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rdenney
19-Nov-2010, 14:15
I've been doing some serious exploring. I have acquired the 2551 tank and a 2509N reel that I was asking about a couple of weeks ago, and now I'm starting to consider processing techniques. If my intentions were limited to my previous experience, I would look for FP4+ and soup in HC110 dilution B. But one of the things pulling me back to the notion of souping my own black and white is some of the ultra-wide dynamic range being achieved by Sandy King, Ken Lee, Jay DeFehr, and others.

The key to achieving that wide range seems to be to use something like Pyrocat MC in a two-bath process, where solution A soaks the film with developer (the degree of soaking which controls the degree of development), and solution B causes the development action and develops to completion, with the highlights exhausting the absorbed solution A more quickly which provides the compensation. And the chemicals seem to have enormous shelf life. That development-to-exhaustion approach seems pretty compatible with this tank and reel, and the longevity to my very occasional use.

But my question has to do with suitability for subjects. I'm assuming that the compensation action puts a wide toe on the highlights, so that the middle and lower values are pretty conventional in terms of mapping densities to zones, but the highlights, instead of blocking up, are spread more narrowly over a range of usable densities. Am I understanding that correctly? It seems to me that one would use this approach by measuring the shadows and placing the exposure for Zone III or IV and then let the highlights fall where they may, adjusting contrast as needed after scanning. If that is the case, then this seems a pretty good general-purpose approach for a wide-range of subjects, even those that are flat, assuming the use of Photoshop.

Will this process pair up with any good, general-purpose medium-speed film like FP4+?

Rick "making sure he is understanding what he reads" Denney

Bruce Watson
20-Nov-2010, 07:58
Mostly. The toe is the shadow region (low density part of the negative). The shape of the toe is largely set by the film manufacturer. Development mostly effects the highlights (higher density parts of the negative). What you seem to be after is called a shoulder. If I interpret what you wrote correctly, you seem to want more of an S-curve rather than a linear response from your exposures.

Sandy King wrote a nice article in View Camera a few years back about using divided developers for scanning. You might want to dig around and find a copy.

Personally I take a somewhat different approach. I develop TMY-2 in XTOL. I develop to a Zone VIII density of around 1.0. This would be considered maybe a one stop "pull" by old school darkroom workers (like I used to be) and would be somewhat difficult to print in the darkroom. This combination is more linear than S-curve.

Either method comes down to "expose for the shadows and let the highlights fall where they may."

rdenney
20-Nov-2010, 09:55
Mostly. The toe is the shadow region (low density part of the negative). The shape of the toe is largely set by the film manufacturer. Development mostly effects the highlights (higher density parts of the negative). What you seem to be after is called a shoulder. If I interpret what you wrote correctly, you seem to want more of an S-curve rather than a linear response from your exposures.

Okay, I missed the terminology--shoulder is what I meant.

And it's not necessarily something I want, though I'm not opposed to it. I am trying to understand what it does. If the response is linear, then the S-curve will have to be applied in Photoshop. Keeping it linear would force clipping, unless the middle values are left with relatively little separation. If I set the exposure based on a shadow measured and placed at Zone III, a middle highlight that might normally fall on Zone VI or VII might show density more like Zone V if the response is linear and 20 stops of scenery brightness are compressed into 10 zones of print tonality. I was assuming that zones and stops would approximately align in the middle values, but perhaps not.

But in the examples I've seen, the tonal separation in the highlights is definitely there, but more subtle than the separation in the middle values, suggesting that somewhere along the line, the response curve acquires an S shape. Maybe this is done in Photoshop.

I knew of Sandy's article but do not have that issue and I can't find any online copy of it. I have read much of what Sandy has written on the Pyrocat website and on various posts here.

Mostly what I want to know is whether the approach I've outlined works for general-purpose films and general-purpose subjects, with the proviso that contrast can be increased on the computer by a greater amount than in a darkroom. And I want to know if it works with middle-of-the-road films that are cheap and available, like FP4.

Rick "not wanting to build basic technique around what most consider a specialized approach" Denney

Jay DeFehr
20-Nov-2010, 10:50
Hi Rick,

While I'm flattered to be mentioned alongside Sandy and Ken, my work has little in common with theirs. I know almost nothing about scanning, and make my negatives to print in my darkroom. I scan some of them for archiving purposes, and for web posting, but most of my scans fail to meet even that modest standard. And so, I'm as interested in seeing the responses to this thread as you are!

Bruce Watson
20-Nov-2010, 12:38
If the response is linear, then the S-curve will have to be applied in Photoshop. Keeping it linear would force clipping,...

By what? What's clipping? If the scanner is clipping, it's typically because the operator set the software to clip. A not unreasonable thing to do in some cases. But it's not required, nor inherent in developing film. Most scanners can see through densities over 3.0, and if your B&W film is that dense, you're likely going to find other interesting artifacts from the abuse.

In my experience, nothing you can do to the film in processing can cause any kind of clipping in a scanning workflow.


unless the middle values are left with relatively little separation. If I set the exposure based on a shadow measured and placed at Zone III, a middle highlight that might normally fall on Zone VI or VII might show density more like Zone V if the response is linear and 20 stops of scenery brightness are compressed into 10 zones of print tonality.

This is somewhat of a non sequitur.

In darkroom printing, the negative is an intermediary. Its function, among other things, is to translate the subject brightness range (SBR) into a density range that closely matches the capabilities of the photo paper. Accomplishing this, accurately and precisely, is why Archer and Adams invented the Zone System. The point is to make it relatively easy to make a print from a given negative that meets the vision of the photographer.

In digital, this paradigm is a moot point. The negative doesn't have that duty -- there's nothing to match to. In digital, all we want is a negative that's relatively easy to scan. That typically means that a negative optimized for scanning has a smaller density range than a negative optimized for the wet darkroom.

But the important point here is that the negative has no duty to match its density range to the print paper. That duty falls to the scanner, not the negative. And the scanner can typically read through whatever density range you can through at it. This is because scanners are almost always optimized for color transparencies. And trannies have a density range that is wall beyond the range for B&W negatives.

So what happens is, the scanner reads the film and translates the density range it sees, be it a range of 0.3 or 3.0, into a digital range of 0-255 (if 8 bit), or 0-65535 (if 16 bit), etc. This digital range is an *exact fit*, by definition, to the printing substrate, whatever it may be.

I'm just sayin' that it's a mistake to think of the digital workflow in terms of the darkroom workflow. They are not analogous.


...in the examples I've seen, the tonal separation in the highlights is definitely there, but more subtle than the separation in the middle values, suggesting that somewhere along the line, the response curve acquires an S shape. Maybe this is done in Photoshop.

Typically film is scanned to capture all that is there. This results in a "flat" capture. Using a photo editor like photoshop, one can clip the shadows and highlights as appropriate, and apply whatever curves one wants to increase/decrease contrast, to bump up or down contrast in a given area of tones, etc.


Mostly what I want to know is whether the approach I've outlined works for general-purpose films and general-purpose subjects...

Yep. It does. As they say, there are many paths to the waterfall.

Jay DeFehr
20-Nov-2010, 14:47
In digital, all we want is a negative that's relatively easy to scan. That typically means that a negative optimized for scanning has a smaller density range than a negative optimized for the wet darkroom....Most scanners can see through densities over 3.0, and if your B&W film is that dense, you're likely going to find other interesting artifacts from the abuse......This is because scanners are almost always optimized for color transparencies. And trannies have a density range that is wall beyond the range for B&W negatives........In my experience, nothing you can do to the film in processing can cause any kind of clipping in a scanning workflow.


Bruce,

I hope you'll be patient with a very novice scanner, and explain the apparent discrepancies above. If scanners are optimized for density ranges beyond those typical for B&W negatives, why would a negative optimized for scanning have a smaller density range than one optimized for printing? In my own very limited, very amateur experience, my negatives that scan best are the ones that also print best. I'm willing to accept that this can be chalked up to my poor scanning/editing skills, but the underlying principles escape me.

Ken Lee
20-Nov-2010, 15:38
Sandy has pointed out that using Divided Pyrocat works nicely for roll film, because SBR values vary from shot to shot. For sheet film, it's better to use divided developer only when necessary. I have settled on Pyrocat HD. I used it normally for normal scenes, and divided when necessary. Why ?

In my view, the fewer the adjustments we make, the better. The earlier we make them, the better. There's a reason why the Zone System and BTZS encourage us to expose and develop a negative which prints on Number 2 paper: we're at the sweet spot of the entire process, where tones are the most... lovely.

By that reckoning, exposure and development of the negative should come as close as possible to perfect. Subsequent corrections can be applied either in the darkroom or scanner, but images look their best when further corrections aren't needed.

With digital workflow, further adjustments can be made in the image editing software. I prefer to keep these to a bare minimum, because aesthetically, upstream corrections are best. Images made this way, have a natural quality to them, a sense of presence ad luminosity.

rdenney
20-Nov-2010, 16:24
Typically film is scanned to capture all that is there. This results in a "flat" capture.

Yes, of course. I've been scanning film for a very long time and that part of the process I'm familiar with. But I practiced the Zone System long before that, though not necessarily with the density measurements that many attach to that system (I could never afford a densitometer in those days), instead thinking of it as a tool for mapping subject brightness to previsualized tones in the print.

I don't really see much difference between conventional methods and computer methods in terms of implementing the Zone System. Let me lay out my thinking and see where it leads.

Let's say we were going to print on Grade 2 paper. If we visualized EV 5 subject brightness as Zone II, let's say, then we would expect EV 10 subject brightness to fall on Zone VII, with a few assumptions. These assumptions are: 1.) Each zone is one stop of exposure different from the adjacent zones, 2.) we develop the film and calibrate our technique so that those one-stop differences yield densities that when printed on Grade 2 paper result in tones that look like Zone II and Zone VII, and 3.) we don't do anything to change the brightness relationship between those two parts of the subject.

This also assumes, of course, that the film provides usable densities at ten stops of subject brightness. That was pretty close to my experience with FP4 and HC110B developed in deep tanks, as I used to do years ago. "Usable densities" means that I can print on normal photographic paper without the highlights blocking up (a term I used decades before digital methods) and without losing shadow detail.

"Usable densities" are different for scanning, of course, and nothing I said suggested otherwise. But the concept is the same. Generally, negatives for scanning should be thinner, because if they are too thick the sensor in the scanner loses the ability to record a high enough signal/noise ratio to separate the tones. This is the same as a negative being so dense that when we try to print through it the grain overwhelms tonal gradation. So, "usable densities" for scanning means that the scanner is able to distinguish the tones represented on the film.

I get all that.

But I'm reading where Sandy and others are getting usable densities over a range of more like 18 or 20 stops of subject brightness range. Again, "usable densities" means that the scanner is capable of distinguishing the tones represented on the film. If that's the case, then I still have to visualize 10 zones in the final print. I will have to figure out how to map those 20 stops of subject brightness onto those 10 tonal zones from maximum black to paper white.

Conventionally, we map subject brightnesses to print tones by using a range of techniques. We might process the film to capture 12 steps instead of 10. We might move a Zone VII blue sky to Zone III by using a red filter. Green foliage that falls on Zone III might be coaxed up to Zone V by using a green filter and placing all the other subject brightnesses on a lower zone. All of us who have explored the Zone System using conventional wet processes have learned those techniques to one degree or another.

Now, to the assumptions I stated at the top, which are perhaps wrong. I assumed that when using a compensating developer like Pyrocat the densities in the middle values would vary about like they used to, and the densities in the highlights (particularly), instead of becoming unusably dense, would now remain within the range of "usable densities" for scanning (or for conventional printing, for that matter). So, if I place EV 5 on Zone II, EV 10 might still fall on Zone VII, but EV 14 might fall on Zone VIII, and EV 16 might fall on Zone IX, if I don't do anything to adjust them (the equivalent statement to "printing on Grade 2"). Those numbers imply a broad shoulder on the characteristic curve.

The alternative is that if I place EV5 on Zone II, EV 10 will fall on Zone V instead of Zone VII, because the 20 stops of subject brightness are more linearly distributed across the range of "usable densities".

I think the reason my question isn't making much sense to you (or anyone else) is that we have so much control over input and output tones after scanning that once we develop such that the densities are 1.) within the range of usable densities for scanning and 2.) different enough so that the scanner can distinguish them, we've done all we need to do to give ourselves the control we want in Photoshop. So, in the end, it doesn't really matter if the response is linear or not--a push in the Curves command makes it whatever we want.

My concern was that the densities in the middle of the range, where I would want good separation for flat subjects, would be so close that I would not be able to spread them out. That would make this process not so good for flat subjects.

Rick "thinking out loud, a dangerous practice" Denney

Henry Ambrose
20-Nov-2010, 16:34
snipped a bunch.....

In darkroom printing, the negative is an intermediary. Its function, among other things, is to translate the subject brightness range (SBR) into a density range that closely matches the capabilities of the photo paper. Accomplishing this, accurately and precisely, is why Archer and Adams invented the Zone System. The point is to make it relatively easy to make a print from a given negative that meets the vision of the photographer.

In digital, this paradigm is a moot point. The negative doesn't have that duty -- there's nothing to match to. In digital, all we want is a negative that's relatively easy to scan. That typically means that a negative optimized for scanning has a smaller density range than a negative optimized for the wet darkroom.

But the important point here is that the negative has no duty to match its density range to the print paper. That duty falls to the scanner, not the negative. And the scanner can typically read through whatever density range you can through at it. This is because scanners are almost always optimized for color transparencies. And trannies have a density range that is wall beyond the range for B&W negatives.



I like to think of the negative as the translator to the paper -and- as the translator to the scanner. For scanning the negative must fit its captured scene information into the range of the scanner. Once the scan is done you're gonna shoehorn the scan's range onto the paper using PS. Printing is the big flattener of range.

So in my mind the negative has the same duty to the scanner as it does to the darkroom paper.

You've got to get the scene range to the scanner. The better the density ranges fit the better and easier your work will be. You can make a dead flat negative and pull it apart to fit the larger range of the scanner or you can make one that fits the available range of the scanner and uses the full range. The second scenario is preferable.

Just because you can fix it in PS doesn't mean you should. Make negatives that fit the scanner as if you were making negatives to fit paper. Life will be good.

You do this by a little experimenting to see how your equipment works together. Its not really any different from darkroom work. I don't think you need to go to extremes in developers and techniques to get good pictures. There may be times when you want to do something special but mostly spend your energy on making a good picture that is contained in a good negative that your scanner can read.

rdenney
20-Nov-2010, 16:55
Sandy has pointed out that using Divided Pyrocat works nicely for roll film, because SBR values vary from shot to shot. For sheet film, it's better to use divided developer only when necessary. I have settled on Pyrocat HD. I used it normally for normal scenes, and divided when necessary. Why ?

In my view, the fewer the adjustments we make, the better. The earlier we make them, the better.

Ken, thanks for responding. You can see from my lengthy response to Bruce (which was typing and correcting while you typed this) that you have hit the exact point I was asking about. If I use the divided development for flat scenes, I may have to really spread them out in Photoshop, and that opens the door to posterization, but even without that, to uneven tone as normally invisible variations become visible.

So, single-bath for normal-flat scenes, and divided bath for normal-contrasty scenes.

Rick "appreciative" Denney

Bruce Watson
20-Nov-2010, 18:31
If scanners are optimized for density ranges beyond those typical for B&W negatives, why would a negative optimized for scanning have a smaller density range than one optimized for printing?

It's not intuitive. The thing is, scanners are made to handle the worst you can throw at them. In this case, it's color transparencies. They have a density range over 3.6. But their image is formed from transparent dyes.

B&W film is different in a key way -- it's image is formed by metallic silver (don't go the staining developer path right now -- I've already got a headache ;-). And scanning B&W has the same problem that optical enlarging B&W has -- Collier Effect. Light scatter from the metallic silver.

Since density is the build up of metallic silver, more density means more Callier Effect. This in turn leads to a non-linear loss of micro contrast in the highlights. IOW, they can look flat and compressed.

So, while you *can* make a B&W negative have a density range out to 3.0, if you do it will scan badly because of all the Callier Effect. Not to mention the other artifacts you get when you abuse a negative like that. It's not pretty -- looks "cooked". Try it and see.

For the record, I've been down this road before. I was convinced that if I spread the tones out over a bigger density range that I'd get more tonality in my prints. This is how I learned about what happens to film if you abuse it too much. I've got a fair number of Tri-X 5x4 negatives that are truly cooked with Dmax in the range of 3.0. Highlights are a real PITA to get any separation out of. Midtones take a lot of work too. And it's grainy as all get out. Looks more like bad 35mm than 5x4.

What I found is that the sweet spot is in the opposite direction. A little less density than what you'd want for the darkroom. The reason for this is the nature of the process. The scanner can pull a little more range out of the film while reaping the benefits of lower Callier Effect in the highlights.

But... you can go too low. If you compress your tones into too small a density range, it becomes increasingly difficult to pull the tones back out for the print.

You'll have to experiment some to find the sweet spot for your equipment.

Jay DeFehr
20-Nov-2010, 20:13
Thanks for the breakdown, Bruce. Your explanation squares with my limited experience; negs that print easy, scan easy. I like my negs on the thin side in the darkroom, too. If I need to bump the contrast, I prefer to do it with the printing paper, but I don't have a lot of patience for difficult negatives. Any negative of mine that requires a lot of adjusting probably won't get printed. I suppose my approach to printing is similar to Ken's approach to scanning- the less I have to fuss with it, the better the print.

Lenny Eiger
20-Nov-2010, 20:31
Thanks for the breakdown, Bruce. Your explanation squares with my limited experience; negs that print easy, scan easy. I like my negs on the thin side in the darkroom, too. If I need to bump the contrast, I prefer to do it with the printing paper, but I don't have a lot of patience for difficult negatives. Any negative of mine that requires a lot of adjusting probably won't get printed. I suppose my approach to printing is similar to Ken's approach to scanning- the less I have to fuss with it, the better the print.

Well, I have to give Sandy his day and Bruce his... however, there is a middle ground that works for me. I am currently using Xtol 1:1 in a Jobo with 8x10, mostly Delta, some TMY2.

A long time ago, I migrated to printing in platinum. I found that it responded well to a longer tonal range. Specifically, at the time, that was a density of 1.8 or 1.9. I have noticed that these negs work extremely well for scanning. The work better, and have more tonal spread (and much richer print) than negs developed to 1.0 or so. I do not know why I do not experience Bruce's suggestion of the Callier effect at this density. Grains are very well articulated by the scanner from what I can see.

It also does not work (for me) to develop a neg out to a higher density than 2.0 or 2.2.

It depends a great deal on the contrast range that you want to print with. Higher contrast can work well with a less dense negative. However, a full spread, as subjectively defined by myself, works best in the 2.0 range.

I haven't had a chance to try Sandy's method, and one of these days I will. Barring that, things are doing great. I have prints from recent work where there is enough inherent texture to give people the feeling that they are "there". This is pretty much what I have been after and I'm happy with the current results. Others have other aesthetic concerns... where this type of texture is not necessary to their images.


Lenny
EigerSudios

Jay DeFehr
20-Nov-2010, 21:02
Lenny,

Thanks for sharing your experience. I think Bruce's description of the Callier Effect, and its causes might explain some of my own experiences. Last time home, Julia scanned some 35mm Tmax 400 (original) developed in Halcyon, my superfine grain developer. I didn't have much hope for the negs because the highlights looked very dense to my eye. I was very surprised to see they scanned beautifully. I think the fine grain must have been a contributing factor to the success of the scans. Likewise, I think stained negs have an advantage in that the stain does not contribute to the CE the way grain does. These are all just hunches and suspicions on my part, but the experts here seem to support or explain some of them, and that's encouraging.

Ken Lee
20-Nov-2010, 21:15
So, single-bath for normal-flat scenes, and divided bath for normal-contrasty scenes.

I use single-bath for all scenes except those which are very contrasty. Single-bath can work fine for N-2, but after that, there's no substitute for divided developer.

Another other advantage of divided developer, is that you process all films at the same temperature and for the same time.

I still need to experiment further with divided developer in outdoor scenes which contain clouds: in particular, what happens when you use a yellow or orange filter to darken the sky. Divided Pyrocat keeps the clouds from becoming blocked, in a big way.

sanking
21-Nov-2010, 06:05
When we talk about compensating development one generally assumes that it is accompanied by compression in the shoulder of the film curve. This is true with most films and single bath developers. However, it is my experience that it is not true with most films when developing in true two bath developers, i.e. those where the film absorbs the developer in Sol A but no development takes places. With these developers you usually see a very straight line curve with a short toe and very little shouldering. I can not speak to every film out there but this has been true of some of the common ones I have tested, including Acros, Tmax100, TMY, FP4, etc. Every film is slightly different but in general a fairly straight line is typical with development in true two bath developers.

As a general rule I believe there is no reason to develop negatives to a CI of more than about .50 if the negative is to be scanned. A negative that is exposed correctly and developed to a low CI will have better sharpness and finer grain than one developed to a high CI. On the other hand I have been able to scan and print some of my older negatives that were developed to a very high CI for printing with carbon transfer or pt/pd. However, if you have a negative with a very CI you probably will not be able to make a good scan of it with a cheap consumer scanner because the dynamic range of cheap scanners is quite limited.

Sandy

Bruce Watson
21-Nov-2010, 09:04
OK, here's an alternate way of looking at it, using darkroom analogies.

The Zone System was designed to get a negative that was easy to print on #2 paper. One did this by understanding exposure and development controls. As technology progressed, we learned that different enlarger types needed differently processed negatives to get that goal of easy to print on #2 paper. That is, condenser enlargers want a Zone VIII of around 1.2, while diffusion enlargers want a Zone VIII of around 1.3, both for the easy printing on a #2 paper. [I think I got that right, but it's been a lot of years since I did any darkroom printing, so please correct me if I'm wrong on the numbers]

Think of a scanner as a different technology enlarger. What I've found is that my scanner (and they'll all be somewhat different no doubt) wants a Zone VIII density of around 1.0. Different technology, different needs.
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Now to papers. In a scanning workflow there is no equivalent of a graded darkroom paper. All papers print the same; there is no #2 paper. Zero is black, 255 is white (let's keep it at 8 bits for this discussion, and assume a well linearized/ICC profiled printer).

What's this mean to us? It means that we don't have to control our negatives as accurately or precisely as we do for the darkroom. Think about it. No paper grades means it's not possible to translate the density range of the negative to the tonal range of the print. It's undefined.

In practice, this means that if you expose two negatives identically, and develop one to a Zone VIII of 1.0, and the other to a Zone VIII of 1.2, scan them both and print them both, you won't be able to tell the difference in the prints. At least, you wont be able to tell the difference like you could with a darkroom print -- the tell tale contrast difference won't be there. In the darkroom you could have printed one on a #3 (or 3.5) and the other on a #2 and achieved a similar range of tones. But not quite. There's a difference between a #2 paper and a #3, which is why so many prefer to print on #2.
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What it all comes down to is pretty simple. If you are ever going to print in the darkroom, you should optimize for the darkroom. It will scan just fine. If OTOH, you are *never* going to print in the darkroom, you might as well optimize for scanning. This will get you another, say, 5%. It'll be a touch sharper, a touch finer grained, show a touch better highlight micro-contrast, will take a touch less work in photoshop, etc.

We aren't talking a huge difference here. It's about like optimizing for a condenser enlarger vs. a diffusion enlarger. Which shouldn't be surprising to anyone here.
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Scanning likes some things disproportionately to the darkroom world. Scanning responds well to finer grain. It responds well to minimal density. It likes sharpness and micro contrast.

Basically, scanning likes modern films. TMX is perhaps the easiest film I've ever scanned. TMY-2 is a close second.

I speculate that this is because of the thinner emulsion and flatter grain structure. Less light scatter, and perhaps more controlled light scatter. IDK.
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Finally, there is absolutely no reason in the world for anyone to take me at my word. It's easy, very easy, to verify this for yourself. All it takes is a little experimentation, a little work, scanning the same images developed to different Zone VIII densities (or different contrast indices if you think that way). Basically, all you are doing to changing the slope of the response curve a bit by developing at different times.

What have you got to lose? A few sheets of film and a few hours of your time. What you can gain, is knowledge of your system. Just sayin'.

Jay DeFehr
21-Nov-2010, 09:08
Sandy,

If 2-bath developers produce straight film curves, in what way can they be considered "compensating" developers?

I know there is a difference in 2-bath development compared to single bath development. 2-bath development is limited in a different way than single bath development is. A typical, general purpose, single bath developer is capable of developing a film to gamma infinity, given enough time. This is not necessarily true of a 2-bath developer, in which the potential contrast is limited by the composition of the developer, and not by the other development parameters.

My question is; can we truly call this type of development "compensating"? If 2-bath development doesn't change the shape of a film's curve, but limits its slope, wouldn't a term like, "contrast limiting" be more accurate? I think there is an argument to be made that a contrast limiting developer is more desirable under most circumstances, than a compensating developer would be, and I think the more accurate terminology would simplify discussions about this type of developer, and help to dispel some of the misconceptions about them.

What I'd like to know about developing film for scanning is the following; at what point is a negative too flat (too low CI), and what are the consequences for the digital output (print or negative)?

Bruce Watson
21-Nov-2010, 09:10
In my view, the fewer the adjustments we make, the better. The earlier we make them, the better. There's a reason why the Zone System and BTZS encourage us to expose and develop a negative which prints on Number 2 paper: we're at the sweet spot of the entire process, where tones are the most... lovely.

No argument there.

But... there is no #2 paper if you are printing digitally.

Bruce Watson
21-Nov-2010, 09:26
If I use the divided development for flat scenes, I may have to really spread them out in Photoshop, and that opens the door to posterization,...

Well, it depends how you scan. If you set your white and black points to match the top and bottom of the image's density range, the scanner will capture the full range of tones in your specified range and spread them out of the digital range of 0-255 (8 bit). You don't have to do this in photoshop.

If you scan in 16 bit mode, your chances of posterization are very small. You have to do some serious manipulation to posterize an image with a 16 bit capture.

I've got a couple of prints around here somewhere that I made years ago. The capture was in fog, my spotmeter told me the SBR was a whopping single stop. I put said SBR at Zone V. When I scanned it the first time I scanned just that 1 stop range. This resulted in a lovely full range print -- lovely tones in the shadows, midtones, and highlights. Nice contrast. But... no hint of the fog.

So I scanned it again and included a much wider range. The resulting histogram in photoshop was scary looking -- all the image information right in the middle with lots of empty space on either side. That print, with most of the image centered around Zone VI-Zone VII was ethereal. And that's the print that was much closer to my vision when I made the photograph.

I was a good experiment. What's interesting about this to me is that both prints are really good technically. The expanded tonality of the first print is, well, excellent. Nice and smooth from black to white. The tonality of the second print is just as nice, but the range on the print is much more limited.

I'm just sayin' that the flexibility is there. With scanning, it's certainly possible to "Expose for the shadows and let the highlights fall where they may." IOW, it's certainly possible to eliminate all N+ and N- developing. This would be madness in the darkroom, but it works just fine when scanning.

Bruce Watson
21-Nov-2010, 09:29
Well, I have to give Sandy his day and Bruce his... however, there is a middle ground that works for me. I am currently using Xtol 1:1 in a Jobo with 8x10, mostly Delta, some TMY2.

A long time ago, I migrated to printing in platinum. I found that it responded well to a longer tonal range. Specifically, at the time, that was a density of 1.8 or 1.9. I have noticed that these negs work extremely well for scanning.

I don't doubt you. I found that Tri-X would do fine for me up to a Dmax of around 1.5. I suspect that T-grain films perform better at higher densities. I've just never tried it.

Kirk Gittings
21-Nov-2010, 13:11
Bruce,

I think what you say is very true when working with a drum scanner, but I have found consumer level scanners like the Epson 750 have trouble with dense highlights or thin shadows compared to a good drum scan. NO?

Bruce Watson
21-Nov-2010, 15:01
I think what you say is very true when working with a drum scanner, but I have found consumer level scanners like the Epson 750 have trouble with dense highlights or thin shadows compared to a good drum scan. NO?

Most of what I know from consumer flatbeds comes from an old Epson 2450. It didn't have much trouble scanning shadow areas. In fact, it could pick up detail I had trouble seeing on the light table. What looked like lightly fogged film would often result in some level of image detail from the 2450. It did have more trouble with the highlights, but only when they got to be pretty dense. It's been a while, but what I remember was it began to strain in the sub 2.0 range.

I would expect more modern consumer flat beds would be better performers. Are they? IDK.

But it's true that an Epson flatbed can't play in the same league as a drum scanner. I'm always amazed in particular at what the drum scanner does with the shadow areas of a B&W negative. That scanner can pull image information seemingly out of thin air. Density doesn't faze it at all; it feels like it could read through a black hole. And image detail that's so small I can barely see it on the light table with a 10x loupe, that the old 2450 would render as a smear at best, the drum scanner renders sharp, crisp and clear.

But that shouldn't surprise anyone. When it was new it was a $100K machine. Not state-of-the-art, but it could see it from where it was. So comparing a drum scanner to an Epson flat bed just ain't fair.

That said, I found that both scanners responded better to thinner negatives. To a point. You can certainly go too thin. It's been so long I can't reliably remember (I'm not big on keeping a journal for my personal experiments), but I seem to recall that the Epson wanted somewhat more density than the drum, but both wanted somewhat less density than a standard darkroom negative. Thus the admonishion that individual testing is the only way to find out what's optimum for anyone's personal equipment and workflow.

sanking
21-Nov-2010, 15:17
Sandy,

If 2-bath developers produce straight film curves, in what way can they be considered "compensating" developers?



Jay,

An interesting question and one that deserves more input and study.

I have not studied the literature to determine exactly what is meant by a compensating developer. My own understanding of the term is that it means a developer that compensates for a very high subject brightness range. I have thought that there could be various mechanisms that could deliver the compensation, including highlight compression as well as the two-bath method of limiting contrast. But I don't know for a fact that my understanding of the term is consistent with the historical use of the term compensating.

Sandy

Jay DeFehr
21-Nov-2010, 16:55
Sandy,

I've always thought the term referred to preferential development of low values by the exhaustion of the developer in the highlights, but I think that's only one usage of the term. I think your broad definition better accounts for all the ways the term is used, and includes the contrast limiting mechanism of 2-bath developers. Thanks for your insight.