Proof to Print: the contrast difference

[Ulophot]

As I was checking my film development time with a new thermometer over the weekend, it occurred to me that, although the phenomenon is widely recognized by experienced B&W darkroom workers, the loss of contrast from contact print (proof) to enlargement is rarely mentioned in books and tutorials discussing the process, including the Zone System. I don't recall offhand whether Adams mentions it, though he speaks of camera and lens flare/internal reflection diminishing contrast. I don't remember hearing it from Picker's printing video. Many photographers prefer to make a distinctly softer contact, to reveal full detail, and then tend to increase contrast in the enlargement. I find now that the difference tends to be a 1/2 grade, so that a 1 1/2 proof is close to 2 in enlargement.

The issue presented itself to me a few years ago as I was returning to the darkroom after many years' absence, testing for a different developer, a new meter -- in short, plenty of variables. I was at first shocked that, after carefully controlling for a "perfect" Zone I - VIII in the 4x5 contact (for the densitometrists reading this, I don't densitometrize), my initial enlargements were showing I - VI 1/2 or VII. A year of studious weekend work later, matters were much more under control, and the contrast difference no longer appeared so extreme. It may largely have been due to my previous concentration in photojournalistic photography, mostly 35mm, in which I learned to coax a print from just about any negative and, although I certainly tested quite a bit, after such a long hiatus and shifting formats, I was both more aware of the difference and surprised at how much relearning I had to do! I don't think I used to proof at 1 1/2, but I did prefer a gentler, more "supple" negative, since extra-long contrast ranges were par for the course.

Just a thought.

[Vaughn]

Depends on the light source for the enlarger, also -- differences in development are given in the film companies' instructions for use (enlarging) in condenser and diffusion enlargers.

[ic-racer]

You can projection print a step wedge and contact print the same wedge. The difference between the two will show how much flare you have in your projection printing system.

[Drew Wiley]

I never proof, but strategize full exposures with simple test strips the same day. Saves a lot of time and error. If I make contact prints instead of enlargement, it's for their own sake, and I optimize them accordingly. Other than the f/stop setting and the time, or other specific enlarger controls, I ignore all the Zone and Grade talk; it's just a distraction totally superfluous to making good prints.

[Jim Noel]

When I became concerned about the loss of sharpness and contrast between contacts and enlargements, I began going to larger cameras so I could contact all final images. My 4x5's have mostly gathered dust for about 20 years. Needless to say the enlargers are suffering the same fate.

[Pere Casals]

the loss of contrast from contact print (proof) to enlargement is rarely mentioned in books and tutorials discussing the process, including the Zone System.


It is often mentioned, a contact print has the same contrast than a condenser enlargement, if no excessive flare. A diffuser enlarger has lower contrast, and negatives for it may be developed longer for a higher C.I.

Even it is mentioned in the TMX datasheet (Page 2, Processing section): "To print negatives with a condenser enlarger, you may need to adjust the contrast by reducing your development time; see “Adjusting Film Contrast.”

https://imaging.kodakalaris.com/sites/prod/files/files/products/f4016_TMax_100.pdf

[Drew Wiley]

Not logical. Condenser enlargement still potentially has bellows flare, reflection issues off glass, lossiness due to the lens, etc. This is particularly the case since most condenser enlargers are rather old. Contact prints have none of these issues.

[Vaughn]

"Proof prints", as I consider them, are meant to be low contrast. As you mentioned, this allows the photographer to see what detail the negative has in the shadows and highlights. Proofs show what is possible with the negative, not what the final print will look like. I use to make them, but I find it easier now to read the negative directly...an advantage with large negatives!

[Drew Wiley]

I do that even with 35mm negs, Vaughn. Reading color negs is a bit of a headache, however, regardless of size, due to that orange mask. I look at them through a med blue filter, which helps distinguish certain otherwise indistinguishable hues, but these are, of course, inverted color-wise and counter-intuitive. When testing any new color neg film, I might shoot it in 120 and order up a med quality scan which allows me direct viewing; but in the darkroom one always needs to fiddle around awhile to get ideal results. I did bag a hole in one yesterday. I can usually determine in just a few minutes via test strips where to go with b&w negs, even using multiple paper choices, different paper developers, and even several different enlargers. But on any given day, it's interesting how the neg you thought would be easy turns out to be hell to print the way you want it, and the neg you almost threw out turns out magnificently right away. Hope that's not the case with the pancake mix I put in my food kit for the next backpacking trip. I just cooked up the leftover powder for breakfast here this morning, and it seems a bit heavy on the baking soda - a boxed premix, and not my fault, but in the high country you can't redo it!

[Pere Casals]

Not logical. Condenser enlargement still potentially has bellows flare, reflection issues off glass, lossiness due to the lens, etc. This is particularly the case since most condenser enlargers are rather old. Contact prints have none of these issues.

Condenser type is less prone to flare from the bellows, as condensers concentrates most of the light in the lens glass, while a good diffuser type requires a better design to have low flare from bellows. Both types may have some flare from the lens, and from the wall. Paper reflects most of the lights it receives, say 90%, if the wall is white then some light can be reflected back.

[Jerry Bodine]

After modifying my E6 5x7 Omega diffusion enlarger's light source to LEDs, I made a number of tests with Stouffer step wedge to check how it performed with Ilford under-lens filters. I was always wondering about a difference in contrast between a contact and an enlargement, that I'd read about; so while doing these tests I first projected the step wedge for a Gr2 print (masking the wedge as much as possible in the carrier to minimize flare), then made a contact print of the wedge with same Gr2 filter and unchanged enlarger height). Checking the two results with a reflection densitometer showed a definite contrast difference - results of the two prints are attached. But I suppose the inherent flare from the enlarger lens/bellows in the projection print could explain the difference - I may never know for sure. BTW, the two curves have been adjusted to intersect at a .09 density (Zone VIII) in order to show the difference in slopes more easily.
If it helps in reading the attachment, notice that it shows at RLE 1.7, for example, the difference in the blacks is substantial; density of 1.45 represents Zone III + 1/3 in the projection vs Zone II in the contact - a difference of at least one zone) - even though the highlights are unchanged. These measurements were done on DRY prints, so the effects of dry down are included.

[Drew Wiley]

There are SO many variables, and simply no way to make an accurate comparison between the degree of contrast difference between a contact print and an enlarged one unless if is user specific, with a very tightly defined use of personal equipment and methods. Not one of my enlargers would match the archaic published stereotypes about the amount of flare. I measure such things with an extremely accurate easel densitometer. Even choice of specific lens is factor, along with angle of incidence, aperture size, type of coating,etc etc, etc, ad nauseum. You really have to do your own testing and measurements, or better, ignore the whole question and just have fun.

[Pere Casals]

But I suppose the inherent flare from the enlarger lens/bellows in the projection print could explain the difference


Post Exposure book (Page 59: http://ctein.com/PostExposure2ndIllustrated.pdf) explains how to measure flare, you only need an opaque strip in the negative carrier and a way to meter.


A bit of Flare is not necessarily bad, it also works like a preflash. Anyway it modifies the paper curve, delivering a relatively shorter toe, as your curve shows:

https://www.largeformatphotography.info/forum/attachment.php?attachmentid=192845&d=1561592790



AA liked the diffuser enlargers, but IMHO it all depends on many factors. Now I play with a condenser enlarger and I find that it has a superior "punch", but this is a very personal opinion.

A good illumination perhaps is a mid point between condenser and diffuser, in a 138 this is inserting a frosted glass (more or less frosted) between the bulb and the mirror, in fact Durst has an original accessory for that, "the LAPAL ground-glass diffusing screen" that can be placed in the filter drawer.

[Drew Wiley]

My gosh, Pere, I've been in Ctein's darkroom. It's just a lot of black polyethylene hung in his garage and a modified basic Beseler enlarger which does have a bit of flare issue. AA also used relatively primitive equipment, but in a dedicated space. That's all perfectly fine once one is comfortable with their own equipment and setting. But there are in fact ways of dramatically improving equipment performance over traditional expectations found in past literature. And I, for one, certainly don't like the thought of "automatic flare", especially in color printing. Diffusion ABOVE the carrier has nothing to do with that topic. You have a fun imagination and it might serve you well over time, but really do need more time in the darkroom so you can stop wildly guessing about all of this. I have three commercial Durst enlargers, and none of them is as primitive as your stereotype. There is an old condenser head somewhere in a box on a loft; but I sold the actual condensers long ago. Some of us have better ways of cooking meat. Condenser heads themselves can be tricked out in different ways which some people find rewarding; but flare is a different issue which begins below all that. I assume you have adjustable masking blades within your 138 head, right below the carrier.

[Tin Can]

Pere, i downloaded the ctien link, hopeful copyright is now open.

Started reading at page 59 and found the topic very interesting.

I will read more later from the beginning.

Thank you


Post Exposure book (Page 59: http://ctein.com/PostExposure2ndIllustrated.pdf) explains how to measure flare, you only need an opaque strip in the negative carrier and a way to meter.


A bit of Flare is not necessarily bad, it also works like a preflash. Anyway it modifies the paper curve, delivering a relatively shorter toe, as your curve shows:





AA liked the diffuser enlargers, but IMHO it all depends on many factors. Now I play with a condenser enlarger and I find that it has a superior "punch", but this is a very personal opinion.

A good illumination perhaps is a mid point between condenser and diffuser, in a 138 this is inserting a frosted glass (more or less frosted) between the bulb and the mirror, in fact Durst has an original accessory for that, "the LAPAL ground-glass diffusing screen" that can be placed in the filter drawer.

[Jim Noel]

It is often mentioned, a contact print has the same contrast than a condenser enlargement, if no excessive flare. A diffuser enlarger has lower contrast, and negatives for it may be developed longer for a higher C.I.

Even it is mentioned in the TMX datasheet (Page 2, Processing section): "To print negatives with a condenser enlarger, you may need to adjust the contrast by reducing your development time; see “Adjusting Film Contrast.”

https://imaging.kodakalaris.com/sites/prod/files/files/products/f4016_TMax_100.pdf

The passage of light is altered and even restricted to a degree regardless of light source. Try comparing a condenser enlargement with the same portion of a contact print. You shouldn't need a magnifying glass.

[Pere Casals]

I assume you have adjustable masking blades within your 138 head, right below the carrier.

The Nega 138 ANR+glass carrier, with masking blades, of course. But the big source of flare I found was the white wall behind the enlarger, the paper reflects most of light and this illuminated the white wall.





Diffusion ABOVE the carrier has nothing to do with that topic.

IMHO it has.

It allows to get a good balance between diffusion and condenser. Condenser prints have a lower "Proof to Print contrast difference" compared to diffusion prints, but also we have a mid point, say semi-diffusion or semi-condenser illumination, we may adjust the degree of collimation to suit our taste.




The passage of light is altered and even restricted to a degree regardless of light source. Try comparing a condenser enlargement with the same portion of a contact print. You shouldn't need a magnifying glass.

Jim, I agree but regarding contrast a condenser print should be closer to a contact print than a diffusion print, in special if the illumination for the contact print is a point source.

Yes... a contact print... nothing matches that...

[Drew Wiley]

White wall? Ever hear of black paint, or even a big sheet of black matboard? But you're confusing terminology. Your wall is not a flare, but a reflectance issue. Flare should be considered as an internal problem, in the enlarger system itself, including the lens and bellows. Diffusion above the carrier is not a flare issue either. It does affect the angle of incidence of light hitting the carrier, and related consequences, but need not be a flare problem, since your intended negative areas should be suitably masked off. Flare is wasted light afterwards, that gets bounced around where it does not belong, although that could potentially include internal reflections not only in the lens, but within the carrier glass itself. There are some valid arguments about the manner light is collimated in relation to grain reproduction in condenser versus diffusion systems, or hybrids of these. But the old adage that diffusion systems are lossy in contrast can be drastically mitigated if one goes to a bit of extra effort to control wasted light. I find it an archaic argument, but nonetheless relevant to those who use conventional enlarging equipment. Ctein's situation was a little different. He experimented mainly with various color media to the extent necessary to give an informed opinion. More recently, he's gone over to inkjet printing via personalized profiles, and nowadays is writing SciFi novels. But in the past he primarily worked with a version of the dye transfer process which goes straight from an original color neg to three separations directly onto Pan Matrix film, without the intervening b&w separation negs and multiple masks necessary when working with chrome originals. But the contrast and saturation of the respective dyes, either method, is easily lowered or boosted via a pH change. That's quite different form most forms of color printing where contrast needs to controlled in other ways, and where, in my opinion, it's wisest to control flare as much as possible. Older workers who used chromogenic prints largely for soft portraiture and so forth never realized the remarkable potential of it today for truly crisp brilliant prints, like the one I'm working on this afternoon. But even in black and white printing, I prefer less flare for sake of excellent microtonality with very high quality enlarging lenses, rather than simply boosting the paper contrast grade, which is easy to do using today's excellent VC papers, but not quite the same thing. A clean-light print has something special to it, more analogous to what you get doing a contact print - no, not to the same degree, but with the advantage of bringing out more perceptible detail view enlargement.

[neil poulsen]

An interesting point. This may help address a question I've been wondering about lately.

To some degree, I directly take this into account. As part of working with a paper, once I find the minimum exposure that gives maximum black (at a given enlarger height), I determine the film density that gives me a Zone 8 tone that I like. I use Ilford Warmtone Glossy paper, and my desired Zone 8 density for this paper with no enlarger filtration is 1.35 density units. The development time that gives me that density becomes my normal development.

But then during printing, I end up adding higher contrast yellow filtration to get the best print. It's usually between 20 and 30 units. I've been wondering lately, since I test without filtration, why do I feel the need to increase contrast when I print? I can think of other reasons, but maybe what you suggest is one of them.

So, perhaps AA addresses this in his books indirectly, in that part of his approach advocates using the best paper contrast for the print.

[Drew Wiley]

I don't think AA's books would be of much help in that respect. Modern VC papers are complex and not all current products are the same with respect to exposure variables. I also believe than by artificially limiting these to some sort of eight zone model deprives you of much of their real versatility. Yes, you need all your information there in the negative to being with, and within a reproducible reproduction range; and the Zone System might help you do that. But trying how to "previsualize" and mechanically determine all that in advance is a bit unrealistic. I very much doubt that was the case even with AA, given the fact it could take him an entire day to pin down the printing strategy for a select (versus commercial use) negative. In the case of MGWT you might have discovered that using pure blue, or alternately, maximum magenta, light does not guarantee you the highest DMax, but that you need a bit of yellowish white light too, or yellow per se. These are among the issues for which hands-on experience with a specific papers is way more important than generic theory, especially when such theory is based on films and papers long gone. Graded talk is largely meaningless nowadays, unless you're working with one of the few remaining graded papers. Since VC papers can be very easily fine-tuned, issues like internal flare in an enlarger can be almost instantly neutralized, unless it's a gross problem. Wall reflection is a no-brainer to control. I am perhaps fussier because all but one of my enlargers has to do dual duty for very precise color work as well. Plus I do very nitpicky things with enlargers and film, like generating very predictable precise masks and internegatives. But I suspect most people here don't have such tight parameters.

[Vaughn]

Proofing, for me, was just to see what was on the negative -- it had very little to do with final image.

[Pere Casals]

But trying how to "previsualize" and mechanically determine all that in advance is a bit unrealistic.

It depends on the scene... but IMHO previsualization can be very useful to take decisions in the taking and in the processing.

[Drew Wiley]

I suspect we all somehow previsualize how we think a resultant print should come out in the darkroom, at least subconsciously. But the notion you're going to peg it all in advance with some rote formula is very unrealistic. There a too many variables, light changes, etc. In a production studio or lab where everything is artificially controlled is a different situation. The point is to get a versatile enough negative to be reasonably malleable in the darkroom, not futz around forever with a calculator in the field.

[Pere Casals]

The point is to get a versatile enough negative to be reasonably malleable in the darkroom, not futz around forever with a calculator in the field.

Well... this is a YMMV.

I think that we can agree that usually a print has a priority: mids need a range and a gradient, this is the easy chapter.

Then we have to compress (more or less) deep shadows in a range left by the mids, and we also need to compress (more or less) the highlights in the other range left by the mids. This is the difficult thing, how we compress like we want the deep shadows and highlights in the narrow ranges the mids don't use. For both shadows and highlights we may want an extension and a local "gamma", so we have 4 additional factors to adjust after we have the mids in place, a lot of factors!


1st> A way is capturing all the scene range linearly with a linear film, say TMX. Then we have a flexible negative, but then we have to work the shadows and highlights compressions in the printing (the 4 factors), and this may not be easy, or it can be difficult we obtain what we want.


2nd> Another way is using a film/processing delivering more an S curve, so we compress shadows in the toe and/or highlights in the shoulder, this is the classical ZS approach, I guess, we place in Z-II those shadows of the scene we want compressed, with that job done we have more freedom to work mids/highlights in the printing. Karsh, to mention an artist using the toe to compress shadows.


Using the second approach requires a pre-visualization of the final print.


IMHO, with the popularization of VC papers the 1st approach became more feasible, simply because VC allows to burn shadows with 5 contast grade and highlights with 00 grade, this is (IMHO) the Sexton's approach, a linear taking, a flexible negative, and a very well controlled printing.


...but the Karsh's approach (to say a name) is not bad at all. IMHO high end portraiture requires a higher degree of control in the shadings (face volumes) and in the highlights (textures in the glares), so having the shadows solved in the taking is what allows an easier job and a better result in the printing.


hmmm, making a really sound darkroom print is not that easy, and there is a lot of YMMV in the path. This is IMHO, and I'm only a rookie in the darkroom.

[Drew Wiley]

Well, yes, compressing is one way of doing things. It is the correct term for what you're describing. Its synonyms are squashing, squishing, stomping, flattening, making lifeless, devoid of discrete tonal differentiation. That's why I advocate alternate methods that do not involve compression.

[Bernice Loui]

Which more often than not produces a flat-dead lifeless print.

All that theory and etc does much of nothing once the viewer demands a worthy image with life and expression of the artist's emotions to stir the viewers emotions.



Bernice


Well, yes, compressing is one way of doing things. It is the correct term for what you're describing. Its synonyms are squashing, squishing, stomping, flattening, making lifeless, devoid of discrete tonal differentiation. That's why I advocate alternate methods that do not involve compression.

[Keith Fleming]

Somewhere in the back of my mind is a memory of reading a piece by a well-known photographer (I cannot recall who it was) who wrote that once you achieve a satisfactory print, moving up to the next larger paper size called for a full grade of contrast increase. The article said this held true with either graded paper or contrast filters on multi-contrast paper.
Keith

[Vaughn]

I do believe that each print size has its own requirements to be successful. And 8x10 and a 16x20 print of the same image might easily require a different 'look' to be successful. They work differently -- viewing distance, attention to print detail, etc. The 8x10 might have areas of pure black shadows that work wonderfully when those areas are small, all of a sudden become objectionable when enlarged 4 times in area in the 16x20.

Or it just might be that when making bigger enlargements, the enlarger is higher, larger aperatures are required (and/or longer exposure times), and there is more unsafe light bouncing around to increase flare.

[Pere Casals]

Somewhere in the back of my mind is a memory of reading a piece by a well-known photographer (I cannot recall who it was) who wrote that once you achieve a satisfactory print, moving up to the next larger paper size called for a full grade of contrast increase. The article said this held true with either graded paper or contrast filters on multi-contrast paper.
Keith

IMHO this is a YMMV, as Vaughn points in a larger print we have two factors, one (possible LIRF) increases contrast (if a longer exposure) and the other one adds flare, and flare tends to deliver a less contrasty result.



I do believe that each print size has its own requirements to be successful. And 8x10 and a 16x20 print of the same image might easily require a different 'look' to be successful. They work differently -- viewing distance, attention to print detail, etc. The 8x10 might have areas of pure black shadows that work wonderfully when those areas are small, all of a sudden become objectionable when enlarged 4 times in area in the 16x20.


This is a interesting point I was not much aware.



Or it just might be that when making bigger enlargements, the enlarger is higher, larger aperatures are required (and/or longer exposure times), and there is more unsafe light bouncing around to increase flare.

A long exposure would increase contrast because lights (dense negative areas) would have more LIRF, while a larger print would catch more flare from the walls, IMHO the area behind the enlarger has to be black, for BW it can also be red.





That's why I advocate alternate methods that do not involve compression.

Drew, obviusly an scene may contain way more dynamic range than a print may support, in that case you have to compress more or less in certain or all tonal ranges, if not you would only be able to print scenes having a range equal or lower than the one a print may sport, this is your subject is in the shadow.

A master printer is able to compress the different tonal ranges in the scene (and/or adjust local exposure) to deliver a sound depiction of a higher DR scene in a medium than has a reduced DR. Me, I also love BW slides because I can display 20X or (even) 40X more dynamic range than with paper, this is 5 additional stops, if you try to place that DR on a paper you'll have to compress something, wanting it or not.

[Drew Wiley]

What you need to differentiate in this discussion, Pere, is the difference between a suitable NEGATIVE with a full scale of well-differentiated values can potentially use, which well might suffer from compression, versus how to selectively interpret all that information on the negative when you get to printing it. Don't tell me what a "master printer" can or cannot do until you start speaking from experience instead of hypothesis. And yes, slides have a special beauty illuminated from behind. Now, if you really know what you're talking about, go try to put that same impact in a print. Then we can decide who is a "master printer" or not.

[Drew Wiley]

Keith, maybe somebody taught that rote grade shift size, but it's largely nonsense. Even before VC papers were improved, I did just about everything, every size, on Gr 3 papers. Any paper of real quality allowed a degree of contrast control simply through shorter and longer development. But I'm speaking in principle; going into detail would have to be product-specific. Going from a tiny print to mural size would obviously involve a modification of strategy. But otherwise, I consider it an old wives tale.

[Bernice Loui]

Most GOOD silver gelatin black & white papers are grade 3 or grade 2. Once past these paper grades, good print making difficulties will occur.

There is some ability to do contrast control during paper development, but most of contrast control comes from making a GOOD negative. IMO, the best way to achieve fine contrast control is contrast masking. Decades ago friend owned one of the BIG photo print labs in San Francisco. He got a contract to do poster size reproductions of Ansel Adams exhibit PR prints using AA original prints. His solution to achieving a reasonable large prints for publicity display was to use contrast masking to control print contrast. Worked out good. There was a time when SF bus stop shelters had ad prints in them, this is one of the labs that did a lot of those ad prints decades ago.

And no, these prints would have never been as good if they were contrast flattened.

Bernice

[Vaughn]

Vaughn: I do believe that each print size has its own requirements to be successful. And 8x10 and a 16x20 print of the same image might easily require a different 'look' to be successful. They work differently -- viewing distance, attention to print detail, etc. The 8x10 might have areas of pure black shadows that work wonderfully when those areas are small, all of a sudden become objectionable when enlarged 4 times in area in the 16x20.

Pere: This is a interesting point I was not much aware.

Thank you for putting up with my typos! I've been having fun making platinum prints directly from negatives on 120 film (various formats, but usually 2 1/4 sq). Those images work very differently than larger images and I must compose the small images very differently than my LF images. Due to the small size, I found that form becomes far more important than detail. There is little room for the eye to travel around inside the little square -- to bring the viewer into the image. So other means must be used to keep the viewer's attention (subject, form, emotion, etc). It has been quite educational and has strengthen my larger work.

[Drew Wiley]

I have one of those little 2-1/4 carbon contact print Vaughn made, and its small size does not at all detract from its intricate beauty. In fact, it kinda draws you in, in a way a bigger print wouldn't.

[Vaughn]

Thanks, Drew.

[Drew Wiley]

Bernice, Ansel never seemed to get a handle on masking, so it's interesting that the SF lab which printed some of his negatives used it. It was already routine in color printing, and it's for sake of color work that I got proficient at it, then merely transposed those skills to part of my black and white tool kit. It's those very contracted-out images, the most complete collection of AA's murals ever assembled up to that point at least, that I shared a public exhibition with right after his death, so got to examine them quite well. It is my understanding that he was on hand to at least supervise the printing, even though technicians handled the rest. The feel of those images in big size is quite different from say, 8x10 neg up to 20X24 print. They're a lot softer and more poetic, and just wouldn't hold up well at higher contrast and his usual colder tones because the original negs are pretty grainy and not all that sharp by modern standards at least. But I was strictly color printing at that point in time, highly detailed Ciba prints, and it made an interesting complement.

[Pere Casals]

original negs are pretty grainy and not all that sharp by modern standards at least.

Drew, that SF lab could do something wrong... Probably 8x102 AA negatives can be insanely enlarged with perfect quality. How big were those prints in meters?

[interneg]

Drew, that SF lab could do something wrong... Probably 8x102 AA negatives can be insanely enlarged with perfect quality. How big were those prints in meters?

No, it sounds pretty much correct for negatives of that period. Before the advent of significantly more advanced controlled crystal growth techniques in the 1950's (graded iodide with high monodispersity) & commensurate sensitising methods & use of acutance dyes, together with the advent of thinner multilayer constructions, most films of reasonable speed were nowhere near as crisp & sharp as we might assume today. Polydispersity gave reasonable latitude at the cost of various other problems & the move to monodispersity at the time was seen as a major improvement.

[Bernice Loui]

All the folks whom worked with AA spoken to told that AA never did contrast masking. There are no examples of contrast masked prints made by AA that I'm aware of. In the case of this particular story, "TH" was a very, very, very GOOD color printer he made prints in every available color technology available back then including dye transfer. This is where his excellent skills at contrast masking came from. Came time to do this project for one of the major SF museums, he simply applied his skills at contrast masking to make the needed prints. This was the color lab in SF that had the Durst 184 head installed into converted elevator shaft to make GIANT prints.

Worked out really, really well. The effort was to replicate what the original AA prints would be except in a MUCH larger size. AA was long gone when this project was in process.

One thing I've come to understand from doing many many prints, it is a speciality skill that is difficult to learn by theory alone as the theory is the basic beginning of how to make a print, but can NEVER produce an emotionally expressive print by theory alone. That demands a LOT more from the print maker than theoretical knowledge.


Bernice



Bernice, Ansel never seemed to get a handle on masking, so it's interesting that the SF lab which printed some of his negatives used it. It was already routine in color printing, and it's for sake of color work that I got proficient at it, then merely transposed those skills to part of my black and white tool kit. It's those very contracted-out images, the most complete collection of AA's murals ever assembled up to that point at least, that I shared a public exhibition with right after his death, so got to examine them quite well. It is my understanding that he was on hand to at least supervise the printing, even though technicians handled the rest. The feel of those images in big size is quite different from say, 8x10 neg up to 20X24 print. They're a lot softer and more poetic, and just wouldn't hold up well at higher contrast and his usual colder tones because the original negs are pretty grainy and not all that sharp by modern standards at least. But I was strictly color printing at that point in time, highly detailed Ciba prints, and it made an interesting complement.

[Pere Casals]

No, it sounds pretty much correct for negatives of that period. Before the advent of significantly more advanced controlled crystal growth techniques in the 1950's (graded iodide with high monodispersity) & commensurate sensitising methods & use of acutance dyes, together with the advent of thinner multilayer constructions, most films of reasonable speed were nowhere near as crisp & sharp as we might assume today. Polydispersity gave reasonable latitude at the cost of various other problems & the move to monodispersity at the time was seen as a major improvement.

Interneg, probably you are not much aware of historic evolution of film resolving power, 1940 Kodak Super-XX was resolving 45 lp/mm at 1:30 contrast, what would be around 2286ppi, so a drum scan at 2000dpi of a 8x10" negative would not take all information there.

https://3.bp.blogspot.com/-aqxCduzv-iY/VvfjHcoYaRI/AAAAAAAABks/fdbLbF8iI_I75BatFCUYcGmF1ZIvNPCSA/s1600/resolution.jpg

http://videopreservation.conservation-us.org/library/estimating_historic_image_resolution_v9.pdf
http://hubicka.blogspot.com/2016/03/resolution-of-historical-photographs-in.html

For the record:
https://web.archive.org/web/20181008120708/http://videopreservation.conservation-us.org/library/estimating_historic_image_resolution_v9.pdf
https://web.archive.org/web/20181224120201/http://hubicka.blogspot.com/2016/03/resolution-of-historical-photographs-in.html



There is some debate about the exact numbers, but a negative of the 1940's has to deliver a 1.5m print that would be perfectly sharp at reading distance, and possibly it would be perfect by 2m.


Here you have a 1885 shot, the crop is 4.5x5.5mm on the glass plate:

https://2.bp.blogspot.com/-mJ5lJ1EOVR4/VvbJ7v4YoUI/AAAAAAAABjw/f62O9D8zm_oFpLt3lFEN2Dx4a3eFOxNwg/s1600/zoom.jpg

By 1885 5x7" format was outersolving what today can do a $48k Hasselblad H6D-400c, Phase One IQ3, etc...

I'd say that AA's 8x10" negatives are not a joke !

In any case, a 1940 8x10" negative is to outresolve the best 4x5" you can make today.

[interneg]

Pere, those numbers are for understanding the potential useful sweet spot of resolution in certain circumstances, they do not tell you the RMS grain, or show the point at which the emulsion drops below 100% MTF response. It is those factors & a range of other requirements that define far more usefully how grainlessly & sharply a material will resolve. Having optically printed & scanned materials of that era, they do resolve pretty well, but above 2.5-4x, the grain does show & the acutance is poorer. Have you ever seen anything shot or separated on Super-XX? Let's just say that if you've seen a big dye transfer up close you'd know how much grain it delivered.

With today's materials, making an essentially technically competent 2-4x enlargement from 4x5 or bigger is really pretty easy. If it isn't, there's something fundamentally wrong with the most basic parts of your process. Making a truly excellent print is slightly harder & that's where extra techniques can come in if you want/ need to bend specific materials to a particular aesthetic.

[Pere Casals]

Interneg, some have inspected 16x20" AA prints with a magnifier and judged that the negative was poor. With a regular enlarger lens you can make a nice 2X print, but with the magnifier on the print one cannot know how good the negative was because a regular enlarger lens is bad for 2X, it still makes a sharp print for the eye, but it cannot craft the negative quality on the print, for that you need a Rodagon R type lens or the like.

IMHO those judging AA's negatives with only having seen prints cannot tell how good the negatives are.


Say that AA was crafting only 25 lp/mm on the 8x10 negative, this would allow an excellent 1.5m atonishing print. For the SXX grain AA used diffuser enlarges, so the problem was minimized.

[Drew Wiley]

Where on earth do you come up with this stuff, Pere? At least you have a healthy imagination.

[Pere Casals]

Where on earth do you come up with this stuff, Pere? At least you have a healthy imagination.

Drew, my guess is that most AA's 8x10" negatives are insanely sharp, with IQ more than enough to make 1m or 2m perfect prints, this is easy to figure, no imagination required.

We know what glasses he used, the films he used and also we know the fact that he was able to focus a view camera.

Have you any doubt that AA's 8x10" negatives had to be at least beyond 25 Lp/mm ?

[Drew Wiley]

Ha! It depends on what you mean by sharp. When AA was already old and well past most of his shooting career, Kodak's "fine grain" film classification included Super-XX and Tri-X. Combine that with his modern developer choice of HC-110, and you end up with what we'd probably term Buckshot today. Wooden film holders, older lenses, and so forth. I personally have no doubt about what quite a number of AA's most famous view camera shots look like 2m wide because I've seen em; and it's generally more like 25Lp/cm (not mm) at the very best - most were a lot fuzzier than that enlarged much more than 3X, and that was when a better equipped pro lab did the enlargements, and not himself. Some of his still older works looks like buckshot even in contact print version. Of course, he also used a Hassie with very fined grained films later on, but his 2-1/4 work wasn't generally enlarged more than to 16X20 print size. By comparison, Bradford Washburn used a big precision aerial camera either from a plane or on ground for infinity focus work and got negatives capable of significant enlargement. My own big prints were nowhere near as sharp as I can make them today, and when I had them side by side with AA's, alternating, people would always walk right up to mine to take in all the detail, while they had to back off at least 8 ft from Ansel's to get an impression of detail. I watched them do it! That's why in his famous how-do book series, in the Negative, he recommended making large prints softer, warmer, and on lower contrast paper - that's the strategy he HAD to use to make his own shots look good big. They had an entirely different feel to them than his work seen in smaller prints or in books - poetic, but not precise or even particularly dramatic. Not his fault. Cameras, lenses, and films have dramatically improved, and our kit of available options in the darkroom has gotten much better, thanks in part to him giving us a boost from his own learning curve in the first place. But his personal darkroom was primitive in comparison to commercial ones of the times.

[interneg]

Pere, you're assuming he was using Plato-pan, rather than the Super-XX, Portrait Pan or Isopan etc he and many others used. You're also assuming that there are not many many examples of those self same films, no less competently exposed & processed which clearly show their inherent shortcomings compared to the following generations of emulsions in terms of grain & acutance. If you've ever worked with negatives from those eras you will very quickly see the difference between a fairly simple single-run polydisperse emulsion & the much more complex monodisperse multijet run-salt emulsions of the 50's onwards

This is not about Adam's technical abilities, but rather the fundamental behaviour of the films he used in the peak period of his creative career. And that's before we consider the interplay with the paper emulsions which changed just as drastically in the same time interval. Remember too that most of these prints were not envisioned as XXL murals at the time the negative was exposed, but more usually as enlargments up to the 14x18" range, possibly heading towards 20x24" at most, or sometimes merely just an 8x10" contact print.

You can make more than competent mural prints off these films, it's just that more modern film emulsions do it more easily & better from a technical, if not emotional standpoint. Side by side you would think the more modern emulsion noticeably sharper & usually with less obtrusive grain.

[Drew Wiley]

Don't get me wrong - Super-XX was a wonderful film in terms of holding an extremely long straight line - better than anything available today; in terms of development flexibility in contrast; in having a thick emulsion capable of certain development tricks no longer realistic. But you could see the grain even in a contact print. But it wasn't just that - lots of the cameras and lenses AA used, at least up to mid-career, certainly weren't as precise as what most of us would want today. It was a different era.

[interneg]

Drew - I'd agree, it says a lot about how good it was as a separation film that Super-XX lasted far beyond any reasonable lifespan & the specific behaviour of its structure in those colour critical applications seems to have been a large part of this.

[Pere Casals]

Pere, you're assuming he was using Plato-pan, rather than the Super-XX, Portrait Pan or Isopan

interneg, I'm assuming 1940 Super-XX : 45 Lp/mm

"Film resolution protocol based on Kodak’s 1940-56 resolution procedure: “30:1 contrast” target, between the black and white line pairs; printed as l/mm, but is actually lp/mm"

Page 15: http://videopreservation.conservation-us.org/library/estimating_historic_image_resolution_v9.pdf

[Drew Wiley]

(Slightly off topic): The problem with Super-XX and similar 200 films was that the blue color separation could not be developed to the same gamma level as the red and green separations. That meant the difference had to be made up by developing the subsequent matrice film itself, from the blue separation, to a higher gamma - one of the clumsier steps in the whole operation. When TMax was engineered, they actually had it in mind as a replacement for separation negative use, among other things. And remarkably, not only are all three separations capable of being developed to equal gamma, but even in the same batch - all three in the same tray for the same amount of time! That's a huge convenience. But the right hand at Kodak didn't tell the left hand what they were doing, and it seems dye transfer was already nearing the chopping block. But I'll leave that story to insiders, since I've heard it mostly from those who got burned by Kodak's double-talk promising something, then yanking it away at the last minute. I won't go into details technically. I've been delayed getting back to more learning curve of DT printing because I'm tied up getting arguably far better color results by other methods. But I am tempted, just for fun or perhaps self-torture, to take a few sets of separation negs I've already made on TMX and sequentially print them in register onto RA4 paper.

[Drew Wiley]

Pere - technical lab results for diagnostic purposes are one thing, real-world results using less than ideal equipment and ordinary developers, another. Super-XX and its close cousin, Color Separation Film, were even used to make older step tablets. I can see the grain on one of those with my naked eye. I've shot and printed Super-XX sheet film, and have a number of prints my brother made from Super-XX, using a 4X5 Master Technika, which was certainly a more precise camera for its era than wooden view cameras. I've seen lot of dye transfer prints made from Super-XX separations. Visible grain and acutance are related but not synonymous topics. And visible grain isn't necessarily bad. But I can enlarge a 6x7 or 6x9 roll film image from modern fine-grained film and make a more detailed sharper print on 16X20 paper than I could have made with the combination of 8x10 Super-XX film and the cameras and lenses of its own era. AA's strength wasn't his equipment or technical ability, but his instinct for perceiving the subtleties of natural light and his determination to somehow communicate that in print form.

[Pere Casals]

more precise camera for its era than wooden view cameras.

Drew, when you stop to f/32 for your 8x10 shots you don't have a much better Image Quality than in 1950 shots. TMX is better, but diffraction limit is 50lp/mm at f/32, this is contrast extintion, so 0% MTF, so by 25lp/mm you will have only a fraction of the possible modulation transmission.


With the apertures AA used (as he explained ) even with a wooden camera you can stop to have perfectly sharp negatives, in regular scenes you may have more blur from the DOF management in the scene than from any potential missalignment from the wood.



1) inspected with a magnifier, a 16x20 print won't show what's in the negative, because at x2 regular enlarger lenses won't do it.

2) instead a large print potentially was made with the enlarger lens wide open, far from peak performance, and with reduced DOF. You cannot judge the AA negatives from prints he did not even make.


After inspecting the AA's 8x10" negatives with an x40 magnifier we would be able to say if Mr. Adams blurred his negatives or not. IMHO, what's clear is that by 1940 8x10" negatives had an insane amount of Image Quality.


See how that 1885 image crop looks in your monitor at x60 enlargement (it is a 4.5x5.5mm crop in the plate), a 8x10 negative enlarged x60 would be a 15m print.

https://www.largeformatphotography.info/forum/showthread.php?152947-Proof-to-Print-the-contrast-difference&p=1506925&viewfull=1#post1506925

[Drew Wiley]

Pere- Don't tell me what works and what doesn't. You're all theory, and often incorrect theory. I never ever think in terms of lp/mm or pixel equivalents, or assess such issues with a calculator, much less on a monitor screen! But you can step up to many of my prints and need an actual loupe to appreciate all the detail, even on big prints, at least where tight focus was intended to bring your eye. When I was younger doing archaeological and geological research which included mapmaking, I often used on 1930's and 1940's aerial photographs. These were very precisely made in sequence so that one could view any pair side by side with a stereoscope and view the combined image in 3d. Nothing on Google Earth today is even remotely as good in allowing one to detect detail. It can be eye-fatiguing, but it's how many battles were won in WWII using exceptional surveillance photo technique. Probably none of us could come up with such precise results with our own films in our own view cameras. But these were precise Govt and military applications using big expensive automated cameras, where rolls of aerial film were tightly tensioned for precise plane of focus, which were always set at infinity and ideal aperture. But if good ole Ansel had used f/32 in an 8x10 exposure, film sag itself would have degraded sharpness in parts of that image; if he went to f/64 and beyond, the effects of diffraction began setting in. What he thought was a state of the art enlarging lens is what I'd classify as junk today. You're telling me what is "supposed" to be there, when I've seen with my own eyes what ISN'T there?? You are really getting on the borderline of sheer BS, Pere. You're an intelligent person fun to discuss things with, and I'm just truly hoping that after some more time in a real darkroom you'll gain a better appreciation for what's really involved. All these mathematical analogues are getting pretty monotonous. There's more to science than just a postulate; you actually need to test ideas!

[Pere Casals]

and often incorrect theory. I never ever think in terms of lp/mm or pixel equivalents

Drew, at least next theory is pretty right: if with your best modern lens/film today you shot at f/32 then you won't get a better 8x10" negative (image quality) than AA was able in 1950 with the resources he used.

This is quite straight to explain, diffaction limit, you have contrast extintion by 50lp/mm, and probably you will have 50%MTF by 25 lp/mm. Measure it if you don't belive it.




I never ever think in terms of lp/mm or pixel equivalents

OK, but in this case just inspect AA's negatives with an strong magnifier before stating that they are blurred.

Of course he made some some "blurred" negatives, a remarkable one is "Monolith, Face of Half Dome", but the infame Adon glass he had can be enterely blamed. He did not take all shots with that Adon ! :) He also treasured many fine lenses...

[Vaughn]

Hey you two -- get a room!:cool:

[interneg]

Drew, at least next theory is pretty right: if with your best modern lens/film today you shot at f/32 then you won't get a better 8x10" negative (image quality) than AA was able in 1950 with the resources he used.

This is quite straight to explain, diffaction limit, you have contrast extintion by 50lp/mm, and probably you will have 50%MTF by 25 lp/mm. Measure it if you don't belive it.





OK, but in this case just inspect AA's negatives with an strong magnifier before stating that they are blurred.

Of course he made some some "blurred" negatives, a remarkable one is "Monolith, Face of Half Dome", but the infame Adon glass he had can be enterely blamed. He did not take all shots with that Adon ! :) He also treasured many fine lenses...

I'd suggest that you do some serious learning & understanding about how adjacency effects work & are exploited by modern emulsions compared to those of the 50's or earlier, especially in the sub 20 lp/mm range, before you dig this crater of misunderstanding any deeper. For example, look at where the MTF response of TMax 400 drops below 100% and compare to Fomapan 400 - it explains very clearly why one of these films is perceptibly sharper - and note too which one delivers sufficient adjacency effects to deliver a 100%+ MTF response in large object resolution. And that's before looking at the grain structures & means of growth & control thereof. Old emulsions may give very beautiful tonality, but they are rarely super sharp or particularly fine grained for their speed ratings.

[Pere Casals]

I'd suggest that you do some serious learning & understanding about how adjacency effects work & are exploited by modern emulsions compared to those of the 50's or earlier, especially in the sub 20 lp/mm range, before you dig this crater of misunderstanding any deeper. Look at where the MTF response of TMax 400 drops below 100% and compare to Fomapan 400 - it explains very clearly why one of these films is perceptibly sharper. And that's before looking at the grain structures & means of growth & control thereof. Old emulsions may give very beautiful tonality, but they are rarely super sharp or particularly fine grained for their speed ratings.

Interneg, common adjacency effects are mostly relevant for 35mm format... here we speak about LF.


Regarding MTF graphs in the datasheets, the TMY graph is for shure (not specified, but reaching 200c/mm) made with a TOC 1:1000 contrast, while for Foma 100 the target contrast is not specified, but for sure is not at 1:1000, it looks to me something around 1:30.

Look, if a film is perceptibly sharper this is well seen in 35mm or even in MF, but by 8x10 you will notice that much less. You have other limiting factors, lenses usually resolve less, aperture usually provocates more diffraction, and DOF is more challenging.

At the end we know that 1940 Super-XX is 45lp/mm able at 1:30 contrast, that 1940 lenses were matching that resolution, and that today many LF photographers stop to f/32 provocating a diffraction that limits performance to the 1940-50 levels.


hmmmm, haven't you seen that 1885 image ? The crop shows in your monitor like in a 16m print from 8x10"... 16m! and year 1885 ! isn't that enough ?

https://www.largeformatphotography.info/forum/showthread.php?152947-Proof-to-Print-the-contrast-difference&p=1506925&viewfull=1#post1506925

[Drew Wiley]

Vaughn, get your fur clipped. You're in big trouble if they permit Grizzly hunting in the lower 48 once again. Pere - you ignore the tremendous depth-of-field constraints and limited options available to 8x10 photographers in many landscape situations. And honestly, how many of AA's negatives and prints have YOU actually seen? Any Super-XX negs at all ???? You're running on fumes. Go ahead, get a 1940's wooden camera, with holders and lenses of the same vintage, and let's see what YOU can do even with modern film. Then we'll talk some more. And yes, my own 8x10 shots tend to be WAY WAY more detailed than anything AA ever got; even my 4x5 shots are! And I'm not surmising. They've been side to side in a significant public exhibition. And film and lenses have gotten even better since then. But overall, there's way too much fuss on this subject here. Just get out and enjoy taking pictures, then printing them.

[Drew Wiley]

Let me phrase it a little differently, Pere. Why do people imagine AA was the epitome of darkroom skills, or a consummate craftsman, just because he made a number of iconic images? He was a competent black and white commercial photographer, appropriately equipped for that profession in that era, who deserves his place in history for his significant role in the American conservation movement, his involvement in promoting photography as a fine art, and the compelling content of his images. He knew how to get the job done in a darkroom, but was nowhere near the skill and equipment level of any serious color lab of the era. He certainly wasn't a machinist. Some of his classic shots were taken with cameras that would seem downright funky today. He was distracted organizing and leading huge Sierra Club outings, giving photo lectures on the spot, digging gear out of a mule pack, and so forth. He had to support a family with what he called "nuts n bolts" commercial work. He wasn't obsessed with sharpness or big enlargements. It was the choreography of the images that counted. You seem to be buying into a kind of mythology about him. Just because SOME of his prints are highly collectable and have become iconic does not mean he was the master of all things photographic. Quite to the contrary.

[Vaughn]

Vaughn, get your fur clipped. You're in big trouble if they permit Grizzly hunting in the lower 48 once again...
Well, I am seriously considering trimming the beard down a bit for summer...:cool:

[Pere Casals]

Go ahead, get a 1940's wooden camera, with holders and lenses of the same vintage, and let's see what YOU can do even with modern film.

Drew, sorry for the reiteration, but this is a 4.5x5.5mm crop enlarged x60 in your monitor, from a 1885 5x7" plate (a wooden camera ?), a x60 of a 8x10" negative would have 15m.

https://2.bp.blogspot.com/-mJ5lJ1EOVR4/VvbJ7v4YoUI/AAAAAAAABjw/f62O9D8zm_oFpLt3lFEN2Dx4a3eFOxNwg/s1600/zoom.jpg



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So to me it's wrong your statement that AA master could not make sharp negatives becuase of the era's gear. We may ask John Sexton, probably he could see several AA's negatives, I guess.

[interneg]

common adjacency effects are mostly relevant for 35mm format... here we speak about LF.

Nope. Wrong. You've got it backwards. Edge effects matter more in larger formats, in smaller formats, contrast substitutes for the edge effects as they bunch closer together. This is intentionally exploited in modern films.



Regarding MTF graphs in the datasheets, the TMY graph is for shure (not specified, but reaching 200c/mm) made with a TOC 1:1000 contrast, while for Foma 100 the target contrast is not specified, but for sure is not at 1:1000, it looks to me something around 1:30.

Again, wrong. Those MTF charts are comparable, they are done by rather more complex analytical means than photographing a simple test chart on a wall - and the max resolution statements are irrelevant to the matter under discussion here. That you don't like the conclusions from the graphs is a different matter entirely.


At the end we know that 1940 Super-XX is 45lp/mm able at 1:30 contrast, that 1940 lenses were matching that resolution, and that today many LF photographers stop to f/32 provocating a diffraction that limits performance to the 1940-50 levels.


All it tells us is that under conditions roughly equivalent to the flattest contrast a photographer might encounter, that was the best resolution they might get, not how grainy or sharp the film was.

And as for the glass plate: it's not difficult to take a neg from the 20's or 30's - or even the 1890's - & make a very big print from it & you'd think it was remarkably detailed. But if you then saw a print of similar enlargement from a similar negative format current production film alongside it, the difference would be really quite obvious.

[Drew Wiley]

Vaughn, I'm trimming everything I can. Put on a couple of inches of girth when I had to stop using a full pack for a couple of months getting over my shoulder bursitis. Did plenty of hiking, but not with enough weight. But I should have plenty of time to get back in full shape before the next serious backpack trip, at least to the extent someone my age can pretend to be in shape! Don't you just shed in summer like other furry creatures? My cats sure do. Gotta change out of my house clothes every time I walk into the lab lest I carry kitty hairs with me.

[Drew Wiley]

Pere - glass plates were still being coated for astronomical work up to maybe the 1980's, even in TMax 100 emulsion. Why? They're FLAT, dimensonally stable, and were made for use in massive extremely precise machines - nothing in common with garden variety old wood cameras and their often-warped holders with sagging sheet film in them, like AA used most of his career. But why am I wasting my time responding to you? You are 100% guessing about everything. I'm not. I've even duplicated and printed all kinds of antique photos, have a big collection of em. I've got a big pile of my brother's Super-XX negs in the room right behind me, as well as prints made from them. Please, please burn your calculator and your monitor, and maybe we can talk about actual photography.

[Vaughn]

Vaughn, I'm trimming everything I can. Put on a couple of inches of girth when I had to stop using a full pack for a couple of months getting over my shoulder bursitis...
Bummer about the bursitis -- my last bout of that was ten years ago. What cured it was helping out with my boys' little league practices -- gentle warm-up throwing (right shoulder). The easy repetitive movement was the key. YMMD. The same with my poor knees -- bicycle riding keeps the pain away. Actually hiking with a pack helps too, strange as that may be.

[Pere Casals]

Nope. Wrong. You've got it backwards. Edge effects matter more in larger formats, in smaller formats, contrast substitutes for the edge effects as they bunch closer together. This is intentionally exploited in modern films.

interneg, your statement is LOL. Even it's difficult to notice edge effects in 35mm film, with regular development.

Of course an stand agitation, with very diluted developer (1:1:400 pyrocat) and several hours of development may deliver edge effects with sheets, but this is not a capability of modern films, it's stand processing, "power of process".




Again, wrong. Those MTF charts are comparable, they are done by rather more complex analytical means than photographing a simple test chart on a wall - and the max resolution statements are irrelevant to the matter under discussion here. That you don't like the conclusions from the graphs is a different matter entirely.


I reiterate, the contrast level of the test is critical, TMX only resolves 40 lp/mm at low contrast, as the Foma graph has unknown contrast in the target we simply cannot compare. It is surprising you don't realize that :)




And as for the glass plate: it's not difficult to take a neg from the 20's or 30's - or even the 1890's - & make a very big print from it & you'd think it was remarkably detailed. But if you then saw a print of similar enlargement from a similar negative format current production film alongside it, the difference would be really quite obvious.

Well, just reduce the x60 enlargemet to x6, you will perfectly see that this 1885 image is perfectly suitable for that elargement level, still a 8x10 would deliver a pefectly sharp 1.5m print, or beyond. And that was in 1885, so it's LOL that 1940 AA negatives have to be blurred. Single AA blurred negatives are those taken with the crappy Adon zoom lens.

Look at the 4.5x5.5mm crop... it's obvious !!! :)

[Drew Wiley]

Vaughn - Nothing cures my bursitis faster than swimming; but we won't be back in Maui for awhile, and am not keen on public swimming pools. The water was safer in the cattle ponds and creeks I swam in as a kid. One can get a steroid shot for bursitis that acts quickly, but allegedly that only works so many times, so I'd prefer to save it for emergencies. My stomach can't handle anti-inflammatories like Advil. Tylenol is OK. Last year I just went ahead and backpacked with bursitis. My clavicle could handle the weight. The real problem was driving there and back with my arm all cramped up against the truck door. That was misery. But nothing gives me old age aches and pains quite like some of these threads. Guess I'm addicted to them, at least until the evening news stops talking about politics; that's even worse. Some lovely PBS documentaries later in the evening, including one on the Amazon last night, beautifully filmed. B&W filmage of my Dad popped up in a PBS documentary a couple year ago about the Central Valley water wars, which began with the Friant-Kern Canal my father supervised. Had my ole art agent featured in another PBS documentary just a year ago. But when the self-help guru programs go on, I wanna throw a boot at the TV. I grab a book, a cat jumps on my lap, and try to get some calm before my wife wakes up from her evening nap (hectic medical career).

[interneg]

interneg, your statement is LOL. Even it's difficult to notice edge effects in 35mm film, with regular development.

Sharpness in 35mm is more reliant on contrast from the higher density inherent to finer line resolution behaviour & in LF by edge sharpness. Thus getting 50% MTF response or better at as high resolution as possible matters more for smaller formats, getting a 100%+ response in the 10-20 lp/mm will strengthen edge effects for larger formats. Older films exploited this much more poorly or not at all. Thus they are less perceptibly crisp when enlarged to a big size. And that's before considering interimage effects, antihalation etc.



I reiterate, the contrast level of the test is critical, TMX only resolves 40 lp/mm at low contrast, as the Foma graph has unknown contrast in the target we simply cannot compare. It is surprising you don't realize that :)

All you're showing is you can't read an MTF test to save yourself. It's not about the other resolution specifications that don't relate to perceptible sharpness. If properly performed, MTF tests should be usefully comparable.

Just to prove that you're reading the graphs, tell us at what lp/mm TMax 400 drops below 100% response & where it delivers 50%. Then do the same for Fomapan 400. Those numbers tell us much more about the relative sharpness changes over the decades. The difference between these two and the single run emulsions of the 50's and earlier is just as dramatic. The old emulsions are not unsharp, or particularly poor resolving, but compared to the materials that came after they do not have the same intensity of sharpness or finer, more sensitive grain structures.

As Drew said, you are in desperate need of gaining actual experience with the materials you spend so much time & urgency telling us about.

[Pere Casals]

If properly performed, MTF tests should be usefully comparable.

Nope. Beyond properly performed, contrast of the target has to match in the tests you compare, it's surprising that you don't realize that.





Just to prove that you're reading the graphs, tell us at what lp/mm TMax 400 drops below 100% response & where it delivers 50%.

192981

In the TMX MTF for the 1000:1 contrast I add the MTF for a low contrast target, datasheet (page 25) says that with 1:1.6 contrast target you have extintion by 40lp/mm, so the rest can be interpolated.


You should realize that 1000:1 contrast is 10 stops, in practice you will never find that contrast on film because the lens is not able to deliver say 40 line pairs per mm with the white lines 10 stops brighter than the black lines, such a contrast in fine detail is not feasible by far, only a silhouette in a insane backlight may deliver 10 stops contrast, but the lens may deliver 1:2 contrast at 30lp/mm in most cases. Fine textures are usually more close to 1.6:1 contrast on film.


Interneg, you should be aware of it...

TMX (and TMY) has layer of very small cubic grains under the main emulsion that works in the extreme highlights to deliver a linear response there.

At 1000:1 contrast you mainly evaluate that layer rather than the main emulsion. Kodak datasheets are very good (says TOC 1.6:1 and TOC 1000:1), but in this case that graph is a bit missleading because performance in the 1000:1 contrast has little importance as usually is not found in pictorial work textures. For a photographer with technical curiosity a (say) 1:4 contrast MTF graph is what it would be useful.

[Bill Burk]

Lots to mull over. Not only flare but larger prints need different contrast than small prints to look good.
So I just “proof” on 11x14. If it looks good I don’t have to figure out what to adjust for the final print...

Because the final print is in my hands.

[interneg]

Pere, you're attempting to conflate several different sets of tests. The MTF tests, the resolution tests & the RMS grain are determined in quite specific ways, such that they should be usefully comparable between manufacturers. If you had used the films I referred to above to any extent at all, and especially across a range of formats, you would see that the MTF charts in the respective data sheets pretty accurately represent the films' sharpness characteristics. As has been said multiple times in multiple threads, you quite clearly have very minimal/ facile experience with the materials you so desperately want to lecture us about.

The construction of TMY-II is intended to offer the benefits of polydisperse emulsions (good latitude) and the benefits of highly controlled grain growth emulsions with precisely placed iodide (sharpness, speed, nice straight curves etc) and full utilisation of sensitising technology to maximise acutance etc. Ilford are doing similar things with the Delta films, possibly involving epitaxy.

[Pere Casals]

The MTF tests, the resolution tests & the RMS grain are determined in quite specific ways, such that they should be usefully comparable between manufacturers.

Interneg... Interneg...

Imagine that Rodenstock releases the MTF graphs at 30 lp/mm only and Scheneider at 5 lp/mm only. Sure that the Scheneider curve would be nicer, but this don't tells what lens is better or how much better.

With film MTF charts we it happens something like that, for target contrast 1.6:1, 30:1 or 1000:1 a film delivers very different curves, so if contrast is not specified for the graphs then you cannot compare at all. Let me reiterate how different the TMX MTF curves would be with high and low contrast:

193007

If you are not able to understand that I cannot do anything else, but you should realize that target contrast is essential, TMX has extintion at 200lp/mm or 40 lp/mm depending on contrast, this fact should be enough for you to realize that it's essential, isn't it?




As has been said multiple times in multiple threads, you quite clearly have very minimal/ facile experience with the materials you so desperately want to lecture us about.

Sorry, I don't repply to such kind of comments.

[ic-racer]

After modifying my E6 5x7 Omega diffusion enlarger's light source to LEDs, I made a number of tests with Stouffer step wedge to check how it performed with Ilford under-lens filters. I was always wondering about a difference in contrast between a contact and an enlargement, that I'd read about; so while doing these tests I first projected the step wedge for a Gr2 print (masking the wedge as much as possible in the carrier to minimize flare), then made a contact print of the wedge with same Gr2 filter and unchanged enlarger height). Checking the two results with a reflection densitometer showed a definite contrast difference - results of the two prints are attached. But I suppose the inherent flare from the enlarger lens/bellows in the projection print could explain the difference - I may never know for sure. BTW, the two curves have been adjusted to intersect at a .09 density (Zone VIII) in order to show the difference in slopes more easily.
If it helps in reading the attachment, notice that it shows at RLE 1.7, for example, the difference in the blacks is substantial; density of 1.45 represents Zone III + 1/3 in the projection vs Zone II in the contact - a difference of at least one zone) - even though the highlights are unchanged. These measurements were done on DRY prints, so the effects of dry down are included.

Nice, thanks for sharing. I see 65 posts after yours no one else could figure it out.

[Drew Wiley]

All of that is personal enlarger specific, and even then can differ depending on several variables. When in doubt, test. But making generalizations is of little practical value. It's good to see the step wedge was masked off before measurement. But some distinct difference in contrast between a contact print and a projected one if inevitable, though the projection should be 1:1 if you are truly trying to compare apples to apples; and in that case, it still wouldn't because you'd need an enlarger lens realistic for 1:1 used at a relatively long bellows extension. I just don't worry about it. VC paper makes life easy.

[Jerry Bodine]

Nice, thanks for sharing. I see 65 posts after yours no one else could figure it out.

You're welcome, ic. Large post-counts are often a result of pissing contests.

[Pere Casals]

pissing contests.

This should be debated with calm, probably we see too many off-topics, sometimes with too much personal involvement.

..but there are other ways to express what you want to say without using that kind of wording. Pissing, defecating, spitting, vomiting, etc wording... well...

[Tin Can]

Marking territory...

[interneg]

This thread would not have gone on so long if one particular person had not spent so much time conflating and misreading fairly basic data and empirical knowledge & then urgently trying to deflect wildly with an array of googled clichés when challenged.

That he seems intent on apparently not understanding the difference between how the high and low contrast resolutions of a film are measured (bar charts of specified contrast) and MTF (usually a spoke chart that goes to extinction at 500 cyc/mm) - quite apart from lens charts showing MTF at specified cyc/mm relative to lens imaging circle not being relevant at all to the MTF performance of film which shouldn't have a different performance at the centre or edge under test conditions!

[Pere Casals]

interneg, do you understand that the MTF graph for a film is completely different if test is performed at TOC 1000:1 or TOC 30:1 ?

at what TOC is the Foma chart done, do you know it ?

[Jerry Bodine]

All of that is personal enlarger specific, and even then can differ depending on several variables. When in doubt, test. But making generalizations is of little practical value. It's good to see the step wedge was masked off before measurement. But some distinct difference in contrast between a contact print and a projected one if inevitable, though the projection should be 1:1 if you are truly trying to compare apples to apples; and in that case, it still wouldn't because you'd need an enlarger lens realistic for 1:1 used at a relatively long bellows extension. I just don't worry about it. VC paper makes life easy.

Thanks, Drew, for this excellent on-topic summary, which I felt should be the best place to end this discussion, but it seems that is not the way of free speech. I hadn't thought about the fact that flare itself is a variable, dependent upon the enlarger's bellows extension.

[Drew Wiley]

If one is paranoid about bellows flare there are ways to mitigate it. But I'm hesitant to recommend ordinary black flock lining lest it open a whole new can of worms. It traps lint. The better kind is vinyl-backed, and vinyl outgasses and smudges things. Some enlargers run hot and it might catch fire. But simply more pleats in the path of a well designed bellows for the anticipated usage are a big help. Most of us don't do 1:1 work with our enlargers. I sometimes do approx 1:2 for 8x10 internegs or dupes from 4x5 originals, but have already minimized flare and have the instrumentation to closely measure it. But contact prints have their special look for more reasons than just contrast distinction, which is a way more involved topic sure to raise some fireworks. And today, I think there will already be far too much fireworks noise. Firetrucks were already zooming around the neighborhood yesterday handling early fireworks incidents. Glad a neighbor finally mowed their overgrown front yard this morning. Hope your day goes well, Jerry.

[interneg]

interneg, do you understand that the MTF graph for a film is completely different if test is performed at TOC 1000:1 or TOC 30:1 ?

at what TOC is the Foma chart done, do you know it ?

What the MTF records is the percentage of the object's contrast at a given frequency that can be recorded by (in this case) the film being tested. Within reason, the object contrast should not be a factor, because what is being tested is the reproduction of that contrast relative to the theoretical model of 100% at 0 cyc/mm and 0% at the diffraction limit. A Siemens star or similar is a likely test object & if you get wonky results, it's probably because your target is out of focus. The 1951 style bar charts are used for resolution tests at specified contrasts, not MTF.

[Pere Casals]

Within reason, the object contrast should not be a factor, because what is being tested is the reproduction of that contrast relative to the theoretical model

Interneg, while this is a cleaver reasoning it cannot be applied. This is not only optics, for film you have the non linear response of photochemistry in the middle.

IIRC TMax films have two emulsion layers, under the main one you have a very low ISO layer with ortho cubic crystals that only works in the shoulder, at 1000:1 you evaluate that layer over some "noise" from the main emulsion.

If the main emulsion was not there then the low ISO cubic emulsion (high res) would have even better numbers, just remember that (perhaps comparable) ADOX CMS 20 (monodisperse) delivers 800 Lp/mm at high contrast.




if you get wonky results, it's probably because your target is out of focus.

Its not me, it's Kodak in the TMY datasheet that says that resolving power changes (200lp/mm to 50) with target contrast:

193051

Interneg, this is a fact...



_____________


In "normal" pictorial usage the low ISO cubic layer may not even work, because it's only exposed in the shoulder or where the shoulder should be.

[Drew Wiley]

Hi, Pere. Published results are per specific developers, namely those of the same film mfg brand. Change that, and chart resolution itself changes, esp if a different dev tweak improves acutance expectations, as some do to TMX. So one needs to be specific about the parameters, as you no doubt already know. I print these films so often from multiple formats that their behavior has become second-nature to me.

[interneg]

Interneg, while this is a cleaver reasoning it cannot be applied. This is not only optics, for film you have the non linear response of photochemistry in the middle.

And you don't think this isn't excruciatingly thoroughly tested at emulsion design, layer build-up, test coating, production coating etc, etc by people who have more than a hint of a clue about all this? The MTF charts are a representative snapshot of the behaviour of the full film. And they are & should be comparable. You'd notice very fast if you used the materials whether the MTF charts were correct or not from the relative edge sharpness or otherwise of the film. This does of course depend on the quality of the optical transfer functions of the rest of your imaging chain.



Its not me, it's Kodak in the TMY datasheet that says that resolving power changes (200lp/mm to 50) with target contrast:

Yes, on a resolution test, not an MTF test. Different test, different test targets. The MTF chart is designed to diffraction limit, the resolution charts aren't. If the MTF isn't great, it'll impact on the resolution test by blurring edges to the point the bars on the resolution charts become indistinguishable blocks. Grain also plays a role in this regard too.

[interneg]

Change that, and chart resolution itself changes, esp if a different dev tweak improves acutance expectations, as some do to TMX.

Yes - and quite interesting to see the ways that traditional acutance developers aren't necessarily the best way to exploit engineered-in sharpness enhancers in modern films. Some solvency seems to be necessary for optimal performance between sharpness & grain on the latest emulsions with precisely placed iodide.

[Drew Wiley]

Ironically, in most sheet film applications, TMY400 looks sharper in print than TMX100. It's an acutance issue. The numbers don't tell you everything.

[interneg]

Ironically, in most sheet film applications, TMY400 looks sharper in print than TMX100. It's an acutance issue. The numbers don't tell you everything.

I'd agree with you on both points- and the total overall look/ feel of the film is what matters when choosing which one to use.

[Pere Casals]

Yes, on a resolution test, not an MTF test. Different test, different test targets.

Interneg, what I was pointing is that film modulation transfer is extinguished (0% MTF) at 200 or at 50 lp/mm depending on test contrast, if you remember we were debating that MTF graphs of different films cannot be compared if not knowing the contrast of the test, because depending on the contrast (and exposure) we evaluate the work of a component or other in the emulsion formulation (larger or smaller grain sizes).

Also an interesting test is making contact copies of a USAF 1951 glass slide (better with collimated light) with different exposures. While test contrast would be high, depending on exposure you would find different performance, the contact copies made at -3 stops underexposure would expose only the largest grains and you should see a lower performance than at -/+0 (nominal ISO exposure) or at +3 overexposure.

Sorry if I'm lecturing, but the way we can easily make a low contrast test is making a pre-flash (or post) on the film before (or after) we make the contact copy, also in that lower contrast test we'll find different performance depending on exposure level.

In the kodak TMX/TMY/TMZ graphs (reaching 200lp/mm scale) probably the black lines (in the 200lp/mm target) are underexposed -4 stops while the white lines are overexposed 6 stops. That kodak graph is not useful for pictorial concerns because we cannot place a 200lp/mm texture on film with 10 stops contrast, we don't have the lens nor the subject.

But still kodak shows that 1000:1 graph, I guess that it would make sense for some technical applications, for pictorial usage we never have 10 stops contrast in a texture, by far.

[interneg]

Pere, the MTF test does not particularly care about the contrast of the target - it is looking at what percentage of that target's contrast it reproduces. Look at a Siemens star for an example of the sort of diffraction limited target used. The high and low (and others) contrast resolution targets are not diffraction limited charts, but they test the film for its diffraction limited resolution at a specified contrast (as a consequence of MTF, RMSG etc) to an ISO standard. You are confusing & conflating two measurements. The MTF is a good representation of the film's apparent acutance/ sharpness, and the high/ low contrast resolutions give the potential resolution of the film, which is a direct consequence (in part) of the MTF & RMSG results. In other words, 90 lp/mm at high contrast, an RMSG of 17.5 and an MTF that drops below 100% response at 10 lp/mm is going to seem markedly less sharp than one that delivers 200 lp/mm at high contrast, an RMSG of 10 and has better than 100% MTF response out to 30+lp/mm. Grain plays a role, but turbidity & internal reflections are also significantly responsible for poorer MTF performance - if you have better antihalation, and can better adsorb absorber dyes of highly specific formulation, sharpness can be dramatically improved, allowing much more complex multilayer constructions like the TMax films.

[Pere Casals]

Pere, the MTF test does not particularly care about the contrast of the target

Interneg, this is true for rating lenses, but not for rating film. For film several tests are made at different contrasts/exposures, delivering different graphs. The ISO 6328:2000 norm explains it, section 5.3 tells the optimum-exposure test.

[interneg]

Interneg, this is true for rating lenses, but not for rating film. For film several tests are made at different contrasts/exposures, delivering different graphs. The ISO 6328:2000 norm explains it, section 5.3 tells the optimum-exposure test.

Quote it so that we can see if you are talking about the right test.

6328 is about a tribar resolution target, not MTF, read the first paragraph of the introduction carefully, specifically the first two sentences. It makes clear that your assumptions - that MTF and high/ low contrast measurements are the same thing - are mistaken. MTF influences resolution, not the other way round.

[Pere Casals]

Quote it so that we can see if you are talking about the right test.

6328 is about a tribar resolution target, not MTF, read the first paragraph of the introduction carefully, specifically the first two sentences. It makes clear that your assumptions - that MTF and high/ low contrast measurements are the same thing - are mistaken. MTF influences resolution, not the other way round.


:) :) Interneg...

The only thing I say is that film resolution (and MTF graph) depends a lot on contrast and exposure. (not like lenses)

193067

193068

You were negating that, Post 90:


Pere, the MTF test does not particularly care about the contrast of the target

and what you say is wrong for film rating, it's ridiculous you insist, and also it's ridiculous I insist in demonstrating what's evident and what every film technician knows, so I quit, I won't debate those (sadly off-topic) facts anymore...

In the ISO 6328-2000 introduction and in post #89 you have information if you want it.



Best Regards