Two bath film development queries

I have to agree with PE on one thing (finally ) emulsion thickness is important. I have tried 2-bath devs with some microfilms pressed into service as pictorial but becuase it would seem that the very nature of the thin coating on these films means that not enough Bath A is absorbed to give the softening effect sought.

True this is perhaps an extreme example, but I can see how it might also cause a failure with other film described as pictorial but having very thin coatings close approaching that of microfilm. How do the so-called TP replacements go in 2-bath?

Murray

sanking said:

PE,

Actually my own experience suggests otherwise. I tested several traditional emulsion and T-grain emulsion films and found that *most* of them developed to about the same average gradient, and same curve type, with the same time of development.

I did find one anomaly in the tests, though, and that was Ilford FP4+, a traditional emulsion type film.

What I have found to give very inconsistent results is water-bath development.

Sandy

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Sandy;

The operative word above is *most* and the fact that FP4+ did not work. I would hazard a guess that soft films and hard films would fare the worst by being the most different when using the same process conditions.

I did not say that they would fail absolutely, but rather that the process would have to be adjusted for each film individually rather than finding one condition that pretty much suits all. OTOH, the developer might have to be altered according to silver halide level, hardness and thickness.

So, my question would be to you... "how much difference in process conditions in the two bath developers were needed with each film when compared to a single bath development?" This data would be more revealing than a blanket statement. A given film to meet your criterion stated above might have needed 2x the time in the first solution or 2x the developing agent as a simple example when compared to other films, but it might then have "worked" by your definition.

PE

PE,

I did not say that FP4+ did not work. It worked fine in the two-bath developer but the average gradient was somewhat higher than with the other films I tested when developed for the same time and temperature. However, there was still a definite end point to the development of contrast, which is determined primarily by how much reducer the film emulsion can absorb during the first bath. I agree that the softness or hardness of the emulsion should in theory play a major role in this, but in practice there is more consistency between films than I would have expected, assuming the temperature of the solutions is over about 72F.

As for the issue of consistency, all of the films developed to an average gradient of between .45 and .49 with the same conditions and time of development. FP4+ was within that range, but getting there required reducing time of development by about 20%.

Bear in mind that my goal in this case is not to produce a negative with an exact average gradient, but one that is low enough in contrast to scan well. It is true enough that this condition could be met by reducing time of development with a regular one solution bath, but that would come at the cost of reduced film speed. Two bath development gives box speed, or more than box speed, for some of the same reasons that reduced agitation with dilute solutions also gives box speed +.

Sandy King

Photo Engineer said:

Sandy;

The operative word above is *most* and the fact that FP4+ did not work. I would hazard a guess that soft films and hard films would fare the worst by being the most different when using the same process conditions.

I did not say that they would fail absolutely, but rather that the process would have to be adjusted for each film individually rather than finding one condition that pretty much suits all. OTOH, the developer might have to be altered according to silver halide level, hardness and thickness.

So, my question would be to you... "how much difference in process conditions in the two bath developers were needed with each film when compared to a single bath development?" This data would be more revealing than a blanket statement. A given film to meet your criterion stated above might have needed 2x the time in the first solution or 2x the developing agent as a simple example when compared to other films, but it might then have "worked" by your definition.

PE

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Sandy;

I don't dispute your reasons nor your results. I'm sorry for the misquote.

I am saying that if you took a thick soft film, and a thin hard film as two extremes, they could develop one way in a single bath developer but work entirely different in a two bath developer. And, there are all possible results in between. So, your statement did not address what your extremes were, nor how they performed. Knowing that you reduced contrast from the norm of about 0.6 to around 0.49 does impact on the question of whether the two bath developer could give the "normal" result with "normal" conditions.

I'm glad that Murray has finally agreed with me.

PE

dancqu said:

Are there other than two bath developers
being marketed? Dan

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Is your question what two bath developers are being marketed today?

If so, in the US you can buy Diafine (widely available) and divided D76 (from the Photographers Formulary). Diaxactol, also available through the Formulary, was initially promoted as a two-bath developer, not sure if that is still the case.

Many developers formulated for single solution can be used as two bath, though one will have to work out the specifics of dilution and time of development. For example, I have gotten very nice results with Pyrocat-HD used as two bath, but the dilution of both A and B must be much stronger than when the developer is used as a single solution.

Sandy King

Did you use Diafine?

sanking said:

Is your question what two bath developers are being marketed today?

If so, in the US you can buy Diafine (widely available) and divided D76 (from the Photographers Formulary). Diaxactol, also available through the Formulary, was initially promoted as a two-bath developer, not sure if that is still the case.

Many developers formulated for single solution can be used as two bath, though one will have to work out the specifics of dilution and time of development. For example, I have gotten very nice results with Pyrocat-HD used as two bath, but the dilution of both A and B must be much stronger than when the developer is used as a single solution.

Sandy King

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For your tests and magazine article, that is. If not, what?

Paul Verizzo said:

For your tests and magazine article, that is. If not, what?

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For the magazine article I tested Diafine and divided D-23. The D-23 formula was the Ansel Adams version that uses sodium metaborate as the accelerator, not borax. I chose D-23 over divided D-76 for the tests because the article is in a large format magazine and with large format film sharpness is usually more important than grain.

Sandy King

Good choices, Sandy!

sanking said:

For the magazine article I tested Diafine and divided D-23. The D-23 formula was the Ansel Adams version that uses sodium metaborate as the accelerator, not borax. I chose D-23 over divided D-76 for the tests because the article is in a large format magazine and with large format film sharpness is usually more important than grain.

Sandy King

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I'm sure you realize that divided D-23 (and many others) are more hybrid than really divided. Some developing does take place in the first bath, generally, and can be a control feature.

But Diafine is pretty much nothing in Bath A unless there for a long time.

I think a lot of the discussion about DD's over the decades has been flawed because both of these types are conflated into one.

Yes, I understand that some development takes placed in divided D-23 from the presence of sodium sulfite. However, the density that is produced in 3-5 minutes in Solution A is relatively quite low compared to what happens when the metaborate kicks in. I know this for a fact since I actually pulled and fixed a step wedge negative after five minutes in Solution A. Transmission Dmax at that time was very low, though I don't remember the exact number.

I agree that there is a lot of flawed information in the literature about divided developers, much of it due to the specific fact that you have observed.

Sandy King

Paul Verizzo said:

I'm sure you realize that divided D-23 (and many others) are more hybrid than really divided. Some developing does take place in the first bath, generally, and can be a control feature.

But Diafine is pretty much nothing in Bath A unless there for a long time.

I think a lot of the discussion about DD's over the decades has been flawed because both of these types are conflated into one.

Click to expand...

I have done a half-assed two bath technique for some things. It worked quite well. Basically, it is like developing the shadows and the highlights separately. It takes a ton of testing. I figured out how to get a pretty normal development, and experimented with pulling. For the first bath I just used water and metol. The second bath was water and Kodalk...I think. The film was Tri-X 320 sheets.

sanking said:

Is your question what two bath developers are
being marketed today?

Many developers formulated for single solution can
be used as two bath, ... Sandy King

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We know there are many one bath only developers.
Your comment though was such a ringing endorsement
of two bath developers. How will the others ever
survive?

An issue of Camera and Darkroom some years ago had
an article by Steve Anchell detailing the use of two bath
developers plus a few formulas. If any are interested
I'll pin down the issue.

In very few words two of a few issues he presented:
Less active A baths with the use of Bisulfite and multiple
pass processing by use of an intermediate rinse.

I'm entirely satisfied in my own mind that very dilute one
shot chemistries such as Rodinal or HC110 will work well
using multiple pass processing. The B bath also very
dilute and containing some choice of alkali.
So, one-shot, two-bath. Dan

dancqu said:

We know there are many one bath only developers.
Your comment though was such a ringing endorsement
of two bath developers. How will the others ever
survive?

Click to expand...

You appear to have read more into my message than I said.

I have for a very long time promoted rigid exposure and development methods based on Zone and BTZS. That is wonderful if you are printing in the darkroon and need a negative with a precise density range for a process with a specific exposure scale.

However, if one is exposing and developing to scan there is no need for that level of precision. You need a well-exposed negative that will develop to a fairly low average gradient, and no more. My opinion is that two bath development does this as eficientlly as any other method I am familiar with. If you know a better method write an article about it. I would be interested.

Sandy King