Is this an inconsistency within the Zone System?

[al_divenuti]

Well, I imagine what I am about to ask has been discussed before.

But since I'm at a loss to track down any discussion within the

photo.net forums that's a complete match - I'm going to risk the ire

of the long-timers and ask away. This is going to be a long one so

hunker down with a cup of coffee if your still interested. Or, if

you have a weak bladder, don't - cuz this one will take some time.

 

Anyhow, having gotten into black and white photography in a big way

over the last year, I've been attempting to come to grips with the

Zone System. My primary tool for doing so has been Ansel

Adam's "The Negative" (after all, why lose something in

interpretation by a middle man...).

 

I've been able (I think!) to grasp the basic premise of the Zone

System; that it provides the necessary craftsmanship required to

link the photographer's visualization of the finished print to the

various controls necessary to achieve it. And this is basically

accomplished through understanding how subject luminances are

captured in the desired fashion on the negative through control of

exposure, development of the negative and ultimately printing.

The "trump card" - if you will - of this technique is its

consideration for the specific exposure scales and characteristics

of the materials (i.e. film and papers) used throughout. And it's

this material-specificity that's causing me all sort of brow

furrowing...

 

Very early in that book's discussion of the Zone System, Adams

introduces the concepts of Values and Zones. Zones refer to

specific exposures that are ultimately used to render specific

luminance Values as specific tonal Values in the finished print. So

a Zone V exposure is used to translate a luminance of Value V (as

indicated by a reflected light meter) to Value V in a print.

 

My mental train starts to really run off the tracks when Adams cites

Value V as the reference point for all Values. Value V, of course,

translates to middle gray. And that's an absolute pronouncement

because middle gray possesses a very specific (18%) reflectivity.

Adams then states that the Zone V exposure is the exposure necessary

to achieve a negative with a density that translates to that Value

in the final print (under fixed printing conditions, of course). By

decreasing the exposure by successive stops, a photographer obtains

Zone IV, III, II, etc. exposures. Increasing the exposure gives

Zone VI, VII, etc. exposures. Of course, the film speed determines

just what exposure is required to achieve that Zone V exposure.

 

This would all be well and good, but once Adams turns his attention

towards sensitometry and characteristic curves, he seems to

introduce an inconsistency. He cites that the Zone I exposure is

equal to a negative density of 0.1 + (Base + Fog density) and that

the density associated with each successive Zone may be obtained by

reading the density value indicated on the vertical axis of

characteristic curve with each successive increase of 0.3 lux-

seconds (i.e. exposure) on the x-axis.

 

Bang!

Splat!

 

That was my head exploding scattering its cranial contents in all

directions. For how can this be? It seems the Zone System has two

points of reference for determining Zones that cannot be

reconciled. If I start from Zone V exposure (and it's fixed

reflectance value) how can I possibly guarantee that a reduction of

four stops exposure will lead me to a density value of 0.1 + base &

fog for all materials? (i.e. long-toed films, short-toed films,

films with different gammas, etc.) Similarly, if I start at Zone I

with a fixed density, how is it possible to be assured that an

increase in exposure of four stops will allow me to arrive at Zone

V - which translates into a print value with known reflectance?

 

Well the Zone System has endured for 60+ years, so I'm willing to

bet there's a gap in my understanding somewhere. Anyone willing to

take a short of providing some illuminance?

 

Thanks in advance!

[d_poinsett]

By altering development time, you alter the slope of the curve that relates density to illumination. (Developer, temperature, agitation, and film type play a big role in the resulting curve but these are usually assumed to be held constant for any given film.) By altering the slope of the curve, you fit the illumination reference points mentioned in your post to the densities sought. Voila! This is what doing your own tests will reveal: how time adjustment alters the slope using your film and process. Knowing this, you can fit a range of illumination into a range of negative density. Negative density range has a direct effect on the range of tones in the resulting print.

 

As much as anything, this is what gave Adams the ability to previsualize. By knowing the sensitometry, he had latitude in placing tonal value in the finished print. In saying that, I'm not making a case for previsualization but rather showing that understanding the principles which control the materials gives you choices.

 

If you are interested in the the technical elements of sensitometry, you may be a good candidate for Phil Davis's book, "Beyond the Zone System". It's a good companion to Adams's "The Negative".

[henry_a]

Read the introduction to "The Negative" again, your answer is there. Such as this statement "...but we thought that such an approach could be imaginatively adapted in general work and would offer a considerable degree of negative exposure and development control for interpretive and expressive objectives."

 

It may be for Adams' example film cited in "The Negative" that the numbers used are correct. (it might also be that there is no such film!) The idea is that you will test your materials and come up with your own numbers that work for you - your film, your chemistry, your meter, your lens, your paper.

 

The Zone System is a guide to help you make consistent negatives so that you have a chance to make a photograph like the one you had in mind when you pushed the button. And thats all it is - its not exact rocket science. And you have the option of using some or all of the system as detailed in "The Negative" or other writer's interpretations that go to greater or lesser lengths. Its an outline describing a natural phenomenon of light, silver and chemistry. And it is flexible so that you can adapt it to your work.

[conrad_hoffman]

The key is in your last paragraph. There is no guarantee that Zone V is going to end up as an 18% reflectivity patch in your print. You set your EI based on the .1+bf point, based on meter readings 4 stops above, then get the development right for Zone VIII. Everything else has to follow the curve; it has no other choice. When you print, if you got the development right, the high and low values should fall at the correct shades of grey. Again, everything else has to follow the curve, and that's not under your control. Fortunately, the midtones are (and really need to be) linear and on a slope of 1, thus Zone V is a mid grey, but there's no hard connection to 18% or any other value.

[lachaine]

I applaud you wanting to understand the zone system from "The Negative", but it seems like you're way overcomplicating it for yourself. I've read it too, but there's a lot of stuff in there you don't need to know to apply it. This is one time when a "middle man" might be useful. It's actually very simple. One book I might suggest is Brain Lav's "Zone System: Step-by-Step Guide for Photographers.

[bruce watson]

I love Adams' work. I love his dedication to education. I don't love his writing style. And mine's not any better, sigh....

 

The ".1 above FB+fog" idea and the "zone V is the center" idea are about two different things. They are connected, but only loosely.

 

In order for any system to work, you have to define it. What Adams is doing with the ".1 above FB+fog" idea is defining the start point for his zonal scale. This is the point where you first begin to get meaninful data on the film. It is also the point from which the toe of the characteristic curve originates. All he is doing here is telling you how to find this point, which in turn defines your EI. Without the EI, you don't know what to do with the meter reading for zone V. What shutter speed and aperature do you set? Depends on your EI.

 

After you determine your EI, you have to determine your normal development time for your film development system. For this, you look for a Zone VIII density of somewhere around 1.2 or 1.3 (depending on your enlarger light source). Doing this creates your negative's normal gamma (Kodak calls this "contrast index). What N+1 development does is to increase the negative's gamma. Similarly, N-1 decreases your negative's gamma.

 

Only after you have your EI nailed and your normal development time set, can you use your meter reading (zone V) to help you determine your exposure, in the context of your EI and normal development time.

 

So, they are separate ideas that are loosly connected, yes? My explanation is probably as clear as mud, but at least I tried ;-)

[donald_miller1]

Someone mentioned the BTZS by Phil Davis. In my opinion that system makes much more sense then Adams' book(s). I say this as a photographer that did all of the testing etc. that Adams Zone System relies on for it's successful institution and I used it for well over 15 years.

 

The one thing that Adams' failed to address in a meaningful way was a test of the paper to see what negative density range would be required to fit the paper. Instead he assigned arbitrary Zone VIII density values that may or may not be suitable with a given paper. While I think that the Zone System is better then no system, it does miss the target by miles in some instances.

[rick_jones5]

"How can I guarantee that a reduction of four stops will lead me to a density of 0.1 + base and fog for all materials?" You can't! You must test each film and developer combination separately by adjusting your personal speed rating (E.I.). Only then can you be assured a -4 stop exposure will result in a specific density. "How is it possible to be assured that an increase in exposure of 4 stops will result in a Z5 density?". After determining YOUR speed rating necessary to attain a specific Z1 density (nothing holy about .1 over B+F) you begin adjusting your developing time +/- until you attain the desired densities for areas exposed up thru Z8. This approach works due to differential development, that is, development effects the low zones very little and the higher zones a bunch.

[doremus_scudder1]

Al,

 

I know you've had a lot to read, but you seem like the patient type, so here's my take on the situation:

 

First, Adams' choice of Zone V for "matching" print and negative values is based on the fact that most meters are calibrated to render a middle gray, so choosing this value as a starting point makes sense. All exposure determinations for all other Zones have to be calculated from a basic Zone V meter reading unless you have a meter that has been modified to make it easier to read zones on. This is why Adams chooses Zone V as a standard point and for no other reason. The actual system calibrations normally do not concern Zone V at all. Also, most people can relate to middle gray better than "Zone III" or "Zone VII" when first learning the system. However, as one becomes be conversant with the visualization aspect of the system, one realizes that every zone has its own "feel". By using the meter and the knowledge of what the system will do, one can get a pretty good idea of what the final print will look like. More often than not, the system tells us what it is going to do, and not the other way around.

 

So, at the risk of oversimplification, here is the "Zone System Skeleton", i.e. the basic information you need to understand and use it. Keep in mind there are always three interacting elements: The original scene, the negative and the final print. Negative values can theoretically be printed to any final print value. We assign these values to make the best use of the information on the negative. Also, keep in mind that the meter you are using wants to render whatever you point it at as middle gray (the real reason for Adams love for Zone V!), and you must adjust exposure to get the other zones. An advantage of the Zone System is that we can do this easily by one-stop increments instead of worrying about the log2 values used in sensitometry.

 

1: All films have a minimum exposure below which no information is recorded on the film. You need to find this point and call it "Black" in the final print. You also call it "Zone I". As you can see, this is directly related to film speed. Finding Zone I, therefore, is all about film speed testing. Adams uses the 0.1 above fb+fog value, I prefer to do proper proofing tests on the paper I use and thereby eliminate the densitometer. At any rate, this step must be done first and gives you your effective film speed, or E.I. (exposure index).

 

2: The more you develop film, the more density you get for a given exposure. Fortunately for us, this happens proportionately to the exposure, with the high-density values being affected much more that the low. This means that development can be used to control the contrast on the negative. Why do we want to do this?

 

3: Photographic paper has a limited contrast range (even with all those filters and grades). The negative can hold a lot more than we can get out of the paper, (but, who wants to look at negatives hanging on the wall). So, in short, we use our meter to evaluate the contrast of the scene and manipulate the development of the negative so that this will fit (more or less) precisely the contrast range of our printing paper.

 

How do we apply this knowledge?

 

We work to create a negative that is suitable for the paper, which is the limiting factor. We know (from step 1 above) that we need a certain amount of exposure for the film to work at all. We also know that the low values of the negative are the least affected by development changes. It stands to reason, therefore, that our exposure should be based on a shadow area. That is why most Zone System photographers use Zone III (or VI) as a basis for their exposure. Before we start anything, however, we must determine film speed. This is somewhat independent of the Zone System, but indispensable. Having done this (either with the densitometer or by Proper Proofing), we must decide how much to develop our negative. This, of course, requires knowing the contrast range in the scene being photographed. But every scene is different and....

 

Yes! And here come the arbitrary part of the system. We simply establish what we want to be "Normal". Adams defined it as a scene that contains Zones III and VII which are rendered as detailed shadow and detailed highlight (we could use other definitions, but these work well for starters). You will notice that Zone V is conspicuously absent here. Where is it then? On your meter! You usually need to play around with your meter, which is set to render approximately Zone V, and make some mental calculations in order to determine an exposure for Zone III or any other zone than Zone V. So, go out and find a normal scene, defined as one which has a Zone III area you want rendered as a detailed shadow and a Zone VII area you want rendered as a detailed highlight. You decide, you imagine, you visualize. (Here are both the weaknesses and the strengths of the Zone System. Beginners are usually horrible at visualization. However as one acquires skill, one becomes able to mentally picture to a high degree of accuracy how the final print will look.)

 

But, back to business: Remember now, that our exposure should be based on a low value like Zone III, so, point your meter at that Zone III area and figure out what the proper exposure is based on your effective film speed. Now, what will that Zone VII area look like in the final print? We don't know that yet, since we haven't arrived at a standard developing time for "Normal" yet. This is what we must do now. So take a few exposures of this "Normal" scene and develop them for different times. If you have no idea where to start, use the manufacturer's recommended time and shorter times (most manufacturer's times are too long for Zone System work).

 

Now you have a few negatives, developed to different contrasts, of a "Normal" scene. Simply print them all so that the Zone III value looks as you imagined it (again, you decide). Now examine the Zone VII values to find the one that looks how you imagined it. Once you have found it, note the developing time. You have just found "N".

 

Before we go on to the N+ and N- parts of the Zone System, let's stop a minute and see what we have and how it actually works in the field. Here we are photographing a normal scene. How do we expose? Easy, we find a low value, decide where we want it (i.e. what we want it to look and feel like in the final print), meter it and calculate the exposure necessary to do that. We can only determine exposure for one such Zone in a scene. What about all those other values and zones in the scene. They just end up where they may, as determined by our chosen exposure. However, we can read them with the meter, find out what Zone they will be rendered at if we develop for the "N" time and get an idea of what they will look like in the final print. If Zone VII in the scene ends up being something you want rendered as a detailed highlight, then wonderful! Just develop for the "N" time and we'll be in the ballpark. If the Zone V in the scene at the same time, however, looks like it will be rendered darker than we want it, then, tough luck. We cannot move one Zone without moving another. This is the system telling us what it is going to do. There are no controls available to tweak things around inside the basic contrast scheme. Maybe we can dodge a little, or print contrastier and burn the highlights or decide not to take the photograph at all. At least we now have a clearer idea of what will happen and can plan ahead.

 

But, what if that area you want to be rendered as a detailed highlight (Zone VII in the print) turns out to have a metered value of Zone VI? Well, we can develop longer to expand the contrast. If it falls on Zone VIII, we can develop less. How much? Well, go out and find some scenes like these, take several negatives of each, develop for different times (more for the N+ ones, less for the N- ones), print them so the Zone III is how you imagined, evaluate... You get the idea.

 

Now where is that Zone V? It is still there on your meter, but by now you have become completely adept at mentally calculating the right exposure for all the different Zones, or have taped some kind of Zone Dial or Zone Ruler on your meter calculating wheel in order to facilitate this. Zone V is a reference point for all other values, but ONLY on your meter. You will notice that exposure and development are based on other zones. So, forget about Zone V being some kind of calibration point except as concerns metering the scene.

 

Hope this helps a bit, and good luck.

 

[pascal_miele]

The holy book (the print) is true�It�s the holy book!

 

The ZS need to be adapted�.. when it�s false�.it�s true !.

 

After a long reading of Adams and others, ZS is FULL of inconsistency.

 

Look to the original sensitometry and lets Adams RIP.

[tim_curry]

Al,

 

Save the money on beer, Tylenol and therapy. Get a copy of Fred Picker's "Zone VI Workshop" and relax. He takes what Adams says and makes it easy to follow so you can do tests and then understand what you are doing.

 

Basically, the "straight line" segment of a film curve is not necessarily a straight line. Sure there is a toe & shoulder to think about, but each film and developer combination is different. If that straight line has a soft curve in the center, zone V can be above or below what your true zone V value is, but why worry? This is why film testing, although a P.I.T.A. is so important to getting good exposures. Once you have a combination which works (camera, meter, film, developer, paper), forget testing and just shoot. It will start to make sense once you have done some tests and begin to actually apply the theory to the practical.

You will learn plenty from your mistakes and triumphs. That's the fun. Please contact me off list if you have any specific questions. I just went through this over the last year and it does get better. There are many good people here with lots of information. Use it all with a large pinch of salt. tim

[tim_hardin]

Al,

 

Take a look at this site http://www.onlinephotography.com/bw.html

 

If you downlaod "The Relatively Non-Technical Zone System For Black And White Photographt" by Terry Staler. It will help you in understanding the Zone System a little better, and help get you head back on right...

 

Good Luck,

 

Tim

[sjmurray]

Al, you have asked a very good question and have gotten many very wise and helpful responses. My advice from my own experience of 30 years of black and white photography is to keep it simple. I have read the Zone System from cover to cover many times. I use a spotmeter with the zones marked on the dial. Even when I shoot color I look at the scene as zones to get a feel for the values and extremes. I judge exposure based on what values I am visualizing for the final print, which may be different from the actual scene. This takes practice. I always develop a "normal" neg, that is, not too flat and not too contrasty. It doesn't take a densitometer to see this when you go to print. I have never done formal testing either. I use familiar film/developer combinations so I know what to expect when I develop.

 

Printing is an art all unto itself. Even after applying the ZS to a neg, AA himself did a lot of dodging and burning as he printed. If you look at his prints you will see that his interpretation of the original scene is often profoundly altered to create an emotionally more powerful image. An image on paper is never going to look like a real scene and that's not the point. Its always an interpretation. The good prints have a strong impact on the viewer through composition and the way the textures and tones are interpreted.

 

What I'm saying is that even if you get your exposure and development down pat, you still will find yourself posed with the challenge of getting that print to express what you visualize in your head. That takes a lot of practice. I can be a lot of fun if you don't overwhelm yourself with trying to get the perfect negative, because that just doesn't guarantee the "perfect" print. Shoot for a "good negative" and work with it. That's my two cents. Have fun.

 

Steve