Pyocat-HD/-MC 2 Bath Developing...

[sanking]

Don't know if this helps you , but ColorGenius (Screen Cezanne) only saves in 8 bit when scanning in greyscale, but if I chose RGB positive it will allow 16 bit scans which I can invert and convert to greyscale. I'm certain if your Creo did the same you would have picked that up along the way. Just in case...

bob

Bob,

16 bit saves are not possible with the Eversmart scanning application that I use. Later versions of the scanner use oXYgen which allows 16 bit saves. But for my work with large format negatives, which I scan in 8 bit RGB and then convert to 16 bit before making a B&W conversion to Photoshop, I really don't believe that I am losing anything in terms of image quality compared to a straight 16 bit scan. And I have made careful comparisons of this work flow with a regular 16 bit work flow with another scanner.

Of course, with the Everesmart the analog to digital conversion is made in high (14) bit mode so if you prepare the pre-scan carefully there should be no need in the future of very drastic tonal corrections.

Sandy

[Cor]

I would like to steer away from scanning (in my own interest, I only print..;-)..).

What happens when you process a film shot on a dull day (so there is moderate/low contrast recorded) and you process that in in divided Pyrocat.

Does that scene get very (too) flat?

(I've read mixed opinions on that on APUG, but I might mix things up here, these comments were made in relation to diluted Pyrocat and semi-stand developemnt, I do not recall exactly..)

Best,

Cor

[Matus Kalisky]

... I scan in 8 bit RGB and then convert to 16 bit before making a B&W conversion to Photoshop, I really don't believe that I am losing anything in terms of image quality compared to a straight 16 bit scan. ...
Sandy

Sandy, I do my B&W scanning with my Microtek F1 the same way.

There seemed to have been quite a discussion which took a bit on its own direction. My main concern with flat scans (made from flat negative) was that after all the boost in contrast they may look a bit ... weird with more pronounced grain - at least compared to not so flat scan which was made from not so flat negative.

So - I tried to say that a flat scene which will be exposed a processed (developed) such that it will yield very flat negative may look less nice (or natural) as it would have been processed (developed) such that it would yield negative with a higher ("normal") contrast which would then in turn yield more contrasty scan.

[Bob McCarthy]

I really don't believe that I am losing anything in terms of image quality compared to a straight 16 bit scan. And I have made careful comparisons of this work flow with a regular 16 bit work flow with another scanner.



Sandy

Sandy, the 16 bit conversion (from 8) only impacts rounding errors in editing. Not even close to native high bit captures.

That said, it's also true that the difference between 8 bit and 16 bit scans/edits is small/minimal when working in greyscale. I believe you would feel very differently if you were scanning "color images".

bob

[sanking]

‘I would like to steer away from scanning (in my own interest, I only print..;-)..).”


Cor, that is perfectly fine, but if you need to develop film to a specific contrast for printing in the wet darkroom you might just as well take notes and use a single solution developer. There are ways to control contrast with two bath development but in most cases that would involve the same kind of note taking and pre-testing you would use with traditional single bath development. It is perfectly true that film exposed on a dull day will have less contrast then film exposed on a sunny day if developed in the same two bath development. There is no getting around that fact.

“My main concern with flat scans (made from flat negative) was that after all the boost in contrast they may look a bit ... weird with more pronounced grain - at least compared to not so flat scan which was made from not so flat negative.”

Matus, I don’t know what to say but what I have already said. Post processing of flat, normal and high contrast scans seems to give about the same image quality in my own work.

“Sandy, the 16 bit conversion (from 8) only impacts rounding errors in editing. Not even close to native high bit captures.”

Bob, that was exactly the point I made earlier, ie, converting an 8 bit file to 16 bit does not add more tones, but it prevents losing tones due to rounding errors. But this is not a trivial thing because it has much importance for how much editing you can do on the file.

Sandy

[David Karp]

Cor,

You can do it and print in the wet darkroom. I have not yet used Divided Pyrocat, but I have used both Diafine and Thornton's variety of divided D-23. With either you can get excellent negatives that print well traditionally. When photographing on an extremely dull and overcast day, you will get a negative that reflects that scene.

There are multiple choices if you want to add punch to the negative. First, you can just tone it in selenium toner diluted 1:1 for 5 minutes. This will give you the equivalent of N+1, and will have positive archival impacts as well.

Second, if you find you need more contrast, and you make backup negatives, just add more accelerator to the B bath, which is a method advocated by Barry Thornton.

Third, you can add more developing agent to the A bath, which I believe is something that Sandy has mentioned in the past.

Finally, you could combine one of these methods with the selenium toning to gain additional contrast.

I have several photos that have received many positive comments from really good photographers and printers that were taken in extremely dull lighting conditions and developed in a two bath developer. They print nicely on grade 3 paper. I have another that had to go to grade 4. They have nice rich blacks, and even a since of light that was not really present in the scene when the photograph was made. Try it out. You might like the results.

I do have one question: How much expansion can you really get with today's films? Can you get past N+1? N+2? Based on my experience, for the rare negative that needs enough expansion that a slightly higher than normal paper grade is not enough, then it is a simple matter to give the negative a bath in 1:1 selenium toner to get there without giving up the convenience and other benefits of a divided developer.

[Lachlan 717]

Getting back onto the topic somewhat, I am curious as to the way to determine development times for various film speeds.

It seems to me that (using VERY rough estimates) the Part A and Part B times seem about half of the original total time. In other words, 5 minutes (A)+ 5 minutes (B) = usual 1-bath development time.

So, my question is this: Is it a good starting point to split the total time (1-bath mix) by 2 for any given film and using that for Part A and Part B?

Say I'm using Efke 25 that would usually take around 5 minutes in a 1-bath Pyro mix. Should I do 2min 30sec for each of the fluids in a 2-bath?

[Jay DeFehr]

Lachlan,

2-bath development is different than single bath development. With 2-bath development,the first bath is an absorption bath- no development takes place (except in type A developers, like DD23). In the second bath, development is almost instantaneous, and is carried out to exhaustion. The effect is similar to print development, where development is carried out to completion, though the mechanisms are different. After the film is saturated in the first bath, increasing time, temperature, or agitation have no further effect. The only way to increase contrast is to increase the concentration. In the second bath, development is complete when the developer saturated in the emulsion is exhausted, which doesn't take long. Additional time in the second bath will not increase contrast.

[Lachlan 717]

Lachlan,

2-bath development is different than single bath development. With 2-bath development,the first bath is an absorption bath- no development takes place (except in type A developers, like DD23). In the second bath, development is almost instantaneous, and is carried out to exhaustion. The effect is similar to print development, where development is carried out to completion, though the mechanisms are different. After the film is saturated in the first bath, increasing time, temperature, or agitation have no further effect. The only way to increase contrast is to increase the concentration. In the second bath, development is complete when the developer saturated in the emulsion is exhausted, which doesn't take long. Additional time in the second bath will not increase contrast.

Thanks, Jay. Looks like I'll be burning a couple of sheets as "practice"…

Lucky it's raining outside!

[Ken Lee]

Here's a better image that shows even more dynamic range: detail in the deepest shadows and no blocking of the high values, even at Zone XIV or higher.

It looks like a scene with controlled lighting, but it wasn't.

Even here, I actually had to increase contrast, bringing the low values down a bit, for aesthetic effect. But the data was all there.

Lately I have been looking for subjects like this to shoot