Each quadrant of the tone reproduction diagram illustrates one part of the photographic process. The true strength of the diagram comes from showing who they interact. As Jones writes about the negative, “it makes little difference what its characteristics are, provided a print of satisfactory quality can be made therefrom.” For example, if the goal is to have maximum separation of the shadows, the gains from picking a film that emphasizes the shadow contrast can be lost with the wrong choice of paper. This can only be known by evaluating the process as a whole.
Perhaps the most important quadrant is the tone reproduction curve. It is the summation of all the steps in the process. With proper interpretation, the curve can be used to evaluate how a change in one part of the process effects the whole. For instance, it will show how the expansion of the shadow contrast will cause a contraction in highlight contrast. Yet even the tone reproduction diagram doesn’t tell the whole story. As it is only concerned with the objective reproduction of tones. It doesn’t explain how the tones in the photograph will appear to the viewer.
One test evaluated how tones are perceive through the effects of adaptation and simultaneous contrast under different levels of illumination. The test used a gray scale containing five steps of known luminances. It found that “decreasing the illuminance by a factor of ten caused the brightness of the white step to decrease by a factor of less than two times. A dark gray step, however, remained the same in brightness. It showed perfect brightness constancy. The darkest step on the scale actually increased slightly in brightness when the illuminance decreased. The remarkable finding is that a ‘black’ object of low reflectance becomes brighter when the illuminance is decreased and darker when the illuminance is increased, whereas a ‘white object’ shows the opposite trend.” So how the tonal relationship of a photograph can change depending on how it's illuminated. The way I interpret this is shadow contrast appears greater under higher levels of illumination.
The following graph shows the effects of light and dark surround on the perception of brightness in a photograph. Not only would this apply to what surrounds the entire photograph, like a matte or wall, but how the tones respond to other tones within the photograph itself as the second set of examples illustrates.
This last example illustrates local inhibition and adaptation of the eye on a gray scale. The x-axis is luminance and the y-axis is brightness. The first graph is of the gray scale surrounded by a medium gray background. The second example is of the gray scale surrounded with a white background. The white surround makes the gray scale appear darker, increases the apparent contrast of the three lightest steps and decreases the contrast of the two darkest steps. The third has the gray scale with a white background as well as white separating each step which shows an even greater effect than the second example.
The distribution of the tones in the photograph appears to play a part in the perception of tonal relationships that is separate from the one the negative and print contrast plays. Something to keep in mind the next time someone attempts to judge photographic quality based only on the negative curve.
It all seems like it should be obvious, yet too often people tend to compartmentalize the calibration of their materials and processes. You get your hands on a densitometer and the next thing you know you're developing roll after roll trying to home in on a 0.1 for EI and 1.2 for Zone VIII and the right curve shape, without making actual test photographs and prints along the way. After all that work you find out you're not making the negatives you need.
Some people need the technical aspect in order to continue with actual photographing. I see nothing wrong with it. But, there is a point where you do get too far into the technicals and what counts (the actual photograph) begins to suffer, not only from lack of time but the brain begins to think in some skewed directions. I'm at the point that it should suffice to test materials with equipment for normal exposure and +/- (1 and 2) developments without trying to break it down too far. So, once I'm convinced my testing gave me consistency, I'm good for a long time.
At the end of the day it is the actual photograph and how it is received, especially by the photographer himself, who should be the ultimate judge of his own work (unless of course, it is commercial work that puts food on the table, then such standards don't often apply).
What on earth are you talking about?
Originally Posted by Stephen Benskin
“The contemplation of things as they are, without error or confusion, without substitution or imposture, is in itself a nobler thing than a whole harvest of invention”
Tone reproduction theory. In broad terms, how the luminances and luminance relationships of the original scene are ultimately rendered in print values. The quadrant diagram Stephen refers to is a graphical way of following the original values in the scene through the various steps to the final print. There are variables, controls and limitations along the way that change these relationships. The general idea is if you really want to "predict" how the scene will look in the print (Zone System, for example), you need to look at the entire system from subject to print. In other words, it is not enough to know your film curve. There is also the paper curve, flare etc.
This particular thread goes a step further than the objective transition from subject to film to print, and adds subjective aspects like the conditions under which the print is viewed, the brightness of the background, the way our eyes react to value relationships in the print.
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Ha yes, Michael, and since much of it is indeed "subjective" that's when a lot of theory goes right out the window. After all, what is truly, technically "correct", from a negative/development/paper/curves etc, point of view, when you start adding the many subjective aspects? All I know is that if would ever start worrying about all of this, I'd probably never make another print..or I may just shoot digital and make inkjet prints and yes, I am understanding and respectful about the fact that a few people do care about all of this, but from what I can tell, I don't see it translating to better photographs/prints, especially these days.
Originally Posted by Michael R 1974
And Jones would not really disagree with you, Max. As long as you can make the print you want out of the negative, not much else matters. This must be the case, since great prints can be made, and have been made from poorly controlled negatives - which is testament to the flexibility of the process and our materials. The theory here is not to tell you what a correct negative is. It is to help one understand how what we see in front of us translates to the negative and then to the print. There is a series of steps in the end to end process, yet many practitioners of applied densitometry methods keep these steps (exposure, negative, print) in silos.
Assuming you have no interest in applied sensitometry, ok. But - exposure and tone reproduction theory probably should be of at least some interest to all the people out there who do use the ZS, BTZS and whatever else, because while these systems give people the sense they are in control of the results, they may not actually be getting the negatives they think they are. Again, the flexibility of the process often allows us to unconsciously work around these issues (especially if we refine our printing skills) but why not try to understand a little more about what's going on? Why do we find a personal EI that differs from box speed? Do our expected shadow exposures end up where we think they do? How does our perfect negative translate to the paper? Or at the very least, if someone has no interest in how these things actually work, don't write a book or with all kinds of misinformation.
Note Stephen had his own reasons for the thread so I'm not putting words in his mouth. These are just my views.
Last edited by Michael R 1974; 04-07-2013 at 06:14 PM. Click to view previous post history.
I agree with you, 100% Michael. No problem with that all. In fact, I have used BTZS, have tested film and paper, and have worked extensively with densitometers, especially for photogravure. I think knowledge is a wonderful thing, and yes, it can certainly lead to a better understanding of "how" things work. I just don't think it that, in general, all of this knowledge gets applied to produce meaningfully better images/prints. Actually, in many cases, it tends to bog down the photographer to a point where he/she becomes too enthralled in the details and forgets about the larger picture (pun intended)
Originally Posted by Michael R 1974
From personal experience, when I have used BTZS and ZS, with paper testing, I was able to produce "ideal" prints. With all tones in the right place, without much dodging or burning needed, etc etc. Correct prints, yes. Moving? For me, not. It wasn't until I realized that to print what I had in mind, to achieve my vision, I had to throw away some rules and think outside the box a bit more. The latest batch of prints I have posted are the results. Of course, not everyone will like that, but I do. It's how I see things. If I was going to play by the rules, those images/prints, would not look that way. I am over-exposing, I am overdeveloping, and printing on grade 5. All of it without the use of a densitometer of course. Interestingly enough, most of those prints, have required no dodging or burning at all, except for maybe a few cosmetic reasons, and not to fit the negative on paper.
Anyway...these are just my opinions, of course, and I think Stephen does wonderful work by sharing his incredibly extensive knowledge.
I wrote this whole response but managed to lose it. So in a nutshell. The purpose of this thread was to present influences other than the film and paper that effect the way a print looks. Ultimately it's all about perception, so this should be a topic of interest for all photographers. The take-a-way are some practical common sense concepts. Concepts many people already know either through experience or instinctively.
The film is only one component in the photographic process. Also there's more than just the physical process to consider.
From the concept of surround - Whether the print is hung on a white wall or one with a darker tone influences how the print looks. Adams talks about this. The print will pop more on a gray wall than white one. So, whenever possible considering how the print will be displayed should factor into the printing, which includes the matte. I always view test prints in a matte. We must also understand that the tones in the print can look different depending on the tones around them. It's not simply a matter of placing something on a given Zone. How it is perceived isn't always in our control.
From the concept of local inhibition and adaptation - Also when ever possible, consider keying the print to the illuminance level of the room the print will be displayed in. Museum and gallery lighting or average household. Or consider axillary lighting. Print to a standard illuminance, then display it with that illuminance.
This is about how the tones of your art will be perceived and that there's more to the photographic process than just the negative and the print.
Last edited by Stephen Benskin; 04-07-2013 at 07:49 PM. Click to view previous post history.
I'm guessing that he just wants to discuss the issues since there didn't seem to be any questions asked.
Originally Posted by Michael R 1974
[update: Stephen seems to have already answered this whilst I was still typing]
IMO it would have been better to preface the post with a purpose, probably a lot of members aren't interested (or at least think they're not) in such things.
I think, for the most part, prints are generally seen with a (somewhat) "average surround," where these effects don't matter a great deal. But if one wants to "tailor" their prints for a specific non-average location, an understanding of the preferred tonal curves might save some time. (Assuming they already had a collection of film and paper curves, and a means to translate to tonal repro curves.)
One can get to the same place through pure trial and error, so there's more than one way to get there. When someone tries different developers and papers to find what they like best (with different scenes and display conditions), I think this is what they're doing.
Actually, being subjective doesn't mean that it's unpredictable. There are, in fact, a number of so-called "color appearance models" that take things to such an extreme that, dare I say it, even Stephen might think is excessive.
Originally Posted by MaximusM3