Why use divided development?

[swmcl]

When you could be using 'contrastwise film bleaching' ...

Contrastwise film bleaching as explained by David Kachel et. al. involves bleaching the film after exposure and before development. It is achieved by using a very weak dilution of potassium ferricyanide which sounds highly toxic but I believe is not nearly so.

One simply immerses the film into the bleach with full agitation for a number of minutes. The result is a film response curve that is laid down to achieve a lower contrast ratio. I believe the process is entirely proportional to the amount of exposure. A slight loss of film speed should be countered during exposure.

As I understand it, a CI of between 0.4 and 0.5 is easily achieved. Thus a photograph with a more extreme SBR range can be accommodated for traditional printing methods with this process.

Similar outcomes can be had with divided developer techniques. Of particular interest is the Divided Pyrocat process which, by all accounts, produces wonderful results. Simply using Diafine is another well-known divided developer.

The difference is that the concentration of the Pyrocat in the Divided Pyrocat process is commonly 15:300 which is about 5 times what others use in a rotational process at 3:300. This makes the Divided Pyrocat process pretty expensive.

The other difference is also that a divided process is strictly a 'stand' process which is not possible with daylight tanks unless you want to completely fill a 3005 or 3006 for example !! More than a litre at 15:300 is extreme.

I suspect the answer to this question might be something to do with the range of results. For example, perhaps the contrastwise bleaching can't produce N-5 development as well as the Divided Pyrocat process ??

Cheers,

Steve

[David Karp]

I have used Diafine, Divided D-76, and Barry Thornton's variant of Divided D-23. The divided development process helps to ensure that you don't blow out the highlights in high contrast scenes, while at the same time preserving shadow detail.

Divided development is not strictly a stand process. I have used it with hangers and tanks, a slosher, and in JOBO Expert Drums. Anchell and Troop recommend using rotary development with divided developers.

[Greg]

Following advice from an article in VIEWCAMERA magazine, use divided development with Diafine to produce negatives (as David stated not to blow out the highlights) that are easily scanned to produce digital negatives for Pt/Pl printing. Have been getting excellent results by just reading Zone II to determine my exposure. FYI: For real extreme ranges of light, tried shooting digitally with HDR combining the exposures and making digital negatives to print with... resulting Pt/Pl prints were very artificial looking and I no longer go down that road.

[sanking]

Steve,

If you have not already seen it, please look at the article on divided Pyrocat that I added to the PyrocatHD web site a couple of years ago. http://pyrocat-hd.com/html/TwoBathPyrocat.html

Bleaching and re-development can be used to reduce (or increase) the density range of film negatives. The problem with this method is that if anything goes wrong you lose your negative.

Divided development is, IMO, the best method to use for scenes of very high contrast, and also works nicely for all scenes where the intention is to scan and process the files digitally.

Divided development is not done with stand development, at least not with Pyrocat. In fact, with sheet film the best method I found was rotary development in drums, with continuous agitation. With roll film I developed with the film on stainless steel reels, in tanks, with intermittent agitation.

Sandy

[Steve Sherman]

Divided Pyrocat for me did not provide the necessary negative density to directly print to the Silver wet process. I have no experience with the negative bleaching process.

I can however speak to regular success with Extreme Minimal Agitation and the Semi-Stand technique in controlling contrast ranges requiring N - 5 as well as N - 6 lighting situations.

I have come to learn controlling the extremes of Contrast in either direction yield the most dramatic adjacency effects over continuous agitation. Further, to realize success with N - 5 or 6 is an ever so delicate balance of developer exhaustion relative to agitation frequency and the length of time one is able to exploit this phenomenon. I do believe the technique I have refined can control via the wet process extremes of small or huge amounts of Contrast that few working film photographers can lay claim too.

[swmcl]

OK so I look to be wrong about an absolute need to use a stand development but I trust the requirement to use 5 times the concentration of developer (part A of Pyrocat-HD) still stands ?

I use Pyrocat-HD at 5-5-300 with FP4 and may need to back it off a little with HP5 as it is a little too reactive at 5-5-300 so I am inclined to hear Steve Sherman saying it didn't achieve negative densities. I do also have Diafine.

Can the Pyrocat-HD part A be re-used like Diafine ? Probably not (even during the one processing session of a few ours) as it oxidises ?

Steve what equipment do you use for Extreme Minimal Agitation ? I'm using 4x5 and 5x7 sheets.

Cheers,

[Doremus Scudder]

When you could be using 'contrastwise film bleaching' ...

Contrastwise film bleaching as explained by David Kachel et. al. involves bleaching the film after exposure and before development. It is achieved by using a very weak dilution of potassium ferricyanide which sounds highly toxic but I believe is not nearly so. ... I suspect the answer to this question might be something to do with the range of results. For example, perhaps the contrastwise bleaching can't produce N-5 development as well as the Divided Pyrocat process ??

Cheers,

Steve

I've been using the SLIMT (Selective Latent Image Manipulation Techniques) described by David Kachel for years for extreme contractions.

This is not bleach/redevelop (which I also use from time-to-time to increase contrast), rather a treatment of the exposed negative in a very dilute ferricyanide/bromide solution immediately prior to development. I find that I actually retain more effective film speed with extreme contractions than by using changes in time and/or dilution. I can easily go down to N-5 if needed, though I rarely have to. Since the latent image bleaching occurs proportionally, it is the highlights that are most bleached, reducing contrast there most, and retaining more separation in the low values.

The real trick to this technique is calibrating it. I'd start with trying to find a good N-2. Choose an appropriate subject and make a slew of negatives; at least 4, but 6 would be better if you're starting from scratch. Then extrapolate from Kachel's articles or whatever to find a starting point for the SLIMT bath (I'm using about 3.5 min in a 0.01% ferricyanide solution for TMY in PMK). After the ferri treatment, transfer the negative to the developer and develop nomally. Measure densities and/or print on grade 2 and then refine your SLIMT time. There will be different times and dilutions (I use from 0.005% to 0.02%) for different contractions, and film/developer combination. Most of my SLIMTs are done with "Normal" developing time, but for extreme contractions I'll use them in conjunction with reduced development, e.g., N-1 development time plus SLIMT to get N-4.

SLIMTs coupled with a reduced agitation regime (although I don't reduce agitation anything like Steve Sherman does) gives me easily printable negs with lots of edge effects.

Best,

Doremus

[Steve Sherman]

OK so I look to be wrong about an absolute need to use a stand development but I trust the requirement to use 5 times the concentration of developer (part A of Pyrocat-HD) still stands ?

I use Pyrocat-HD at 5-5-300 with FP4 and may need to back it off a little with HP5 as it is a little too reactive at 5-5-300 so I am inclined to hear Steve Sherman saying it didn't achieve negative densities. I do also have Diafine.

Can the Pyrocat-HD part A be re-used like Diafine ? Probably not (even during the one processing session of a few ours) as it oxidises ?

Steve what equipment do you use for Extreme Minimal Agitation ? I'm using 4x5 and 5x7 sheets.

Cheers,

I use 4x5 film for testing, personal shooting films are 5x7 and 7x17 done in vertical free standing tubes, one sheet at time.
Pyrocat is so inexpensive, even though Sandy King says it can be reused a second time I do not. Film processing for me is very exact, especially given the lighting conditions I find myself in so one less variable to me is a big plus, and that second run of film thru developer would amount to a variable I don't want to deal with.

[sanking]

Do not confuse divided development with stand and other minimal agitation methods. Both methods work well, but each is designed to address a specific need and the dilutions and techniques required are quite different for the two mehtods.

OK so I look to be wrong about an absolute need to use a stand development but I trust the requirement to use 5 times the concentration of developer (part A of Pyrocat-HD) still stands ?

A 1+20 dilution of stock concentrations A and B are about normal for an average CI of about .55, but it varies quite a bit by emulsion, as you can see in the CI charts for different films that accompany the article at the Pyrocat web site.


Can the Pyrocat-HD part A be re-used like Diafine ? Probably not (even during the one processing session of a few ours) as it oxidises ?

This depends on method of development. If you are developing two rolls of 120 film in a tank with 1000 ml of a 1+20 working solution you can re-use the solution 4-5 times if all of the development is done the same day, or in a 6-8 hour period. However, if you are using a minimum of working solution for rotary development in a tube (say 75 ml for a sheet of 4X5 film), the solutions should be used only once and discarded.

There may be minor variations in CI with re-use of the working solutions, but please remember that my recommendation for divided development is for a work flow where the negatives will be scanned and worked in PS, not for a work flow in which the negatives are printed directly. With scanning low CI is desierable, and minor variations in contrast are quite acceptable when the image file will be processed for final contrast.

The advantage of divided development, IMO, as I express in the article, are as follows.

This article on the use of Pyrocat as a two-bath developer is directed primarily to those photographers who expose and develop film for scanning, not for those who print optically with analog methods. Pyrocat, when used as two bath developers, is capable of extreme compensation, and no loss of film speed. Regardless of the contrast of the scene you simply expose for the deepest shadows where you want texture or detail, then develop the film in two-bath Pyrocat. The result should be a negative with good shadow detail, a linear straight-line curve, and highlights that are well within limits for scanning with a consumer type scanner like the EPSON V700. This is about as close to a “silver bullet” in film developing as I have found.

Compared to the use of Zone and BTZS type methodology there are several advantages of two-bath Pyrocat for the scanning work-flow:

1. Field work is simplified because there is no need for note taking to identify individual sheets for SBR or N type development, as in BTZS and Zone methodology. The only requirement is that the negative be correctly exposed for the shadow values where texture and detail is desired.

2. All negatives of the same film type can be developed together for the same time and temperature. In fact, in most cases even different films can be developed together.

3. The negatives will develop to a fairly low average gradient, which reduces grain and optimizes sharpness. The appearance of grain is finer because grain is dependent on contrast and density; the higher the contrast and density, the more pronounced is the grain. And, developing to a lower contrast optimizes resolution because it minimizes halation and irradiation. Photographers who use 35mm and medium format are well aware of the importance of developing to a low contrast to minimize grain and enhance sharpness.

4. Negatives developed to a low average gradient scan very well, even with consumer flatbed scanners.





Sandy

[tgtaylor]

I've read, but have not tried, that uranium toner will increase a negatives density.

Thomas

[jnantz]

hi steve
i use divided caffenol and dektol
because it lets me use a variety of films
in old cameras that have no exposure control ... without issue.

[Drew Wiley]

I'm not up to date on this. I got good results with divided D23 back when thick emulsion sheet films were routine, but never liked how this method lowered the
acutance. Now when I want to capture a lot of luminance range in the subject, I just use a more appropriate film. I've earned my right to be lazy.

[sanking]

I'm not up to date on this. I got good results with divided D23 back when thick emulsion sheet films were routine, but never liked how this method lowered the
acutance. Now when I want to capture a lot of luminance range in the subject, I just use a more appropriate film. I've earned my right to be lazy.


Divided D23 is not a true divided developer of the Diafine/Pyrocat type in that some development begins in Solution A. I also found divided D23 it to be a low acutance developer, quite unlike Diafine and Pyrocat, which have extremely high acutance.

There are several strategies that can be used with film to capture an extremely long range of subject luminance values, but true two-bath developers like Diafine and Pyrocat have the unique ability to do this without having to take extensive exposure and subject brightness range notes. You just expose for the shadows, the method automatically prevents development beyond a relatively low CI which is ideal for scanning, but may or may not be ideal for printing directly from the negative.

Sandy

[swmcl]

I would like to ask a question...

The divided developer process is a develop-to-exhaustion process is it not ? The process relies on the film (or paper) absorbing one of the chemicals such that when placed into the second bath there is a reaction but it will exhaust itself eventually.

Yes ?

[sanking]

I would like to ask a question...

The divided developer process is a develop-to-exhaustion process is it not ? The process relies on the film (or paper) absorbing one of the chemicals such that when placed into the second bath there is a reaction but it will exhaust itself eventually.

Yes ?

Yes, the film absorbs the reducer component of the developer in Solution A, then when the film is transferred to Solution B development takes place very rapidly. In fact, much of the develoment is virtually instaneouos as the reducer is exhausted almost instantly, as you see for example in working with developing out pt/pd. The sudden exhaustions is the mechanism that causes the creation of very pronounced adjacency effects.

Sandy

[swmcl]

Any process that is develop-to-exhaustion must then introduce a shoulder to the CI curve. The shoulder would be more pronounced for a thin emulsion type film simply because the film just cannot absorb very much of the first chemical.

It can never be that one develops over a longer period of time to get a proportionately increased density because the chemicals have been exhausted. Without looking at the instructions for Diafine I think they do say or imply that time and temperature are somewhat irrelevant for this reason IIRC.

Thus the more dense areas are compressed and the film just cannot distinguish between various dense values.

In this scenario, a highly exposed high-key negative would have limitations on being able to separate the high tones.

Yes ?

[swmcl]

Just to answer my own post ... some text from the Diafine and Accufine instruction sheet ...

Diafine may be used within a temperature range
of 70 to 85°F with a minimum time of 3 minutes
in each solution. Increased developing times will
have no practical effect on the results. It is rec-
ommended that you do not exceed 5 minutes in
either solution.

I have copied and pasted from the document directly - please excuse the formatting.

[sanking]

Any process that is develop-to-exhaustion must then introduce a shoulder to the CI curve. The shoulder would be more pronounced for a thin emulsion type film simply because the film just cannot absorb very much of the first chemical.

It can never be that one develops over a longer period of time to get a proportionately increased density because the chemicals have been exhausted. Without looking at the instructions for Diafine I think they do say or imply that time and temperature are somewhat irrelevant for this reason IIRC.

Thus the more dense areas are compressed and the film just cannot distinguish between various dense values.

In this scenario, a highly exposed high-key negative would have limitations on being able to separate the high tones.

Yes ?[/QUOTE]


Some of your points/questions would require empirical data to address. In terms of highlight compression, I have never found that to be a problem with divided development with either Diafine or Pyrocat. Actual curves plotted from divided development are in fact quite linear, with very little toe and/or shoulder. You can see one family of curves in the article, which is a real family of curves from film developed in divided Pyrocat.

Sandy

[sanking]

Just to answer my own post ... some text from the Diafine and Accufine instruction sheet ...

Diafine may be used within a temperature range
of 70 to 85°F with a minimum time of 3 minutes
in each solution. Increased developing times will
have no practical effect on the results. It is rec-
ommended that you do not exceed 5 minutes in
either solution.

I have copied and pasted from the document directly - please excuse the formatting.

The Diafine instructions are what they are, but don't expect general directions like this to apply equally to all films. Emulsions are very different in the way they are able to absorb reducer, and the Diafine instructions provide no solution to address this issue in the manner of mixing and dilutions.

Sandy

[jnantz]

I would like to ask a question...

The divided developer process is a develop-to-exhaustion process is it not ? The process relies on the film (or paper) absorbing one of the chemicals such that when placed into the second bath there is a reaction but it will exhaust itself eventually.

Yes ?

ive developed several "runs" of film using 1L of chemistry
and the sumatranol .. i have 3-4L mixed, that i have used for
4 - 5 months a a time withott mixing new

YMMV

[swmcl]

In my experience Diafine always produced flat negatives. It is in fact one of the reasons I switched all those years ago to using Pyrocat-HD. I wont be surprised to find that any other divided development process will reveal the same issues with density that Diafine does. After all, how many people tell of using Diafine to 'rescue' an over-exposed negative ?!

The other reasons for using Pyrocat-HD for me was the long shelf life, the cheap costs and the staining / tanning effects. If a divided process is using concentrations at 5 times the usual then I will not be able to use it I'm afraid for the cost factor.

However, it has been a useful discussion.

[Michael R]

swmcl,

If I may interject, some time ago I did a fairly extensive study of divided (true divided and not true divided) developers. I can support what Sandy King has said regarding curve shape. Rather than introduce an earlier, more gradual shoulder (which is what "compensating" development tends to do), this process tends to give a long, straight line with little shoulder or toe, high emulsion speed, and an essentially normal gradient.

Whether or not the final print appears "flat" or not has to do with tone reproduction, and the negative is only part of the total system so it can't be considered in isolation without knowing more about the subject, scanning vs darkroom printing (and the type of paper).

[Steven Ruttenberg]

To resurrect this post, I am experimenting with SLIMT plus 2-bath Pyrocat. First test I must have done something wrong. It worked but didn't. Very uneven development and thin negatives however, I n the a r was of the negative it appears to work, it worked well.

I don't see a reason it shouldn't work. I am looking for a way to get a very extreme zonal range with detail such that I could have a 15 stop difference or more between my darkest shadows and brightest highlights. Trying to get the best of both worlds in one shot. Maybe it won't work ever, but never got anywhere without a trip to get there.

Has anyone ever tried this? Or similar? I assume SLIMT would work in a regular Pyrocat HD development process (A+B) if so, should work as divided. Unless the chemicals are incompatible.

[Pere Casals]

To resurrect this post, I am experimenting with SLIMT plus 2-bath Pyrocat. First test I must have done something wrong. It worked but didn't. Very uneven development and thin negatives however, I n the a r was of the negative it appears to work, it worked well.

I don't see a reason it shouldn't work. I am looking for a way to get a very extreme zonal range with detail such that I could have a 15 stop difference or more between my darkest shadows and brightest highlights. Trying to get the best of both worlds in one shot. Maybe it won't work ever, but never got anywhere without a trip to get there.

Has anyone ever tried this? Or similar? I assume SLIMT would work in a regular Pyrocat HD development process (A+B) if so, should work as divided. Unless the chemicals are incompatible.

Steven, if you want to go to advanced development techniques I'd read:

184446

... to have the right weapons.

While Photochemistry is a complicated discipline, that book contains selected knowledge for those wanting to experiment beyond regular procedures.

Film can do amazing things, in this shot I darkened the landscape for aesthetics, it was not as underexposed as it looks, but see the sun disc...

https://c1.staticflickr.com/9/8613/16197872534_897035fe00_b.jpg

I think the solar disc is darker than the crown because "Solarization". Beyond the saturation limit sensitivity has a reversed slope, because this the solar crown is visible, I guess.

[Steven Ruttenberg]

Nice image. i am reading and will check out the book you reference. I like to think there is always something more we can achieve than what has already been done. Especially if you cannot put your finger on exactly what it is you hope to achieve. The fact that you have the idea is enough and when you realize what you are after you may find it is 180 degrees from where you thought you wanted to be.

I need to make about 1/2 to a dozen of the exact same image to do the experiments with SLIMT and 2-bath. I think part of what I ran into was a set of severely underexposed negatives. Had a red#25,f/16, and a polarizer. I may have miscalculated my exposure times. The brighter objects are okay, the darker are essentially unexposed.

[mrred]

I spent a couple of years building a pyro developer specifically to do divided development. I wanted maximum activity, good contrast, fine grain and longer lasting in solution. What I have works for me with results beyond what I expected. My drive was from the fact that there was nothing out there that I liked.

My A solution will last well over 6 months (catechol / metal based). My B is lye based from a stock 10% solution. The final is a one shot.

With all of this, I would never resort to a bleach as a matter of proceedure. If you keep building negs you don't like, I would rather fix that instead.

184451

[Steven Ruttenberg]

Just experimenting at this point to see what is possible or not. Main goal is to develop a method gives me what I want regardless of process.

[mrred]

Divided for me, with a tanning and staining agent, gives me negs that are the most perfect I have ever made. I've been shooting since the mid-70s.

Bleaches to me seem like fixing a problem with a crowbar.

Another advantage not mentioned here with divided is it is very efficient when developing large format in mostly empty tanks. Very little goes down the drain.

[Pere Casals]

divided development.
184451

In theory divided development is intended for compensation, I don't see that effect in your sample image, I'd ask you why and how you use it.

[mrred]

Here is a better example for what you said. It uses hypercat diivided, before I had worked out my own formula.

184458

This was a super bright sunny day and I shot at least 1 stop over, but developed normally. The highlights and details look remarkable.

As far as my choice for divided is more than just the compensation. For example I really don't like diafine beceause of the pothole grain and the speed changes in most films. With Catechol based developers you get the fine grain, tanning and compensation. I use my dived beceause it just works better.

[Steven Ruttenberg]

Looks good. I like the blower!

[mrred]

I only got to take home the image. :(

[Jim Noel]

Too many errors and unfounded statements in the Cookbook. If you really want to learn about all elements of exposure and development and how to control ithem, get a copy of Richard Henry's "Controls in Black & White Photography". He tested every statement he made.

[mrred]

I wouldn't look at the cookbook as a gospel testament. It's more like a running history and documentation. As such, it's a great reference. You should just know what it is.

[Andrew O'Neill]

I have used David Kachel's bleach and redevelopment method. It can work very well, infact, it's the best out there for extreme contractions...but every film reacts differently. The best film ever for this process is TMY-2... a downside as this film is too expensive for me today. If you are not careful, the process can get away from you really easily, and one must always shoot a backup, just in case. Then I started using Pyrocat-HD at the turn of the century, and never looked back. I only use Divided Pyrocat-HD development when I need big contractions. Works very well for scanning and digitised negs.

[Steven Ruttenberg]

So far, the bleach works pretty well. I am hoping to marry the two, ie bleach plus 2-bath. I also need options for both traditional printing and digital printing. I really think the film has more in the way of exposure range than we think, even today. Since bleach reacts only on the highlights (mostly) and the 2-bath but in a different manner there is a potential for possibly something to be gained. Maybe not. I am also very interested in the pull process using the bleach method Kachel discusses, but the chemical is a bit nasty. I also worry about whacking the shadow detail if I do a pull process.

I wonder if it is possible to contract and pull an image using the two different bleach baths. And yes, take two images of everything that you plan to do bleach on and even 2-bath.

I think this is part of what I am trying to achieve. Expose for deepest shadows to zone v if you will, maybe even 6, then contract the scene and pull it at the same time. I am sure this has been done in some form. I just like to experiment.

I will check out both books before buying. Anyone have a pdf copy of either or both?

[interneg]

Too many errors and unfounded statements in the Cookbook. If you really want to learn about all elements of exposure and development and how to control ithem, get a copy of Richard Henry's "Controls in Black & White Photography". He tested every statement he made.

Would strongly second this statement!

[Pere Casals]

Too many errors and unfounded statements in the Cookbook.

Jim, is there any example ?

Of course Controls in Black-And-White Photography is a good recommendation, but as a reader of the cookbook I'd like to know if there is any clear mistake there...

[Jim Noel]

Jim, is there any example ?

Of course Controls in Black-And-White Photography is a good recommendation, but as a reader of the cookbook I'd like to know if there is any clear mistake there...

When I purchased the book years ago, I read it cover to cover and marked significant errors. I found so many, I threw the book in the trash, thus no examples at hand.

[Andrew O'Neill]

It's true about the errors in the cook book. A friend of mine noted all the mistakes he could find, sent them in to the author, but fell on deaf ears. It still is a damn good reference book that I have used over the years.

[Steven Ruttenberg]

Would be nice if there was some sort of errata sheet. I would hate to be following some advice and jack up a negative I can't recreate. So far, all the ones I screw up, I can go back and redo.

[mrred]

Ultimately, opinions get treated as fact, over time. Like all things on Facebook, peaple sputter out things they know nothing about without thinking. When you point out the error in their words a lynch mob will appear. You are now the antichrist. Lightning bolts from the sky have yet to appear.... :)

When I started to ask questions about doing reversals 10 years ago, I got a lot of opinions from people who could not answer why. So I just looked around as much as I could and did experiments and proved what did and didnot work. I figured out what was actually happening and developed my own process.....and could answer what I did and why.

So I would take the cookbook in hand and use it as a reference. Do tests and see what actually works and go from there. Most of it is good. How many revs is that book up to now? It does get corrected.

[Andrew O'Neill]

When I started to ask questions about doing reversals 10 years ago, I got a lot of opinions from people who could not answer why. So I just looked around as much as I could and did experiments and proved what did and didnot work. I figured out what was actually happening and developed my own process.....and could answer what I did and why.

The best way to learn anything.

[Steven Ruttenberg]

Learn by doing. It is the only way to do it.

[Pere Casals]

When I purchased the book years ago, I read it cover to cover and marked significant errors.


It's true about the errors in the cook book.


Would be nice if there was some sort of errata sheet.

There is an errata sheet with the corrections:

http://anchellworkshops.com/books/errata/fdc_errata.pdf

so no problem...