Critical Thinking 2 - Normal Negative Density Range - ZS vs Tone Reproduction

[Keith Tapscott.]

For a diffusion light source grade 3 paper LER is 0.88 and for a condenser light source 0.65

https://beefalobill.com/imgs/Contrast Indexes - Kodak.jpg

Thanks Bill. I already have my exposure and development sorted, but I still like to read about the technical side when the subject arises.

 

[Stephen Benskin]

This thread was originally about properly interpreting the results from two methodologies. How a test is interpreted is just as important as making the test, especially if the results are intended to be shared. Tone reproduction, Zone System, and other methods including simple trial and error, all endeavor toward the same goal: to match the scene to the printing material and establish a standard goal or normal. The difference between the various methods mostly has to do with the degree of control, repeatability, and communicating the results. As with most testing, the results will fall within a range. Because the final product of a photograph is subjective there is generally a greater range of acceptability. This has been both a saving grace for practioners and the cause for endless debate.

In the paper, Jones, L.A., and Nelson, C.N., Control of Photographic Printing: Improvement in Terminology and Further Analysis of Results, Journal of the Optical Society of America, V. 38, No. 11, 1948., Jones was evaluating the best approach to objectively determine sensitometrically the paper grade that will consistently produce high quality prints. Jones concluded, “because of the influence of the brightness distribution and subject matter in the scenes photographed, an accurate prediction cannot always be made of the exposure scale (LER) of the paper which will give a first-choice print from a negative of known density scale (DR)… But what other course is there to follow? Either we must make the best of a somewhat imperfect relationship or face the prospect of having no criterion whatever for choosing the paper contrast grade.”

Even though matching the negative DR to the paper LER isn’t a perfect criterion, it is good enough to produce quality images in most situations, or at least with a slight contrast adjustment. Jones also found a few exceptions to the DR / LER criteria, “for the soft papers, the density scales of the negative (DR) should in most cases exceed the sensitometric exposure scale of the paper (LER), whereas, for the hard papers, the density scales of the negatives should in most cases be less than the sensitometric exposure scale of the paper (LER).” So, it's more about determining the middle of an acceptable range than nailing a precise value. As with table 2-4 from the previous post, the "desired density range of a negative usually suitable for each Log Exposure Range or Grade Number" is a range and not a specific value. Grade 2 for a diffusion enlarger is 0.95 - 1.14. Most often the stated LER for a grade of paper is the middle value which in this example is 1.05. If the aim is for an LER of 1.05 then the results most likely will work on a grade 2 paper in practice. However. these values also assume an understanding of what numbers actually represent. The paper LER doesn't refer to the full range of the paper from black to white. Nor does it mean this is the target density range for the negative, but only represents a portion in relation to the subject luminance range.

With that in mind, the following graph excellently illustrates Jones conclusions. The curve is a grade 2 paper curve. The horizontal lines represent the density ranges of negatives that produced first choice prints (best judged quality) when printed on the paper and where the ranges fell on the print. A necessary consideration has to do with the judging parameters. A realistic representative of a scene is different than a dramatic or abstract interpretation. All can be considered excellent in their own right, but fall outside the parameters of the test. For the record, the judges evaluated the photographs as to whether they were a good representative of how the judge believed the scene looked in real life. A realistic representation since this was the goal of the majority of photographs taken.

 

[Bill Burk]

Thanks Stephen!

I wonder if we could have a Nikon "Matrix Metering" type of app which would take a raw scan and recommend grade settings for an enlarger. Probably would have a limited market, so probably won't happen.

I seem to recall it's everywhere, so I don't know who said that there wasn't a way to objectively select paper contrast so take the LER and NDR as suggestions and choose the final paper contrast by trial and error.

Did Jones say something like that?

In my "studies" I was prepared to go into paper matching but short-circuited it when I realized that I already "knew" what grade to use.

 

[Augustus Caesar]

Thanks. I have an old magazine somewhere that says that 35mm films should be exposed and processed to be printed on grade 3 as standard rather than the usually recommended grade 2.

It makes sense because of the higher magnification required for the small negatives. It also covers optimum F/stops to squeeze maximum image quality.

Yes. The "Grade 2 standard" was an artifact of the days of contact printing.

 

[MattKing]

Actually, I would suggest that the papers were designed so that a middle contrast grade - grade 2 - would give the best results with the most common negatives and most common printing methods.
Yes, contact printing was one of those methods, but that contact printing was the type used in "snapshot" type prints provided to the casual photographer - often from much larger than 35mm negs, that often received much more exposure than would be considered optimum now for the vast majority of film photography.
Everything has evolved since then.

 

[Augustus Caesar]

Actually, I would suggest that the papers were designed so that a middle contrast grade - grade 2 - would give the best results with the most common negatives and most common printing methods.

Yes, contact printing was one of those methods, but that contact printing was the type used in "snapshot" type prints provided to the casual photographer - often from much larger than 35mm negs, that often received much more exposure than would be considered optimum now for the vast majority of film photography.
Everything has evolved since then.

Correct. 35mm film requires more delicate development to achieve optimum quality.

 

[Augustus Caesar]

The contrast of paper should have nothing to do with the negative density range. All negatives should be developed the same and printed on the same grade of paper, with minor adjustments in case of under-exposure or bad flare. This will assure that the mid-tones are reproduced at close to 1:1.

Thanks Stephen!

I wonder if we could have a Nikon "Matrix Metering" type of app which would take a raw scan and recommend grade settings for an enlarger. Probably would have a limited market, so probably won't happen.

I seem to recall it's everywhere, so I don't know who said that there wasn't a way to objectively select paper contrast so take the LER and NDR as suggestions and choose the final paper contrast by trial and error.

Did Jones say something like that?

In my "studies" I was prepared to go into paper matching but short-circuited it when I realized that I already "knew" what grade to use.

 

[RalphLambrecht]

No matter how much you think you understand something, any feelings of complacency are shattered when you have to explain it to someone else. They say no one learns more in a classroom than the teacher. And that pretty much sums it up when I was teaching a class and the lesson was on the Zone System. Like many people, I started with the Zone System, but soon I moved onto more scientific versions of sensitometry and tone reproduction.

When it came time to teach, I had to finally face certain concepts that didnt seem to match up between what I learn about sensitometry and what the Zone System was explaining. One of these dilemmas is on how to define a normal negative. The basic idea is to process the negative so that the negative density range will fit onto the papers log exposure range. While sensitometry uses the method that is described in Chucks thread Testing for Relative ISO Range Numbers, the Zone System has a set of density aim values for the negative to fit onto a grade 2 paper.

According to sensitometric and tone reproduction theory, a paper with an LER of 1.05 is considered a grade 2 paper; therefore, a negative with a density range of 1.05 should fit nicely onto the paper.

According to Zone System theory, the negative density range for a grade 2 paper is 1.25 (1.35 0.10). Sensitometric theory says that is the range for a grade 1 paper and not a grade 2 paper.

Obviously one has to be wrong. Since a negative with a density range of 1.25 will be too contrasty for a LER 1.05 grade 2 paper, it must be the Zone Systems approach that is incorrect. Except that in practice, both methods seem to work. Thus the dilemma.

Some people dont seem to have problems not questioning such differences. Personally, I had blown off the Zone System values as coming from a less precise, less sophisticated method. That is until I had to explain it and why it still worked. I had to ask myself how two seemingly dissimilar methods that had different stated aim values could produce similar results.

Theres a good reason for it and an important lesson that should be kept in mind by everyone when testing.

I did both approaching this scientifically and trying t use the plain Zone System. Both worked for me, but I'm seeing you about to make the same fundamental mistake I
made and that is: trying to fit the entire subject brightness range onto the paper. That is indeed possible but rarely desirable, as it will ultimately lead to a battleship-grey print. A good-looking B&W print has some Dmax blacks and some Dmin whites to show the entire palette of greys

 

[Stephen Benskin]

The contrast of paper should have nothing to do with the negative density range. All negatives should be developed the same and printed on the same grade of paper, with minor adjustments in case of under-exposure or bad flare. This will assure that the mid-tones are reproduced at close to 1:1.

I believe you may have misinterpreted the 1956 Kodak publication which appears to have been published in 1952. Could you provide a supporting argument that doesn't rely on that one source? Please include an explanation what the NDR is based upon.

FYI, the mid-tone gradient on the reproduction curve should exceed 1.0. Generally the preferred gradient should be at 1.10-1.12, according to The Theory of the Photographic Process, 3rd edition, Chapter 22, The Theory of Tone Reproduction by C.N. Nelson (co-author of the above paper with Jones).

 

[Stephen Benskin]

I did both approaching this scientifically and trying t use the plain Zone System. Both worked for me, but I'm seeing you about to make the same fundamental mistake I
made and that is: trying to fit the entire subject brightness range onto the paper. That is indeed possible but rarely desirable, as it will ultimately lead to a battleship-grey print. A good-looking B&W print has some Dmax blacks and some Dmin whites to show the entire palette of greys

Hi Ralph,

That is not what that post was about. It was pointing out the Zone System aim of 1.25 and the tone reproduction aim of 1.05 are really the same because the testing procedures are different, but as the resulting gradients are identical, the input to output will be the same, so the resulting aim should also be the same meaning the interpretation of the test results from one of the methods is resulting in misleading conclusions.

The post you quoted is from 2010, so I've long since gone down that road.

Stephen

 

[Bill Burk]

Teacher learns more… that’s true.

ZS 1.25 vs. tone reproduction 1.05 are the same… noted.

Battleship gray when you try to fit a large subject luminance range by reducing development… agreed that’s a bad picture.

But when it comes to developing all film the same, in the words of Stevie Nicks “better leave me alone”. Because I’ve got grade 2 baby and it gives me all the love I need.

 

[Keith Tapscott.]

I’ve got grade 2 baby and it gives me all the love I need.

What I have noticed in the past was that one manufacturers contrast grade can differ from another manufacturer.
For example, I found Kentmere Kenthene paper in grade 2 to be nearer equivalent to Ilfospeed grade 3 when I tried them years ago.

 

[Stephen Benskin]

What I have noticed in the past was that one manufacturers contrast grade can differ from another manufacturer.
For example, I found Kentmere Kenthene paper in grade 2 to be nearer equivalent to Ilfospeed grade 3 when I tried them years ago.

Paper grades are no longer part of the ISO paper standard, but are too established with the public so manufacturers have kept using them. The problem with grade numbers is that they are somewhat arbitrary. Look to the ISOR number. ISOR defines the paper using a known and universally agreed upon set of conditions.

 

[Augustus Caesar]

I did both approaching this scientifically and trying t use the plain Zone System. Both worked for me, but I'm seeing you about to make the same fundamental mistake I
made and that is: trying to fit the entire subject brightness range onto the paper. That is indeed possible but rarely desirable, as it will ultimately lead to a battleship-grey print. A good-looking B&W print has some Dmax blacks and some Dmin whites to show the entire palette of greys

Correct! That is the fallacy of the zone system.

 

[Augustus Caesar]

I believe you may have misinterpreted the 1956 Kodak publication which appears to have been published in 1952. Could you provide a supporting argument that doesn't rely on that one source? Please include an explanation what the NDR is based on.

BTW, the mid-tone gradient on the reproduction curve should exceed 1.0. Generally the preferred gradient should be at 1.10-1.12, according to The Theory of the Photographic Process, 3rd edition, Chapter 22, The Theory of Tone Reproduction by C.N. Nelson (co-author of the above paper with Jones).

How so? 1:1 is what the Kodak book Negative Making for Professional Photographers says. I would be willing to listen to arguments for a little more, but what most zone system practitioners do is compress. Their prints are all too revealing of their approach. The prints are listless and lifeless.

 

[MattKing]

How so? 1:1 is what the Kodak book Negative Making for Professional Photographers says.

That reflects 65+ year old standards and materials and expectations.

 

[Stephen Benskin]

How so? 1:1 is what the Kodak book Negative Making for Professional Photographers says. I would be willing to listen to arguments for a little more, but what most zone system practitioners do is compress. Their prints are all too revealing of their approach. The prints are listless and lifeless.

Negative Making for Professional Photographers appears to be more of a publication than a book. These Kodak publications are factual but tend to generalize the information as their aim is for the non-technical photographic population, which can lead to misinterpretations. I found it online if anyone wishes to check it out https://babel.hathitrust.org/cgi/pt?id=osu.32435005178942&seq=17

Personally, I use Tone Reproduction Theory and not the Zone System. The Zone System is a simplified version of tone reproduction. In simplifying it into a system as well as Adams not being as technical as his reputation, there are mistakes or misconceptions that can cause confusion and lead to wrong conclusions. This thread is about one of those misconceptions.

You are the one making assertions; therefore, you have the burden of proof. I'm genuinely curious how, "The contrast of paper should have nothing to do with the negative density range. All negatives should be developed the same and printed on the same grade of paper." This appears to me to be about the concept of determining an aim "normal" negative and that concept isn't limited to the Zone System. It's fundamental to the photographic process. I'm just asking you to describe your thought process and show how you came to that conclusion.

Stephen

 

[Augustus Caesar]

Negative Making for Professional Photographers appears to be more of a publication than a book. These Kodak publications are factual but tend to generalize the information as their aim is for the non-technical photographic population, which can lead to misinterpretations. I found it online if anyone wishes to check it out https://babel.hathitrust.org/cgi/pt?id=osu.32435005178942&seq=17

Personally, I use Tone Reproduction Theory and not the Zone System. The Zone System is a simplified version of tone reproduction. In simplifying it into a system as well as Adams not being as technical as his reputation, there are mistakes or misconceptions that can cause confusion and lead to wrong conclusions. This thread is about one of those misconceptions.

You are the one making assertions; therefore, you have the burden of proof. I'm genuinely curious how, "The contrast of paper should have nothing to do with the negative density range. All negatives should be developed the same and printed on the same grade of paper." This appears to me to be about the concept of determining an aim "normal" negative and it isn't just limited to the Zone System. It's fundamental to photography. I'm just asking you to describe your thought process and show how you came to that conclusion.

Stephen

I would assume the vast majority of novices who come to this forum are using 35mm equipment, and are doing mostly what is called "spontaneous", "candid", or "reportage" photography. They simply want to be able to take, develop, and print well enough to get "good" results. The zone system is never going to work for them. Trying to convert them to this is really doing them a disservice.

It is relatively easy to establish what a "normal" negative is. You start with the paper grade and work backwards. Since graded papers are becoming scarce, it can require a bit more work. Also, one must first get a good enlarger, and then decide whether to use condenser or diffusion. A good enlarging lens must also be selected. Then, one takes a series of exposures with a tripod-mounted camera on a nice sunny day of a "typical" scene. I used a scene with the house across the street from mine. It has trees that cast shade. I would shoot several rolls going from 1/30 sec to 1/1000 sec at f/5.6. I would cut these rolls in half and process them separately. Based on prints from the first roll, I would adjust the development of succeeding rolls for longer or shorter times. I did this for several types of film. It is time-consuming but it provides real-world results. It also provides speed information. Most films gave best results at 1/2 to 2/3 ISO. I use Leitz enlarging lenses (50mm f/4.5 Focotar-2 and 60mm f/4.5 Focotar). I have found that 50mm lenses vignette a little.

To establish the paper grade, I suggest using Ilford's Multigrade filter no 2 1/2 on the new MG paper with a tungsten light source. Keep that fixed, and vary the film development (of a sunny-day scene) to print well on that. Once that's done, you're all set. Of course, it helps to know what a good print looks like. It should have good shadow detail and highlight detail.

If the mid-tones are "right", the photo is a success. You cannot get a 23-stop scene to print on paper with a 7-stop range and preserve normal mid-tone gradient.

 

[Stephen Benskin]

I would assume the vast majority of novices who come to this forum are using 35mm equipment, and are doing mostly what is called "spontaneous", "candid", or "reportage" photography. They simply want to be able to take, develop, and print well enough to get "good" results. The zone system is never going to work for them. Trying to convert them to this is really doing them a disservice.

Thanks for replying. I agree that there are different types of genres / disciplines that are not conducive with the Zone System. In fact, the Zone System isn't a necessary component to any aspect of photography. It's a tool and can be useful or problematic depending on how it's handled. I do feel that you are possibly making a couple strawman assumptions. The types of images uploaded to this forum demonstrates the wide range of interests of the members. I also don't believe anyone is attempting to convert anyone to anything. People share information. "Convert" implies an agenda. The purpose of this particular thread is to explain a flaw in the interpretation of the Zone System method of determining the desired negative density range.

It is relatively easy to establish what a "normal" negative is. You start with the paper grade and work backwards.

Again, I agree. So, why does it appear you are stating the exact opposite in an earlier post? "The contrast of paper should have nothing to do with the negative density range." The idea is to match the subject Luminance range to the printing material using the negative. This is basically what you say in the rest of the paragraph so you clearly understand it. Maybe I am missing some distinction between the two statements.

A careful read through of Negative Making for Professional Photographers, will show the concept of not adjusting the negative for each subject is not as much of a rule as a guideline and one that includes a number of caveats at that. I'm thinking about doing a more in-depth analysis, but for now keep in mind the idea of intent as I described in post #102. Notice that even in the Kodak publication there are two sections under the heading of Negative Quality: The Portrait Negative and The Commercial Negative. Each section states what constitutes a quality negative based on the intended use.

 

[Augustus Caesar]

Thanks for replying. I agree that there are different types of genres / disciplines that are not conducive with the Zone System. In fact, the Zone System isn't a necessary component to any aspect of photography. It's a tool and can be useful or problematic depending on how it's handled. I do feel that you are possibly making a couple strawman assumptions. The types of images uploaded to this forum demonstrates the wide range of interests of the members. I also don't believe anyone is attempting to convert anyone to anything. People share information. "Convert" implies an agenda. The purpose of this particular thread is to explain a flaw in the interpretation of the Zone System method of determining the desired negative density range.


Again, I agree. So, why does it appear you are stating the exact opposite in an earlier post? "The contrast of paper should have nothing to do with the negative density range." The idea is to match the subject Luminance range to the printing material using the negative. This is basically what you say in the rest of the paragraph so you clearly understand it. Maybe I am missing some distinction between the two statements.

You are confusing negative density range with gradient. This is the fallacy of the zone system. The contrast (gradient) of the paper has nothing to do with the negative density range, which can vary quite a lot on a single roll of film, whereas the negatives' gradient remains unchanged in that roll. The paper contrast should be changed in cases of accidental over-development or underdevelopment (which affects the negatives' gradient), but not the density range of the negative. Assume you want to photograph a brick wall in even light. There will be a very narrow density range, right?

The gradient of the paper should be fixed (within narrow limits). Different lenses can have slightly different contrast, and making photographs through a lot of dirty air or mist can lower the contrast enough to be noticeable, and this can call for increased paper contrast.

 

[koraks]

Assume you want to photograph a brick wall in even light. There will be a very narrow density range, right?

The gradient of the paper should be fixed (within narrow limits).

Depends on how you want the brick wall to render. So no, the paper grade "should" not be fixed.

 

[Keith Tapscott.]

Depends on how you want the brick wall to render. So no, the paper grade "should" not be fixed.

True, but wouldn't that be for aesthetic pictorial effect rather than technical reasons?

 

[koraks]

True, but wouldn't that be for aesthetic pictorial effect rather than technical reasons?

But what 'technical reasons' ultimately make the photograph?

 

[Stephen Benskin]

It's not good practice to use extreme examples to make a point. Anyone shooting this type of subject probably has an idea of how they want it to print. I doubt someone will look at the wall negative and think "I'll have to fit the NDR to the print LER because them's the rules." There's a metering adage, "You have to be smarter than the meter."

 

[bernard_L]

but what most zone system practitioners do is compress. Their prints are all too revealing of their approach. The prints are listless and lifeless.

Agreed. I had that (politically incorrect) thought looking at some (reproductions of-) prints in AA's "The Print" and "Natural Light Photography". Not a fan of Moriyama either...