My understanding is that the grain-softening effect attributed to solvent developers is only partly due to dissolving (erosion) of the edges of film grains. The other cause is a replating of dissolved silver back onto the emulsion. Maybe the dissolving effect is more detrimental to film speed than replating because it destroys the small latent imagine regions. Could there be a way to enhance the replating effect and minimize the erosive effect?