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

[venchka]

...for the technically challenged.

Sandy, Ken, etc.,

I think that I have read all of the threads on the subject. Would it be possible to state the procedure for using and relative merits of both developers in a divided, two bath scenario?
I am beating my head against a wall fighting summer heat here in Houston. I love Xtol 1:3, but the temperature variations between summer and winter are killing me. I want simple. Temperature independant. One soup fits all of my eclectic hodge podge of emulsions and formats.
My hardware setup is a Jobo 3010 Expert drum and 2553 tank and reels. These rotate in a single direction on either a Beseler or Uniroller motor base at 30-32 rpm. Ambient summer room temperture is 78°F to 80°F. Tap water is close 85°F. I prewash in tap water.
Please advise a starting point for the 2 bath method and which developer is correct for my current method. I am not a high volume user so long stock solution shelf life is important. Example: It took me 13 1/2 months to use up my last 5 liter batch of Xtol.
Dilution, prewash or not, wetting agent or not, time in each solution, type of fixer, etc. would help me a lot. Subject to my own testing of course.
Thanks for all of your help, past and future. I wouldn't be where I am today (still slightly dazed and a little confused) without your help.

[dng88]

Is this procedure can help to hanlde the high temp.? A lot of places in the world has this summer of 25c to 35c (77-95f or higher even in LA just recently). What is the limit of temp?

[sanking]

...for the technically challenged.

Sandy, Ken, etc.,

I think that I have read all of the threads on the subject. Would it be possible to state the procedure for using and relative merits of both developers in a divided, two bath scenario?
I am beating my head against a wall fighting summer heat here in Houston. I love Xtol 1:3, but the temperature variations between summer and winter are killing me. I want simple. Temperature independant. One soup fits all of my eclectic hodge podge of emulsions and formats..

To address your questions.

1. If you compare Xtol 1:3 with two-bath pyrocat this is what you would find, IMO. Grain is slightly finer with Xtol, film speed is slightly greater with Xtol, and sharpness is higher with two-bath Pyrocat.

2. Temperature control is less important with two-bath Pyrocat than with Xtol. Film will absorb more of the reducer at 85º F than at 75º F, and this will increase contrast slightly. But the mechanism of development still limits the development of highlight density.

3. I personally use two bath development with roll film that I expose when traveling. This allows me to expose film in a variety of subject brightness conditions and not have to worry about how long to develop the film. The other thing is that this method produces very high sharpness.

4. For development in Jobo with constant rotation I would recommend the following protocol.

a. Use a 1:15 or 1:20 dilution of Pyrocat Stock A and Stock B for most films. Add a few grams of PhotoFlo to the solution.
b. Pre-soak the film for two or three minutes in water at 75º F.
c. Develop for five minutes in working Solution A, at 75º F. Then drain the film for 15 seconds.
d. Develop for five minutes in working Solution B, at 75º F.
e. Use a 1/2 strength acetic acid stop bath for 10 seconds.
f. Fix in any standard fixer. I use an alkaline fixer (TF-3) but the use of a slightly acidic fixer is ok.
f. Wash the film for 10-15 minutes, drain and dry.

Bear in mind that I develop film for scanning, not for printing in the wet darkroom. This means I place more importance on limiting highlight contrast than on developing film to a given CI to match a certain paper or process.

Hope this information is useful.

Sandy King

[anotherJoe]

Quick question: Why 75ºF for 2-bath Pyrocat, as opposed to the 68ºF that I use for 'standard' Pyrocat rotary development?

I really want to give 2-bath Pyrocat a try, but am going to be challenged trying to maintain 75º F solutions in my plumbing-less basement darkroom up here in NH.

To use lower development temps, is it is simple as extending the time the film develops in both Solutions A and B? If so, I'm willing to experiment a bit to get the right times for 68º F. I use Pyrocat-MC.

Joe

[sanking]

Quick question: Why 75ºF for 2-bath Pyrocat, as opposed to the 68ºF that I use for 'standard' Pyrocat rotary development?

I really want to give 2-bath Pyrocat a try, but am going to be challenged trying to maintain 75º F solutions in my plumbing-less basement darkroom up here in NH.

To use lower development temps, is it is simple as extending the time the film develops in both Solutions A and B? If so, I'm willing to experiment a bit to get the right times for 68º F. I use Pyrocat-MC.

Joe

The warmer the solution the more the gelatin can swell. The more the gelatin swells the more the more reducer can be absorbed. Yes, this is time dependent so the film might absorb as much reducer in ten minutes at 70º F as at 80º F in five minutes.

You might find that 70º F at five minutes will give you the right amount of contrast, but if it does not either extend development time or increase the temperature of the solution. Increasing the strength of the dilution from 1:15 or 1:20 to 1:10 will also result in more reducer being absorbed, assuming you maintain the same time and temperature.

Sandy

[anotherJoe]

Your explanation makes perfect sense!

Gracias.

Joe

[dng88]

A bit worry about the amount of photo flo in job drum. Is that ok? I was kept on being told, in this forum in fact, that it would affect the reel and in fact the drum.

If that is ok, how much as I am not sure the gram part. Also, is that go to solution A and by the way why?

Thanks in advance for any further advice.

[sanking]

A bit worry about the amount of photo flo in job drum. Is that ok? I was kept on being told, in this forum in fact, that it would affect the reel and in fact the drum.

If that is ok, how much as I am not sure the gram part. Also, is that go to solution A and by the way why?

Thanks in advance for any further advice.

Someone else will have to address the issue of Photoflo affecting the reel.

However, the reason for the Photoflo is that development of the film is almost instantaneous in Solution B. If the film does not drain evenly after removing it from Solution A you may get uneven development marks. Adding a few drops of PhotoFlo will optimize draining flow, and minimize or eliminate the risk of uneven development marks.

Sandy King

[dng88]

Thanks. May I assume to add to both solution A and B for the few drop of photoFlo?

[sanking]

Thanks. May I assume to add to both solution A and B for the few drop of photoFlo?

There is no need to add Photoflo to Solution B.

Sandy

[dng88]

Just want to nail it -- add the photoflo at step a i.e. as part of solution A or add it just in the middle of step c i.e. before draining.

Sorry to trouble you again.

Dennis Ng

[venchka]

Many thanks Sandy! That is exactly the kind of starting point information I need. I also develop for scanning and shoot roll film in 135 and 120.
I can certainly have the A and B solutions at 75°F when they are poured in the Jobo drum or tank. The temperature will rise a little during the 5 minutes of film contact. I can adjust time and dilution accordingly.
A friend of mine spent 2 years in Peru on a dig. No electricity. No temperature control. He used Diafine.
Off to order some Pyrocat-MC.

[sanking]

Just want to nail it -- add the photoflo at step a i.e. as part of solution A or add it just in the middle of step c i.e. before draining.

Sorry to trouble you again.

Dennis Ng

You can add the Photoflo at the beginning, as part of Solution A, or you could add it later, so long as you add it before draining and placing the film in Solution B. I always add it at the beginning, when I mix working Solution A.

Sandy

[dng88]

Many thanks!!!

[venchka]

A bit of clarification:
I can get my chemicals to any temperature I choose. The problem becomes maintaing that temperature in the Jobo drum during development. If I start at 68°F (or even less), the temperature of the developer rises at least 4° in the first 3-4 minutes of development when the ambient temperature is 77°F-79°F. It has been so hot this summer that the A/C won't cool my apartment below 77°F. At that temperatue, my times are getting uncomfortably short.

[dng88]

Thunking about blue ice bag. Thinking about trying 24c (75f) setting of jobo cpe/CPA (but not atl-1500 as hard to control external per-soak). Instead , use water pre-soak from bottle in the jobo water bath when it reach 24c after jobo warm up the blue ice bag in the water bath.

Then only the washing would be done at 29c.

Do you think it would work?

[sanking]

I would not worry about ambient temperatures when processing in a Jobo with two-bath Pyrocat. The mechanism of development itself serves to limit the range of contrast even with variations in temperature. I would just use a pre-soak at the temperature of your Solution A and not worry about ambient temperature. And temperature makes even less difference in Solution B.

So basically if the ambient temperature causes a rise of a few degrees of the solutions during the course of development this will not change final negative contrast very much.

Sandy

[venchka]

I would not worry about ambient temperatures when processing in a Jobo with two-bath Pyrocat. The mechanism of development itself serves to limit the range of contrast even with variations in temperature. I would just use a pre-soak at the temperature of your Solution A and not worry about ambient temperature. And temperature makes even less difference in Solution B.

So basically if the ambient temperature causes a rise of a few degrees of the solutions during the course of development this will not change final negative contrast very much.

Sandy

Exactly why I want to give this method a try.

[Ken Lee]

I hope a little more enthusiasm for Divided Pyrocat is not unwelcome. This post prompted me to perform an experiment: a photo made under mid-day Sun on a cloudless day - something I haven't done with a View Camera in decades, if ever.

With ordinary methods of exposure and development, adequate detail in both the shadows and high values would have been impossible. The shade areas would have been black and lifeless, or the sun-lit wall would have been white - but it was trivial with Divided Pyrocat.

I simply metered the shadow area and placed it on Zone IV. The high values fell way off the scale, but the 2-bath development process took care of that. The shadow area has full separation - a remarkable feat - as do the high values.

Sandy's suggestion of adding a few grams of Photo Flo to Solution A, has worked wonders: I now get perfectly even development.


http://www.kennethleegallery.com/images/forum/img007bdp.jpg
Massachusetts, 2010
Sinar P, 300mm Fujinon A
4x5 HP5+, Divided Pyrocat HD

[William Barnett-Lewis]

I've been using Diafine for all of my 4x5 development but have been considering giving a pyrocat version a try. I develop in a HP Combi-Plan daylight tank.

Is it possible to use that tank or do I need to go with something else? How much agitation would be needed?

Thanks!

William

[sanking]

I've been using Diafine for all of my 4x5 development but have been considering giving a pyrocat version a try. I develop in a HP Combi-Plan daylight tank.

Is it possible to use that tank or do I need to go with something else? How much agitation would be needed?

Thanks!

William


I think you should be able to use the Combi-Plan with two-bath Pyrocat. If it works with Diafine I think you should be ok with Pyrocat.

When I develop in tanks I agitate for a full minute at first in Solution A, and then for 15 seconds every minute thereafter. Be sure to add a few drops of Photoflo to Solution A. After finishing the time in Solution A drain for about 15 seconds.

I am not sure how you pour in the developer with a Combi-Plan, but if possible you need to remove the lid and pour in all of Solution B as quickly as possible. Then agitate continuously in Solution B for a minute, and for about 15 seconds every minute thereafter.

Sandy

[William Barnett-Lewis]

Ok, thanks for the information. I may have to experiment a bit, especially with the part b as it's a slow filling funnel job on this tank. Diafine doesn't care much about that. I'm working on convincing my wife that turning the walk in closet into a dark room is a good thing ;)

[sanking]

Sandy's suggestion of adding a few grams of Photo Flo to Solution A, has worked wonders: I now get perfectly even development.



Ken, how much Photo Flo are you really adding? I recommended a few drops, not a few grams!!

In any event, great results in your image of the barn.

Sandy

[Ken Lee]

Seriously, I actually added a few grams of PhotoFlo. It ended up being quite a few drops. See your post below:

"a. Use a 1:15 or 1:20 dilution of Pyrocat Stock A and Stock B for most films. Add a few grams of PhotoFlo to the solution."

Next time I'll try less. :)

[sanking]

Seriously, I actually added a few grams of PhotoFlo. It ended up being quite a few drops. See your post below:

"a. Use a 1:15 or 1:20 dilution of Pyrocat Stock A and Stock B for most films. Add a few grams of PhotoFlo to the solution."

Next time I'll try less. :)

Ken,

Thanks for the clarification. It was a mistake in my writing to say a few grams but if you added a few grams and it worked I will need to think about this again. But with Photo Flo a small amount goes a long way. I am just glad that a solution has been found to the problem.

Sandy

[venchka]

Ken, how much Photo Flo are you really adding? I recommended a few drops, not a few grams!!

In any event, great results in your image of the barn.

Sandy


Seriously, I actually added a few grams of PhotoFlo. It ended up being quite a few drops. See your post below:

"a. Use a 1:15 or 1:20 dilution of Pyrocat Stock A and Stock B for most films. Add a few grams of PhotoFlo to the solution."

Next time I'll try less. :)


Ken,

Thanks for the clarification. It was a mistake in my writing to say a few grams but if you added a few grams and it worked I will need to think about this again. But with Photo Flo a small amount goes a long way. I am just glad that a solution has been found to the problem.

Sandy

For the photograpically challenged.........

I own a very nice 10ml graduate that I use for measuring Rodinal at 1:100. Would 1ml per 500ml of Solution A be considered "a few drops"? Or should I actually use an eyedropper to measure 5-10 drops? I totally agree that a little Photo-Flo goes a long way. I only use about 3ml per 2 liters of water for a final rinse. I think I may have answered my own question. 1/2ml per 500ml seems about right. Eyedropper it is. Or a straw.

[sanking]

For the photograpically challenged.........

I own a very nice 10ml graduate that I use for measuring Rodinal at 1:100. Would 1ml per 500ml of Solution A be considered "a few drops"? Or should I actually use an eyedropper to measure 5-10 drops? I totally agree that a little Photo-Flo goes a long way. I only use about 3ml per 2 liters of water for a final rinse. I think I may have answered my own question. 1/2ml per 500ml seems about right. Eyedropper it is. Or a straw.

I personally don't bother to measure it. I just take the bottle of Photo Flo and pour a small amount into the cap, then add this to Solution A. I just did that to see how much it amounted to and I had a bit less than 1ml, which seems about right for a liter of Solution A.

Sandy

[venchka]

Thanks Sandy! Eyeball it is!

[William Barnett-Lewis]

(add photo flo to shopping list)

Continuing my own questions from last night, is there any one of the versions of pyrocat that is better suited to use as divided developer? Original HD or the newer MC with metol? Or another I've missed?

I hope to acquire an Omega 4x5 enlarger soon but in the mean time will still need to scan my negs as well as contact printing them, so my goal is a process that will work at least reasonably well with all three processes. From my reading of your work, I think this could make a really good starting point. Thank you for the help!

William

[sanking]

(add photo flo to shopping list)

Continuing my own questions from last night, is there any one of the versions of pyrocat that is better suited to use as divided developer? Original HD or the newer MC with metol? Or another I've missed?

William

As far as I can tell there is no difference in result between any of the Pyrocat versions in two-bath development. -HD seems to work the same as -MC, and although I have not tried the -P version I am highly confident that it would give similar results.


Sandy

[Jim Noel]

If you are putting Photo-flo in your Jobo, or any other drum, the next problem for which you will be seeking an answer is why the edges of the film are over-developed. Photo-flo becomes a catalyst as it builds up on on the tank, which it will.

[sanking]

If you are putting Photo-flo in your Jobo, or any other drum, the next problem for which you will be seeking an answer is why the edges of the film are over-developed. Photo-flo becomes a catalyst as it builds up on on the tank, which it will.

Is there no remedy for the build up of Photo Flo?

Sandy

[venchka]

Steel wool perhaps? Facetiously grinning.
Since Pryocat in all of it's various forms is a staining developer, isn't the stain being applied to the tanks, reels and drums as well? Are these a problem? Surely good cleaning practices will at least prolong the lifespan of the tankage and reelage.
Or should we all just go straight to digital?

[Mark Sampson]

Here's the method I learned for removing Photo-Flo residue from tanks and reels; a regular 'purge' in 100F water for 10 minutes or so. That was the weekly practice at the custom lab where I worked, c.1978. (I processed around 100 rolls of b/w a week there). As I use pyro developer in a tray, I can't say anything about stain buildup on reels; perhaps an acid, stop-bath type rinse might remove any that remains.

[Jay DeFehr]

I have many stained reels and tanks that work exactly like my many unstained reels and tanks. I wash my tanks and reels in hot water after each use, and have never seen any build-up of anything. Maybe I'm just lucky!

[Barry Trabitz]

What type of agitation for those of us who do not have a Jobo, but use trays.

[Ken Lee]

I do tray development* , and follow these instructions (http://www.pyrocat-hd.com/html/mixing.html#divided).

The first step is basically "uptake" of the Solution A into the emulsion: you want the film to absorb it fully, and agitation helps that. PhotoFlo helps it happen evenly.

The second step is where the developer gets activated, and where compensation occurs because it becomes quickly exhausted in the highlights but proceeds in the low values. You want to agitate enough to get the activator to the emulsion, but not so much as to disturb the compensating effect. That's why intermittent agitation is best in Solution B.

* Actually, I use plastic food containers (http://www.kennethleegallery.com/html/tech/devtray.html): much cheaper and better for 4x5 and 5x7 sheets. It's also helpful rotate the containers: One time a particular tray might get used for fixer - the next time for developer, rinse, whatever. They don't get stained at all that way: no problems with PhotoFlo or any other residue.

[gevalia]

Ken,

The instructions at http://www.pyrocat-hd.com/html/mixing.html#divided you referred to are missing dev times for A and B.

Ron

[Ken Lee]

"The instructions at http://www.pyrocat-hd.com/html/mixing.html#divided you referred to are missing dev times for A and B."

Here is what it says - with emphasis on the times. Are you referring to something else ?

1. Water bath for five minutes.
2. Six minutes in Part A, with two inversions at the beginning, and two inversions at the 1/4, 1/2 and 3/4 points of development.
3. Pour our Solution A and pour in Solution B. No rinse between. Five minutes in Solution B.
Negatives must be fully immersed in Solution B and agitated vigorously for at least one full minute. Failure to do so, can result in uneven development. Two or three inversions at the 1/4, 1/2 and 3/4 points of development.
4. Pour out B, pour in water and leave for five minutes.

[Sirius Glass]

Sandy, I see that you do not talk about using Solution A as a stain after fixing. I have seen a lot of discussion about this but never a clear explanation of "To stain or not stain?".

Steve

[Jay DeFehr]

Barry,

Since no development takes place in the first bath, there's no reason not to agitate continuously, and since development in the second bath is practically instantaneous, I think it's important to agitate continuously for at least the first 30 seconds, or so. After the first 30 seconds, I don't think it matters much whether you agitate, or not. This is based on my experience developing ortho film in a single tray, under a safelight. Nothing happens in the first bath, except that the backing dye is washed away, and the emulsion absorbs the developing solution. The film is completely clear after the first bath. When I pour the second bath into the tray, development is almost instantaneous, very similar to what one sees with WPC development. After 30 seconds, not much that's obvious happens. There might be a measurable increase in contrast after the first 30 seconds of development, but I doubt it's significant.

[sanking]

Sandy, I see that you do not talk about using Solution A as a stain after fixing. I have seen a lot of discussion about this but never a clear explanation of "To stain or not stain?".

Steve

I have always recommended against using the spent developer to increase stain after fixing. The reason is that the after stain increases general, or B+F stain, but does not increase proportional stain. This basically just increases printing density, with no beneficial effect at all.

Sandy

[Sirius Glass]

thanx

[sanking]

Barry,

Since no development takes place in the first bath, there's no reason not to agitate continuously, and since development in the second bath is practically instantaneous, I think it's important to agitate continuously for at least the first 30 seconds, or so. After the first 30 seconds, I don't think it matters much whether you agitate, or not. This is based on my experience developing ortho film in a single tray, under a safelight. Nothing happens in the first bath, except that the backing dye is washed away, and the emulsion absorbs the developing solution. The film is completely clear after the first bath. When I pour the second bath into the tray, development is almost instantaneous, very similar to what one sees with WPC development. After 30 seconds, not much that's obvious happens. There might be a measurable increase in contrast after the first 30 seconds of development, but I doubt it's significant.

If you agitate the film continuously in Solution A it will absorb more reducer (at a given time and temperature), which will increase contrast. That is why I recommend diluting the working solutions by 1/2 when rotary processing in tubes or jobo. This will give about the same contrast as normal strength with intermittent agitation.


As Jay mentions development is almost instantaneous in Solution B and there should be no increase in contrast after about 30 seconds. However, shadow density may increase very slightly with longer time because the reducer exhausts slower in areas of low density.

Sandy Kint

[Jay DeFehr]

I've always thought the idea was to saturate the film with the first solution, and adjust contrast by the concentration of the solution. I suppose there's more than one way to skin a cat!

[sanking]

I've always thought the idea was to saturate the film with the first solution, and adjust contrast by the concentration of the solution. I suppose there's more than one way to skin a cat!

Varying the concentration of Solution A is the most efficient way of increasing or decreasing final contrast, but within limits the temperature of the solution, time of development, and type of agitation will all influence how much reducer the gelatin emulsion is able to absorb.

I would suggest that if one needs to make a fairly significant change in contrast for a given film it would be best to increase of decrease the strength of the concentrate of solution A, for smaller changes increase or decrease the temperature or change the time of development.

Sandy

[Ken Lee]

http://www.kennethleegallery.com/images/forum/img012.jpg

Here's another experiment in extreme lighting: white porcelain in full sun shining through a window into a dark room. The high values fell on Zone XIII and higher.

The petals of the sunflower are actually a deep yellow - Zone V normally - and the stem is a medium green - Zone VI - but exposing for the shadows, has crowded the middle and high values together at the top of the scale.

Even so, you can see the difference between white porcelain and the specular highlight of the sun, which was Zone 99

[Marko Trebusak]

OK, I'll jump inn as well: I have a nice box of Efke 820 4x5 film sitting in refrigerator waiting for me to figure exposure and development out before deciding what to do with IR photography. Now for the question for those in know: would this method be good for something as unpredictable as IR photography with Efke film (especially for a beginner like myself)? I was thinking about developing by inspection with #3 green filter until I figure it out, but this sound even more simple.

Thanks,
Marko

[venchka]

One way to know for sure. Expose a few sheets and fine tune your method. Worst case: Use the Pyrocat with conventional Efke film.

[Matus Kalisky]

I have one relatively elementary question. as this process as described ( and proved by Ken with his photos) has a very strong compression effects - does not it yield very flat negatives if they are not of high contrast scene?

I use Pyrocat-HD as one bath developer and it already can do a lot to save the highlights. Sometimes the negatives can be quite flat and after scanning require substantial boost in contrast (as the raw scan occupies only rather narrow part of the total range) - what may yield in loss of smoothness in the tones and brings up the grain as well.

So - how do you post process your images?

[sanking]

I have one relatively elementary question. as this process as described ( and proved by Ken with his photos) has a very strong compression effects - does not it yield very flat negatives if they are not of high contrast scene?

I use Pyrocat-HD as one bath developer and it already can do a lot to save the highlights. Sometimes the negatives can be quite flat and after scanning require substantial boost in contrast (as the raw scan occupies only rather narrow part of the total range) - what may yield in loss of smoothness in the tones and brings up the grain as well.

So - how do you post process your images?

I post process with Photoshop and the primary mechanism for adjusting contrast is Curves. Unless you clip highlight or shadow tonalities in scanning or in making a curves adjustment you should not love any tonal values in making the curves adjustment. I also have not seen any problem with increased grain when adjusting curves, though I guess it is possible depending on what you start with and how abrupt your adjustment is. The main danger is making curve corrections is that if the correction is to drastic it may cause posterization, but this is pretty easy to see on the screen.

But primarily you just make sure to avoid clipping tonal values at both ends in making adjustments for contrast. Never use the Brightness/Contrast tool in Photoshop as this will nearly always clip tonal values.

Sandy

[Marko Trebusak]

One way to know for sure. Expose a few sheets and fine tune your method. Worst case: Use the Pyrocat with conventional Efke film.

Yes, I know. And will take your advice to the hart :D. I use Pyrocat as my only developer, but right now I'm collecting data to jump into IR photography. And I prefer not to invent "warm water", if someone was in my position before and is prepared to share his findings. ;).

Cheers,
Marko

[William Barnett-Lewis]

Hey, I'm watching to see what you find out. I've been eying that film for awhile (a bit of the 25 & a bit of the IR could be fun) so whatever you do learn, please make sure it get's posted somewhere on this site.

Thanks!

[Marko Trebusak]

Hey, I'm watching to see what you find out. I've been eying that film for awhile (a bit of the 25 & a bit of the IR could be fun) so whatever you do learn, please make sure it get's posted somewhere on this site.

Thanks!

Will do so, but it might take quite a bit of time :D.

Cheers,
Marko

[Matus Kalisky]

Sandy,

I indeed agree, however my concern about low contrast negatives that result in very flat scan is a bit different. A "very flat scan" shows itself very obviously when one opens the "levels" adjustments - as the whole image occupies only narrow portion of the 0 - 255 scale. Adjusting the black and white points stretches the existing tonal values (and of course increases the contrast) and may yield posterization.

So - my question could be put in a bit different way - how to properly adjust very flat (for what ever reason, actually) scans without destroying the tonalities. In darkroom one would use a higher contrast paper or filter (I guess).

[Marko Trebusak]

Sandy,
So - my question could be put in a bit different way - how to properly adjust very flat (for what ever reason, actually) scans without destroying the tonalities. In darkroom one would use a higher contrast paper or filter (I guess).

I'm not Sandy (obviously :)), but my answer would be: curves, curves, curves! Curve adjustment in Ps would increase contrast like VC filters would (in sort of way). If you have local problems, then tone masking is the answer (you will apply curve adjustment to only narrow tone scale). A coleague (http://goodlight.us/writing/tutorials.html) of mine have a cool tool for such a problem.

Cheers,
Marko

[Bob McCarthy]

I tried two bath developing for a while though it was D23 not pyro. I found if it fit the scene it worked great. But if the scene were more "normal" the negative was too flat and making a levels adjustment, while nominally appeared to work, it took on a harshness that I didn't like.

16 bit scans help somewhat,btw.

I only use a two bath process where appropriate.

Bob

[Bob McCarthy]

Sandy,

I indeed agree, however my concern about low contrast negatives that result in very flat scan is a bit different. A "very flat scan" shows itself very obviously when one opens the "levels" adjustments - as the whole image occupies only narrow portion of the 0 - 255 scale. Adjusting the black and white points stretches the existing tonal values (and of course increases the contrast) and may yield posterization.

So - my question could be put in a bit different way - how to properly adjust very flat (for what ever reason, actually) scans without destroying the tonalities. In darkroom one would use a higher contrast paper or filter (I guess).

I always thought hard papers with low contrast negatives looked a little funky too.

Bob

[sanking]

Sandy,

I indeed agree, however my concern about low contrast negatives that result in very flat scan is a bit different. A "very flat scan" shows itself very obviously when one opens the "levels" adjustments - as the whole image occupies only narrow portion of the 0 - 255 scale. Adjusting the black and white points stretches the existing tonal values (and of course increases the contrast) and may yield posterization.

So - my question could be put in a bit different way - how to properly adjust very flat (for what ever reason, actually) scans without destroying the tonalities. In darkroom one would use a higher contrast paper or filter (I guess).

Perhaps I am not understanding the problem. However, in my experience if you start with 255 tones in your scan and do not clip highlight or shadow tonality you should still have 255 tones when you increase the contrast of an image file with the curves adjustment. I have adjusted the contrasty of many image files of scans of very flat negatives without losing tonal values and without causing posterization. It is obviously important to work with 16 bit files (or change your 8 bit file to 16 bit) but expanding of compressing contrast should not reduce the number of total tones that you have unless you clip at the top or at at bottom.

Sandy

[Ken Lee]

I tried two bath developing for a while though it was D23 not pyro. I found if it fit the scene it worked great. But if the scene were more "normal" the negative was too flat and making a levels adjustment, while nominally appeared to work, it took on a harshness that I didn't like.

16 bit scans help somewhat,btw.

I only use a two bath process where appropriate.

Lately I've been working with Divided D-23. (Perhaps a better name would have been Dual D-23, since it is not a truly divided developer like Divided Pyrocat: development takes place in both A and B stages with DD-23, while with Divided Pyrocat, it only takes place in Solution B).

DD-23 is not as well suited to roll-film as Divided Pyrocat, because where we often shoot scenes of varied subject brightness range, and contrast control via development - and development by inspection - are inappropriate. For that, truly divided developers like Diafine and Divided Pyrocat come to the rescue. They develop all scenes within reason, to the same contrast index.

For scenes of extreme contrast, DD-23 doesn't produce "miracles" either, while Divided Pyrocat does.

For sheet film however, I like DD-23 for scenes of low to moderate contrast. Because development takes place in both solutions, you can use DD-23 to control contrast, while still getting some "extra" compensation afforded by the fact that developer gets extinguished in the highlights. Unlike other approaches, you can develop first for the high values in Solution A, and then for the shadows in Solution B. It gives full film speed and excellent shadow separation.

After restoring my membership in View Camera the other day, the first thing I did was download and read Sandy's article on DD-23 and Diafine - written, I presume, before his work with Divided Pyrocat.

[Bob McCarthy]

What it did do was rekindle a lost aquaintance with D23. Found I can use it very effectively with TMY-2 (1:1) and it produces very nice negatives.

As you say it is not a divided developer. I got to this point adjusting time in bath (1) to match contrast range - left bath (b) alone at 4 min. In the end for wide dr scenes, it was a simplified 4 min in (a) and 4 min in (B). For normal, I just use D23 1:1.

bob

[Wally]

Perhaps I am not understanding the problem. However, in my experience if you start with 255 tones in your scan and do not clip highlight or shadow tonality you should still have 255 tones when you increase the contrast of an image file with the curves adjustment. I have adjusted the contrasty of many image files of scans of very flat negatives without losing tonal values and without causing posterization. It is obviously important to work with 16 bit files (or change your 8 bit file to 16 bit) but expanding of compressing contrast should not reduce the number of total tones that you have unless you clip at the top or at at bottom.

Sandy

I'm not understanding his problem or your response. It's probably me.

If he's only got 255 levels, his scanner is set to output 8-bit tiff files, I assume.

If that's the case, then if his image is of low contrast, his file only has values from, say, 90-170. Stretching these out to 5-250 (in curves or levels or anything) will not give him the smooth transitions between each discrete value he would have if his image originally had the info over the entire 0-255 tonal scale. Does PS actually interpolate the values in-between and smooth the image's tonal range? It would seem that might soften what should otherwise be hard transitions that were in the original subject and make things look smeared.

But your answer makes me wonder what's wrong with my thinking: I'd have suggested he tell his scan software to output 16-bit tiffs so he still has a smooth tonal range even after stretching out a compressed one.

Where is my thinking flawed?

[Bob McCarthy]

[QUOTE=Wally;637951]I'm not understanding his problem or your response. It's probably me.

If he's only got 255 levels, his scanner is set to output 8-bit tiff files, I assume.

Does PS actually interpolate the values in-between and smooth the image's tonal range? [QUOTE]



PS does not interpolate, otherwise we'd have an infinite set of levels again.

But, I believe a levels adjustment just moves original data range into a new 0-255 value range and therefore reassigns the original values to the new ones.

Still the potential for harshness/funkyness is there.

bob

[sanking]

PS does not interpolate, otherwise we'd have an infinite set of levels again.

But, I believe a levels adjustment just moves original data range into a new 0-255 value range and therefore reassigns the original values to the new ones.

Still the potential for harshness/funkyness is there.

bob

But if you only have 255 tonal values to begin with, as with an 8 bit scan, you should have 255 tones whether you scanned a normal contrast negative in PS and left it as is, or scanned a flat negative in PS and expanded the contrast with curves (with no clipping of highlight or shadow tonal values), or if you scanned a high contrast negative and compressed the contrast with curves. In all three cases you should still have 255 tones.

It is of course fairly easy to cause posterization when applying tonal corrections to 8 bit files, which is why we should either scan in 16 bit, or change our 8 bit files to 16 bit before making any tonal corrections.

Sandy

[sanking]

For scenes of extreme contrast, DD-23 doesn't produce "miracles" either, while Divided Pyrocat does.

For sheet film however, I like DD-23 for scenes of low to moderate contrast. Because development takes place in both solutions, you can use DD-23 to control contrast, while still getting some "extra" compensation afforded by the fact that developer gets extinguished in the highlights. Unlike other approaches, you can develop first for the high values in Solution A, and then for the shadows in Solution B. It gives full film speed and excellent shadow separation.

After restoring my membership in View Camera the other day, the first thing I did was download and read Sandy's article on DD-23 and Diafine - written, I presume, before his work with Divided Pyrocat.

Ken,

At the time I wrote the article on two bath development for View Camera I was already experimenting with two bath Pyrocat but for several reasons I chose not to include tests with Pyrocat in the article.

I agree with you that divided D23 is a good developer for scenes of moderate contrast, and of course if you used development by inspection with IR light you can control the final contrast by repeating the procedure in Solutions A and B until you get what you want. Of course, you could do the same thing in two bath Pyrocat if for some reason you needed to do so.

Sandy

[Ken Lee]

So far, while using DD-23, I haven't tried returning the film to Solution A - I have simply kept it in Solution A longer or shorter, to taste.

But your post reminds me that we can do this with Divided Pyrocat too - which is something worth experimenting with.

[Bob McCarthy]

But if you only have 255 tonal values to begin with, as with an 8 bit scan, you should have 255 tones whether you scanned a normal contrast negative in PS and left it as is, or scanned a flat negative in PS and expanded the contrast with curves (with no clipping of highlight or shadow tonal values), or if you scanned a high contrast negative and compressed the contrast with curves. In all three cases you should still have 255 tones.

It is of course fairly easy to cause posterization when applying tonal corrections to 8 bit files, which is why we should either scan in 16 bit, or change our 8 bit files to 16 bit before making any tonal corrections.

Sandy

But 0 to 255 assumes a range from pure white to pure black. If you have a flat neg/pos with neither, you would have to have some quantity less than 256 tones.

When you adjust levels so you have a white and a black then you by defination have all 256 tones.
The tones are shifted to fill the range. I suspect this shifting is where we can see some funkiness.

bob

[Bob McCarthy]

or change our 8 bit files to 16 bit before making any tonal corrections.

Sandy

I don't believe this causes the desired effect.

When you change 8 bit data to 16, you still have 256 steps, but each step has 256 points all with the same value.

This is still 8 bit gradation. Capture at 16 bit to get the smoothness promised by 16 bit.

bob

[sanking]

I don't believe this causes the desired effect.

When you change 8 bit data to 16, you still have 256 steps, but each step has 256 points all with the same value.

This is still 8 bit gradation. Capture at 16 bit to get the smoothness promised by 16 bit.

bob


Yes, if you change an 8 bit file to 16 bit you still only have 256 gradations, but changing to 16 bit prevents farther loss of gradations that you get when making tonal adjustments with 8 bit files due top rounding up and down to the nearest tonal value number. And unless you are printing with a 16 bit driver you have to convert the file to 8 bit any way before printing.

I am not theorizing about the benefits of converting 8 bit files to 16 bits before doing any tonal manipulations. It is my primary work flow in processing scans of large sheet film with my Eversmart Pro, which only saves in 8 bit. I find that I can do a huge amount of tonal manipulation with these files if first I convert them to 16 bit, not so with 8 bit as they break down very quickly.

Sandy

[Bob McCarthy]

Yes, if you change an 8 bit file to 16 bit you still only have 256 gradations, but changing to 16 bit prevents farther loss of gradations that you get when making tonal adjustments with 8 bit files due top rounding up and down to the nearest tonal value number. And unless you are printing with a 16 bit driver you have to convert the file to 8 bit any way before printing.

I am not theorizing about the benefits of converting 8 bit files to 16 bits before doing any tonal manipulations. It is my primary work flow in processing scans of large sheet film with my Eversmart Pro, which only saves in 8 bit. I find that I can do a huge amount of tonal manipulation with these files if first I convert them to 16 bit, not so with 8 bit as they break down very quickly.

Sandy

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

[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 (http://www.kennethleegallery.com/html/tech/10.html) 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 :)

[Hugo Zhang]

Sandy,

I used this method first time yesterday and am impressed with it. I have used Rollo-Pyro all these years. One big question: the negatives from my third load, I used Jobo 3005, seemed not properly developed, all five sheets. I could barely see the images and I have to throw them away. Do you think the developers were exhausted then? I used 1:20 at both a and b and they are fresh.

Thanks,
Hugo

[sanking]

Sandy,

I used this method first time yesterday and am impressed with it. I have used Rollo-Pyro all these years. One big question: the negatives from my third load, I used Jobo 3005, seemed not properly developed, all five sheets. I could barely see the images and I have to throw them away. Do you think the developers were exhausted then? I used 1:20 at both a and b and they are fresh.

Thanks,
Hugo


Hugo,

I don't recommend re-using the solutions when you are rotary processing. Just dilute 1:20, use the minimum amount needed for the drum, and discard the solutions after one run.

Sandy

[nyletterpress]

The folks at Phototherm are setting up my FP-1 to do Pyrocat-HD according to Sandy's recommendations in the beginning of this thread. They are balking at using acetic acid as a stop bath, saying it will damage the check valves. Is there an alternative? Can I use water? and for how long. Many thanks for all the shared information!

[Tim Layton]

Sandy, several years have passed since this thread was posted, and I was wondering if you and others are still using Photoflo in Sol. A of Pyro-HD?


You can add the Photoflo at the beginning, as part of Solution A, or you could add it later, so long as you add it before draining and placing the film in Solution B. I always add it at the beginning, when I mix working Solution A.

Sandy

[Ken Lee]

See Two-Bath Development with Pyrocat:
A Simplified Methodology of Exposure and Development of Black & White Film for a Digital Work-Flow (http://www.pyrocat-hd.com/html/TwoBathPyrocat.html)

[Andrew O'Neill]

Sandy, several years have passed since this thread was posted, and I was wondering if you and others are still using Photoflo in Sol. A of Pyro-HD?

I do… actually I use Fuji's version, Dry-Well. I also give film a stop more exposure when 2-bath is anticipated.

[Andrew O'Neill]

Dug up a test I did comparing 2-bath and single bath. Film was HP5+. Done with BTZS tube. 1+10 for the two-bath. 6ml of A and B, each in their own cap with 60ml water. Temperature was held at 24C. Water presoak was given at same temperature for 3 minutes. Cap A got 5 drops of Drywell (Fuji's version of Photoflo). Film received vigorous agitation in both A and B, 5 minutes each.

For single bath (image on the left), BTZS tube as well, I gave N-7 development, which in my case is 4 minutes at 21C. No presoak was given.

Both negatives look very good. You can clearly see the 2-bath negative's highlight compensation. I should also add that I placed the darkest shadow under the chair on zone V. About a stop higher than normal.
These are straight scans. Only the black and white points were touched in the scanning software.

[LFLarry]

Ken, this is simply amazing. This could open up a lot of opportunities for my photography that simply didn't exist before. I have visited many historic places and simply walked away because I was there during the wrong light. Thank you for sharing this.

Also, in a new thread that I recently started you had suggested I check out the Divided Pyrocat development process and this is what lead me to this thread. I have a quick question for you. I mostly use my 4x5, but there are times when that just isn't possible and I use my little Nikon F100 and roll film. If I wanted to apply your metering technique as you described I was thinking I could do the following, but wanted to confirm my logic with you. Put the F100 in spot meter mode and meter for my shadows. Since that would be on zone V, dial in -1 exposure compensation and lock the exposure before focusing and taking the photo. That sound right to you?

Thanks

Larry




I hope a little more enthusiasm for Divided Pyrocat is not unwelcome. This post prompted me to perform an experiment: a photo made under mid-day Sun on a cloudless day - something I haven't done with a View Camera in decades, if ever.

With ordinary methods of exposure and development, adequate detail in both the shadows and high values would have been impossible. The shade areas would have been black and lifeless, or the sun-lit wall would have been white - but it was trivial with Divided Pyrocat.

I simply metered the shadow area and placed it on Zone IV. The high values fell way off the scale, but the 2-bath development process took care of that. The shadow area has full separation - a remarkable feat - as do the high values.

Sandy's suggestion of adding a few grams of Photo Flo to Solution A, has worked wonders: I now get perfectly even development.


http://www.kennethleegallery.com/images/forum/img007bdp.jpg
Massachusetts, 2010
Sinar P, 300mm Fujinon A
4x5 HP5+, Divided Pyrocat HD

[Ken Lee]

I mostly use my 4x5, but there are times when that just isn't possible and I use my little Nikon F100 and roll film. If I wanted to apply your metering technique as you described I was thinking I could do the following, but wanted to confirm my logic with you. Put the F100 in spot meter mode and meter for my shadows. Since that would be on zone V, dial in -1 exposure compensation and lock the exposure before focusing and taking the photo. That sound right to you?

Testing with 35mm film is a good idea: we can save on materials and more easily test extreme enlargements.

If we want a subject in the shadows to end up on Zone IV (as with the barn image above) then yes, we can place it there and let the high values fall where they may. This is one of the attractions of Divided Pyrocat: expose for the shadows, period.

That being said, a white horse in the shade ? a black cat in the shade ? Should they both be placed on Zone IV ? Not all "shadows" are the same.

As with all other film testing I have done, I found that using the published formula and developing times, Divided Pyrocat gives ~1/2 box speed: 50 for TMX and FP4+, 200 for TMY and HP5+, etc. We can split hairs and use 64 and 250, but the differences amount to a fraction of an f/stop, often beyond our ability to precisely meter a scene.

I should point out that I stopped using Divided Pyrocat because I couldn't always avoid uneven development. At that time, I developed sheet film in trays and did not want to give up development by inspection and adopt rotary processing. Since you use a JOBO, you may not have any problems.

Please share what you discover. I am happy to be proven wrong :rolleyes:

[LFLarry]

Hi Ken, thanks for your thoughtful reply and information.

I am planning to do some tests this weekend, assuming the weather provides the opportunity.

It is funny you mentioned the white and black subjects in the shade because I will have those exact scenarios in my future project, at least on occasion. Since the suggest with Divided Bath Pyrocat HD is to meter on the shadows, I will likely have to try a few different approaches to find something that is repeatable.

Either way, I will report back once I have some tests completed.

I am using a new Jobo CPP-3 with the Jobo Expert drums by the way, so we will see if the stains/uneven development are an issue or not under this scenario.

In years past, I have had some staining/streaking issues with Pyrocat HD in trays with 8x10 and 11x14 films and it got to the point that I abandoned it because I couldn't trust it, even though the good ones were some of my best work.

Thanks again.

-Larry



Testing with 35mm film is a good idea: we can save on materials and more easily test extreme enlargements.

If we want a subject in the shadows to end up on Zone IV (as with the barn image above) then yes, we can place it there and let the high values fall where they may. This is one of the attractions of Divided Pyrocat: expose for the shadows, period.

That being said, a white horse in the shade ? a black cat in the shade ? Should they both be placed on Zone IV ? Not all "shadows" are the same.

As with all other film testing I have done, I found that using the published formula and developing times, Divided Pyrocat gives ~1/2 box speed: 50 for TMX and FP4+, 200 for TMY and HP5+, etc. We can split hairs and use 64 and 250, but the differences amount to a fraction of an f/stop, often beyond our ability to precisely meter a scene.

I should point out that I stopped using Divided Pyrocat because I couldn't always avoid uneven development. At that time, I developed sheet film in trays and did not want to give up development by inspection and adopt rotary processing. Since you use a JOBO, you may not have any problems.

Please share what you discover. I am happy to be proven wrong :rolleyes:

[Steve Goldstein]

Seeing this thread come back to life prompted me to go back and re-read Sandy's original article. He mentioned he used this method for scanning. Have any of you recent posters (Ken, Larry, and less recently Andrew) wet-printed from negatives processed with two-bath Pyrocat? My naive thought is that it should be feasible if the negatives are processed to a CI of around 0.58, but in my case a little knowledge may be a very dangerous thing indeed!

Thanks for any insights.

[Ken Lee]

Seeing this thread come back to life prompted me to go back and re-read Sandy's original article. He mentioned he used this method for scanning. Have any of you recent posters (Ken, Larry, and less recently Andrew) wet-printed from negatives processed with two-bath Pyrocat? My naive thought is that it should be feasible if the negatives are processed to a CI of around 0.58, but in my case a little knowledge may be a very dangerous thing indeed!

My usage of Divided Pyrocat was only for a scanning workflow.

In the recent thread on developers Finest Grain 120 Film & Developer Combo Currently Available (https://www.largeformatphotography.info/forum/showthread.php?159812-Finest-Grain-120-Film-amp-Developer-Combo-Currently-Available) (which prompted Larry to resurrect this thread) I made the following suggestion:


"...keep in mind that with Divided Pyrocat, all images are automatically developed to the same contrast level. For a scanning workflow, that's not a problem since we can always add contrast in an editing tool. For a darkroom workflow you may need to make a few adjustments to get a contrast level which works for your workflow of light source/paper/developer etc."

[Tin Can]

I also reread Divided Pyrocat to the end

I scan most negs for a record, but primarily contact print above 4x5 and enlarge smaller

I MAY try Divided Pyro on roll film




My usage of Divided Pyrocat was only for a scanning workflow.

In the recent thread on developers which prompted Larry to resurrect this older thread (Finest Grain 120 Film & Developer Combo Currently Available (https://www.largeformatphotography.info/forum/showthread.php?159812-Finest-Grain-120-Film-amp-Developer-Combo-Currently-Available)) I recommended as follows:


"...keep in mind that with Divided Pyrocat, all images are automatically developed to the same contrast level. For a scanning workflow, that's not a problem since we can always add contrast in an editing tool. For a darkroom workflow you may need to make a few adjustments to get a contrast level which works for your workflow of light source/paper/developer etc."

[Steve Goldstein]

Thank you, Ken, that's an important point I'd missed when re-reading both threads.

[sanking]

I appreciate Ken's reference to my work with 120 Acros film and to the article on two-bath development that can currently be accessed at https://www.pyrocathd.5x4.co.uk/.

Since 2015 I have used the two-bath procedure with Pyrocat-HCD for the great majority of my development of both medium format and large format film, which at this time is only done for a hybrid workflow with scanning and digital processing and the information in that article should be considered my last stage of experimentation. It is possible to adjust the strength of the formula, and/or temperature of development, to develop for specific conditions of SBR to control contrast for optical printing in the darkroom, and I am aware of at least one person who has a very refined workflow for silver printing with that approach. However, the beauty of the two-bath method has always been for me in the simplicity of just exposing for film speed and desired shadow density and allow development to do the rest. Or should I say I do the rest with image controls in PS.

In the past I became fairly proficient in the use of the BTZS approach to tailor exposure and development, but this involved a lot of record keeping in the field, and subsequent sorting of the film for development. When I converted to scanning and printing digitally the two-bath procedure made a lot more sense to me, and with the two-bath system micro-contrast with edge effects is optimized for this developer compared to any other type of development, including minimal agitation. So while Acros was my favorite film I found that two-bath development was capable of similar results with other ISO 100 T-grain films, including TMax-100 and Delta 100.

Sandy

[Jim Noel]

Is there no remedy for the build up of Photo Flo?

Sandy

Sorry for the delay. I have not been paying attention to this thread for quite some time.
LFN does not coat the reels, and it does not become a catalyst as does PhotoFlo
Eliminating PF from our lab completely eliminated all problems with over-developed film edges .

[Jim Noel]

I have many stained reels and tanks that work exactly like my many unstained reels and tanks. I wash my tanks and reels in hot water after each use, and have never seen any build-up of anything. Maybe I'm just lucky!

Washing in hot water eliminates the PF