Using 2-bath Pyrocat

[Steven Ruttenberg]

My initial trial worked great

1:15 developer A 6min 30sec at 71 degrees F
1:15 developer B 6min 30sec at 71 degrees F

Then typical stop, fix, hypoclear, rinse 10 min

Would a variation of concentrations help with the highlight development?

Since it is the amount of developer A absorbed into the film prior to solution B, would different strengths for A and B work? Say 1:100 for A, develop for say standard time for this dilution, then go to B at say 1:15 or 1:20 and develop for 6-10 minutes to further bring out shadow detail? From what I understand, the development in B for highlights is almost instantaneous whereas the shadows continue to develop, so If can better work on retaining the highlight detail while bringing out shadows that would be a plus.

The second method I am going to try shortly is to bleach the film prior to putting into the pyrocat. I will start with 1:15 or 1:20 for the A and B of pyrocat at 6-7 minutes each at 70-75 degrees as a base point, and then alter from there if need be. I will also compare the development of the film after bleaching using Tmax developer to start. After that I will try a different developer.

But for now, my main interest is optimizing the 2-bath Pyrocat for my style of shooting.

[koraks]

Say 1:100 for A, develop for say standard time for this dilution, then go to B at say 1:15 or 1:20 and develop for 6-10 minutes to further bring out shadow detail?
That will likely result in a very, very faint image with insufficient density for printing due to the way too low concentration of the A bath for this purpose. If you want to play with it, try something like 1+25 for A. I would change only one variable at a time until you get a feeling for what each of the variables do. Otherwise, any unanticipated result will stump you.

Also, your post is a bit confusing. You are speaking of 'help[ing] with highlight development' whereas at the same time you say that you want to 'retain the highlight detail while bringing out shadows'. I assume going by your several other threads that you want to achieve fairly extreme compression. In that case, diluting the A bath may give you what you want, but since you also have to take into account the time it takes for the A bath to dissipate out of the emulsion when the film is in the B bath and you don't want your shadows to be undeveloped when that happens, you may have to make the B bath a little stronger to compensate for it. I'm not sure, give it a try. I see quite a lot of experimentation and fidgeting in your future, that's for sure.

I quite quickly gave up on 2-bath pyrocat as I found it easier to get good results with regular development and since the A bath will oxidize, it's a fairly wasteful approach. Maybe I'll give it another try in the future, but as it is, I don't really see a good use for it.

[Steven Ruttenberg]

What I mean by helping highlight development is that I want to develop the highlights to have detail (clouds, backlighting, etc) but not be blown out. While, at the same time ensuring that the shadow detail is well developed. When I start, I do plan to change only 1-variable at a time otherwise, I will get lost quickly as you say. I don't think it will be too much experimenting. As for the 2-bath approach, it seems to have worked well for me. What I may find is that it may be sufficient for my needs as is or with slight variation. The bleach method, is to try and help with the highlights further.

[Steve Sherman]

If you’re interested in preserving highlight detail while maximizing film speed you might look into a Reduced Agitetion form of film development. Less costly than 2 Bath PyroCat but just as time consuming with more consistent results.

[koraks]

I understand that you expose quite liberally to retain shadow detail. Perhaps you're overdoing it a little and pushing too much of the highlights onto the shoulder of the film? If your highlights are clouds in a blue sky, perhaps a yellow filter helps a bit.

[Steven Ruttenberg]

I also use a grad nd for the extreme shots. For example, my Grand Canyon shot would not be possible if I exposed the shadows any darker just to save some working room on the highlights. The canyon was exposed to zone v for the darkest area and then the highlights fell where they did. If I had used a grad nd on that particular shot, it would have been even better. Another very hard shot, is shooting Aspens during fall colors that are back lit. This is where the slimt will come in handy with color reversal film since 2-bath won't work, but there may be other methods. Here you can't use a filter and the metering has to be on the Aspen trunk and then pushed to zone vi.

The 2-bath pyro works good for me so far, but the cost is a bit high, unless I start making my own. I will look into the reduced agitation that is mentioned above. Right now, I am working on trying to figure out exactly the method I want to use that will give me what I am after. Open to all ideas.

[Steven Ruttenberg]

I understand that you expose quite liberally to retain shadow detail. Perhaps you're overdoing it a little and pushing too much of the highlights onto the shoulder of the film? If your highlights are clouds in a blue sky, perhaps a yellow filter helps a bit.

The can be cloud, storm clouds, sunsets/sunrises (especially hard to shoot to get canyon detail while not blowing sky out, why I use the grad nd), back lit subjects, etc. I don't think yellow will give me what I am after, but can try it.

[sanking]

Minimal agitation with dilute solutions will use less solution than 2-bath development, with perhaps more consistent results. However, with 2-bath development you can tame the results with the standard dilution and time of development (for the film in question) and all you must do is expose correctly, which means expose for the deepest shadows where you want detail. If you do that you should be able to expose and develop for any scene, even very high contrast, because highlight density is finite and limited, as determined by the amount of reducer absorbed by the emulsion in solution A.

With this method shadow density is determined by exposure, highlight density by how much reducer is absorbed. Your highlights with 2-bath should never be blown out, at least with the films and dilutions I recommend in the article on 2 bath Pyrocat. The main control in 2-bath Pyrocat is dilution of Solution A. The other three controls, time in A, dilution of B and time in B, are relatively minor. What you must get right, and this varies for films based on the nature of the emulsion is dilution of A, and exposure for shadow density.

Sandy

[Steven Ruttenberg]

Minimal agitation with dilute solutions will use less solution than 2-bath development, with perhaps more consistent results. However, with 2-bath development you can tame the results with the standard dilution and time of development (for the film in question) and all you must do is expose correctly, which means expose for the deepest shadows where you want detail. If you do that you should be able to expose and develop for any scene, even very high contrast, because highlight density is finite and limited, as determined by the amount of reducer absorbed by the emulsion in solution A.

With this method shadow density is determined by exposure, highlight density by how much reducer is absorbed. Your highlights with 2-bath should never be blown out, at least with the films and dilutions I recommend in the article on 2 bath Pyrocat. The main control in 2-bath Pyrocat is dilution of Solution A. The other three controls, time in A, dilution of B and time in B, are relatively minor. What you must get right, and this varies for films based on the nature of the emulsion is dilution of A, and exposure for shadow density.

Sandy

I do expose for the shadows for sure and started doing that when I learned of the two bath process.

If I read correctly, highlights are controlled by the amount of A that is absorbed prior to putting into solution B. Solution B then develops the highlights based on amount absorbed and will continue to develop the shadows after the highlights stop developing based on the exposure of shadow detail.

The more A absorbed the denser the highlights the less A the less dense. And dilution is main factor not time in dilution.

[sanking]

I do expose for the shadows for sure and started doing that when I learned of the two bath process.

If I read correctly, highlights are controlled by the amount of A that is absorbed prior to putting into solution B. Solution B then develops the highlights based on amount absorbed and will continue to develop the shadows after the highlights stop developing based on the exposure of shadow detail.

The more A absorbed the denser the highlights the less A the less dense. And dilution is main factor not time in dilution.

That is basically correct. However, exhaustion of the reducer in the highlights is quickly followed by exhaustion in the shadows so increasing time in Solution B does not result in much of an increase in the shadows and highlights. Beyond a certain point increasing time in Solution B results in an increase in overall film fog, or stain.

Sandy

[Steven Ruttenberg]

That is basically correct. However, exhaustion of the reducer in the highlights is quickly followed by exhaustion in the shadows so increasing time in Solution B does not result in much of an increase in the shadows and highlights. Beyond a certain point increasing time in Solution B results in an increase in overall film fog, or stain.

Sandy

Okay, gotcha. I was not fond of chemistry in college and now I need to know it. LOL