This example, I hope, helps demonstrate a point of photographic theory. The attachment contains two examples of different Zone placements. Graph A produces a negative density range of 1.25 and Graph B produces a negative density range of 1.05. Both examples use the same film curve.
Question: Which example has the correct representation? Why?
Is there a correct one? That has always been one of my criticisms of various Zone systems. Are the zones on the negative? Are they on the paper? Are they in the scene?
Originally Posted by Stephen Benskin
I'm curious to see your answer. I actually try to keep the word "Zone" out of my posts and avoid posting in threads with "Zone" in the title, because I don't think there is a definition of the term that everyone agrees with. The reason I read this one is I saw your name on it and am interested to see the response :)
It's all relative to what expectations and parameters you set for your own workflow based upon a specific film and development regimen, and how it looks in your preferred print medium. There are no
hard rules. The Zone System is nothing more than a kind of shorthand for labeling normal dev time verus
expansion, versus contraction etc. Practitioners often place Zone II at the threshold of desired shadow detail in the original scene, and Zone VII at the upper limit of highlight containing texture; but that's based on average conditons. Films differ; and besides, how much of the toe and shoulder of the film
you recover can be altered by things like split grade printing on VC papers all kinds of other tricks. I
personally tend to visualize the film curve itself and meter placement of the values on that; but that
takes some experience. The Zone System eases you into the concept. But its all based on personal
testing to determine what you expect from it.
Okay, I'll take a SWAG;
If film curve remains constant it is because development remains the same.
So the placement change is caused by a camera exposure variation.
B would be correct because zone V actually lands at .6 +/- which is considered "normal" contrast.
A might be considered overexposed.
A will represent a larger chunk of the scene on film, specifically seeing farthur into the shadows.
The one on the left marks off one stop per zone, while the one on the right marks off less change in effective film plane exposure per zone in the shadows. I'd have to guess the one on the right is compensated for flare.
Now. Strike out IV and write II in its place on both graphs. Relabel all the zones accordingly. This would give the result of "placing your shadows on Zone IV".
Does that make things "better"?
No – and that is both the usefulness and beauty of the (God forbid I say it) "System". You decide where tone placements will be according to your personal visualization and ultimate interpretation of the print.
Originally Posted by ic-racer
I have to admire the electronics engineers who decided the "Zones" for resistors and capacitors.
They spaced the different values according to a set of nominal values that, given the manufacturing tolerances, statistically assures you that when you pick up the next higher part in the series, you will get a part that makes a difference.
We should have designed the Zone System that way.
I don't want to give everything away just yet. I didn't say "correct one" but a "correct representation." The question concerns the interpretation of data, and specifically in this case, contrast. Creating a test wedge and plotting a film curve is just the beginning. The key is in the interpretation of the data, and a large part of that is having a good grasp of certain principles and asking the right questions.
To be more specific about the aims, the paper is a grade 2 printed on a diffusion enlarger. According to The Negative, Zone VIII density should be at 1.35 for a negative density range of 1.25. ANSI defines a grade 2 paper as having an LER of between 0.95 and 1.15 for an average of 1.05.
Mark is right in that the two curves are the same. In fact, they are drawn from the same set of data, eliminating any question about variations in development or differences in curve shape. The scene's luminance ranges are also identical in both examples, so it isn't about how different situations can be interpreted through the knowing placement of Zones.
There isn't any direct relationship between Zones and specific negative densities except for Zone I and Zone VIII and that can really only be claimed for in camera testing. Technically with exposure, you can only place one value accurately (and that point has to be tested to be known). All other points fall accordingly depending on a number of factors. It's sometimes called place and fall and the concept is used by the Zone System. This is the concept that these two examples are about. Is the way we think the system works actually reflect how it works? Are people getting what they think they are getting from testing? How good can any testing be if the data is misinterpreted?
Bill is zeroing in on the cause, but he needs to take it further and discuss the implications, and Dale is asking the right questions.
We are looking at two different things in each of the examples. There's the film curve created by exposure to a contacted step tablet, and there are points of exposure from a "scene" superimposed on top of it. This is an important distinction. What does the x-axis represent?
I find the comparison between the two graphs relatively meaningless without further specification.
One represents a relatively "thin" negative, the other a relatively "thick" or dense one. Which one
works bests depends how you are printing. We don't even know whether you are talking about a
standard neg or a stained one, of whether you are aiming for a high-key print or a contrasty one.
I always preferred aiming for Grade 3 paper; but that's even gone out the window now that VC papers have gotten so good. Besides, different brands of papers differ in contrast and can be affected
by dev variables and toning. Like I said, it's all relative, unless you choose to make a religion out of
the Zone System like Minor White did.