Paper Zones

Discussion in 'Exposure Discussion' started by Stephen Benskin, Apr 26, 2013.

  1. Stephen Benskin

    Stephen Benskin Member

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    I’ve always found it a bit strange that the Zone System is so vague when it comes to calibration. The argument that it’s because a Zone is a range doesn't cut it for me. Just because a Zone is a range doesn’t mean a range can’t be defined and the mid point of that range determined. Adams does offer a target negative density range, and based on that people have extrapolated approximate target densities for the individual Zones.

    Paper is another matter. Adams is even more vague on paper calibration. He doesn’t even touch on log exposure ranges. This makes it more difficult to extrapolate the reflection densities for the various Zones.

    What I’d like to do is to present a series of models without any judgment. There is a question, however, that I’d like to propose. People talk about placing a subject value on a particular Zone, yet does this have any real meaning if there isn’t a corresponding value on the print?

    All of the examples use the same paper curve. The only difference is how the print Zones are distributed on the curve. These are only a few possible models. There are probably other sources with different values.

    One approach to defining the paper Zones is to use equally spaced log exposures. As the paper has approximately twice the gradient as the negative. Each 0.30 subject luminance difference would translate into approximately 0.15 log exposure difference. The first example begins with Zone VIII at 0.04 over Pb+f and each subsequent Zone is at intervals of 0.15 log exposure.

    Paper Curve - Equal spaced Zones.jpg

    The second example uses the reflection densities as defined in Way Beyond Monochrome.

    Paper Curve - Way Beyond Monochrome.jpg

    The third example uses the preferred reproduction densities in Jack Holm’s paper Exposure-Speed Relations and Tone Reproduction. His values are adjusted to include Pb+f.

    Paper Curve - Preferred Zones.jpg

    The fourth example shows the placement of the Munsell Values on the paper curve. These values are psychophysically determined to appear equal spaced.

    Paper Curve - Munsell.jpg

    The fifth example is from the third quadrant in a tone reproduction diagram which has a subject luminance range of 2.10, slightly more than one stop flare, and a negative processed to a CI 0.58. This example isn't suggesting these are the only possible Zone placements under the stated conditions. A slight tweak in the printing exposure can easily lighten the mid-tone, placing Zone V at RD 0.74 without too much of a change in the the highlight and shadow values.

    Paper Curve - Zone - Quad 3.jpg
     
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  2. Bill Burk

    Bill Burk Subscriber

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    This is one of the concepts where I have a short-circuit.

    Here is how I relate Zones to Print.

    I took a step wedge that had been developed to "N" and contact printed it on Grade 2 paper. This related sensitometric exposure of the negative to print.

    I selected a white patch on the test print and treated it as IX. Then, skipping steps to make them one stop apart, I cut chips out for the different zones down to Zone 0. (I estimated 0.4 flare when selecting representative chips for II, I and 0).

    Now if I examine a scene that I could call "N" with the light meter... Once the meter is set, everywhere I point the meter corresponds to a specific print chip. If I am happy to accept that chip as what I am likely to get on a print of the scene, then I use the indicated exposure from the meter.
     
  3. Stephen Benskin

    Stephen Benskin Member

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    Bill, sounds to me like your approach to calibration is like example five.
     
  4. Bill Burk

    Bill Burk Subscriber

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    I think you're right, example five.

    But guess what I did wrong. I calibrated to a contact printed step wedge, not an enlargement as I had planned.

    So enlarger flare isn't properly represented on my Master II.
     
  5. CPorter

    CPorter Member

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    I see the range between zones defined by the following as well as their midpoints, but perhaps this is not what you mean, IDK:

    "It must be understood that these values (i.e. the gray scale values in figure 4-3) are merely points on a continuous scale that ranges from full black to pure white. Each single value represents a range of grays slightly darker and slightly lighter, and the individual gray values produced in a sequence like this one (again, figure 4-3) are each the midpoint of their respective zones." -AA, The Negative
     
  6. artonpaper

    artonpaper Subscriber

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    I think Adams was more improvisational than systematic when it came to printing. I base this on interviews I've heard with him and the comparison of his earlier prints to his later prints of the same negatives. Also, he did make the statement that printing was a performance. I realize this doesn't negate wanting to ascribe numbers to print values, but I'm not sure why one would need to.
     
  7. markbarendt

    markbarendt Subscriber

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    I'm finding that in my printing that I am happier about the prints when I can see faces that look normal in the room light where they are hung. If a face falls too dark, when I look at it from across the room, because I tried to protect the highlights, that print typically fails.

    I am finding this true regardless of the original scene, campfire just after sunset or sunny 16 doesn't seem to make that much difference, some but not a lot.
     
  8. Stephen Benskin

    Stephen Benskin Member

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    Figure 4-3 is just a group of gray patches. This is what I mean by vague. In The Print he writes, "It is my opinion that the photographer need not devote much time to the theoretical study of print sensitometry." Now, it's not necessary to understand sensitometry to make a print. That is not the point of this thread, but the characteristics of the paper as well as the subject determines the aim contrast of the negative. What does this say about a methodology that is supposed to be about controlling the materials.

    On page 55 of The Negative , there is a table which has subject luminances compared to negative Zones which are compared to print Zones.

    Zone Increments.jpg

    As Zone I is at 0.10 over Fb+f, the negative Zones can be extrapolated as being at intervals of one stop subject luminance differences. On the negative as well as the print, flare will need to be accounted for. The print Zones, would then be where the negative Zones fall on the print. Example 5 appears to be the most representative of this concept. Exact placement is still unknown as there isn't a RD defined to key any of the print Zones on. This would suggest Zones are not intended to appear to be a gray scale of equally perceived steps. From a sensitometric perspective, this is the approach that makes the most sense, but as the intention of the Zone System on this point remains vague, any of the examples are potentially valid.
     
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  9. CPorter

    CPorter Member

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    Yes, it is just a series of gray patches, no doubt about it. Elaborate on what you mean by a Zone being a range?

    But, it should not be surprising that you can go through a text like The Negative----which is meant to teach the fundamental concepts of the black and white photographic process----and find where the subject can obviously be treated in much, much, much deeper detail.
     
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  10. Stephen Benskin

    Stephen Benskin Member

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    You qouted the definition yourself, "Each single value represents a range of grays slightly darker and slightly lighter..."

    And I am attempting to explore the deeper detail that wasn't in the book. Actually, I'm attempting to illustrate conceptual implications and not define a specific set of reflection densities.
     
  11. Doremus Scudder

    Doremus Scudder Member

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    Adams, I believe, constructed the Zone System with the primary purpose of simplifying sensitometry in order to create a useful tool for visualizing final print values.

    I would tend, therefore, to submit that over-quantifying the system is somehow defeating its purpose and returning it to the science of sensitometry, removing the simplification and, possibly, the visualization aspect as well.

    As you have likely gathered from my earlier posts, I do all my Zone System calibrations visually, using no numerically quantified values at all. What I do have in the end, however, is a print of all Zones from a particular development scheme on the paper I use most often (made with camera and enlarger to take flare at both ends of the process into consideration).

    This enables me to know, within a certain acceptable margin of error, what print value a given reading on my exposure meter will yield in a print on that paper (with a particular development scheme). The fact that the print values corresponding to an exposure reading/development scheme/paper choice are not quantified does not deprive them of meaning. Just the opposite for me. I find that being able to "play" my scale of greys at the time of exposure, either from a good memory of where the tones fall (similar to a musician crafting a melody), or even directly from the Zone Ruler that I have printed, relates much more directly to what I will end up with in the final print than a lot of numerical data.

    The fact that paper scales vary with brand and with batch plus the fact that papers come and go (mostly go...) and are reformulated regularly, not to mention the different amounts of camera/enlarger flare, effects of print developers, etc., etc., suggests that an approach that takes the particular paper and grade and developer into account along with the entire work-flow from exposure to print is the only practical approach. Performing strict sensitometric tests on every paper I use with all my development schemes with all of those variables taken into consideration would be a daunting task, and the resulting data likely less useful to me in the field than the Zone Rulers I make from negatives exposed in my camera and printed with my enlarger.

    It is in this spirit that, I believe, Adams wrote, "It is my opinion that the photographer need not devote much time to the theoretical study of print sensitometry."

    And, while I agree that "the characteristics of the paper as well as the subject determines the aim contrast of the negative," I am not convinced that this needs to be sensitometrically quantified. The methodology need be no more complex than necessary to deliver desired results.

    One of the things I learned very early when printing Zones is that the print Zones are nowhere near equally spaced; nor do they correspond to many of the commonly used descriptions; Zone V rarely ends up being 18% grey... That is irrelevant; if one simply accepts the unevenness of the print Zones, that there is less separation in the shadows and highlights than in the mid-tones, and that Zones fall where they fall, then suddenly one has a very powerful visualization tool in hand. One uses one's knowledge of how the system works to craft a negative that will yield desired results. Being able to do this visually is, in my opinion, the central advantage of the Zone System. The simplification and the reduced (or eliminated) need for numerical quantification coupled with the ability to develop a keen sense of what print values given exposures will yield is, for me, the "intention of the Zone System."

    For me, there is a corresponding value in the print for exposure values I give a negative. They aren't linear and certainly aren't numerically quantified, but I know rather well, i.e., within the confines of the accuracy of my calibration, what print values I'm going to get. That, for me, is real meaning.

    Nevertheless, printing remains an art; slight changes in print exposure move the mid-tones more than the highlights and shadows, as you mentioned above. Subtle changes in contrast, dodging and burning, bleaching, etc., etc. all contribute, often in ways often too small to quantify meaningfully, to a fine print that really sings. My goal with the Zone System is to be able to visualize well in the field and create a negative that I can use these printing tools on (as opposed to one that is too badly exposed to be able to work with easily). Again, I think this is the primary purpose of the Zone System; we need not be more accurate than that.

    In closing, I guess I'm trying to say that, at least for me, placing a subject value on a particular Zone does have real meaning, but a directly visual instead of a numerical one. Also, I think the intention of the Zone System is purposefully imprecise (I wouldn't really call it vague). This allows for individual tailoring of the concepts of the system in order to achieve predictable and repeatable results within a manageable margin of error using one's own purposes, materials and procedures; and this without lots of lab work.

    Best,

    Doremus
     
  12. Bill Burk

    Bill Burk Subscriber

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    Thanks Doremus,

    Many teachers and advisors stop short of doing sensitometry in the print stage. I recall reading where it can be used to provide "possible suggestions of paper grade to select" but ultimately the guide I was reading left the final stage up to the whim of the individual.

    But I don't want to short-circuit what you are suggesting, if you intend to carry forward the study that may have been dropped by other well-respected teachers... They didn't see a value in it. But even if the final decision rests with the individual, there is value in a well-rounded theory.
     
  13. CPorter

    CPorter Member

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    Ok, I thought so, but I wasn't sure if I was on the same train of thought that you were getting at.
     
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  15. Stephen Benskin

    Stephen Benskin Member

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    Doremus, I agree with much of what you've written. In fact the part that's quoted above is basically the point of this thread. The quantifiable aspect of the paper that is important is the LER. Along with the the subject luminance range this determines the processing. This is something that Adams doesn't discuss, although he has target negative density ranges for both diffusion and condenser enlargers which indicates he knows that there needs to be a way of defining the parameters of the materials. Why doesn't he just take it a step further and connect the negative density range to the paper in a more direct way?

    Individual Zones, either in the negative or print, are not possible to accurately peg in most circumstances. Flare and curve shape are two of the primary reasons. Yet there is a false sense of precision among Zone System practitioners. I believe part of the reason is because the Zone System is vague on the relationship between the negative and the print. Expression in the print making stage is very important. For me, the idea of testing is to define the working range and everything in between is fair game for printing. The world tends not to organize the relationship between scene luminances just to fit my creative needs. This is fixed in the printing. All the Zone System can do is to help determine how to fit the scene luminance range onto the paper log exposure range and that is basic sensitometry. The Zone System's innovation is providing a intuitive visual tool to help combine artistic expression with sensitometry.

    Negative Zones are about defining the luminance range and consequently the processing. Remember in my original post about placing a scene luminance on Zone III? Other than determining where the point of exposure is within the context of the luminance range, what does this really mean if there isn't a meaningful connection with the print. What I'm suggesting is not about attempting to quantify the print Zones, but exactly the opposite. The fact that there are a number of equally plausible examples is proof of that. There is no specific negative density for Zone III that has a corresponding reflection density on the print. A lot of people don't understand this and strive for, or believe in a precision that doesn't exist.

    Bill, something that I find very interesting is how the compression of the shadows is the opposite of what is desired visually. Munsell's studies found that the eye compresses darker tones, so in order for them to appear equally spaced, they needed to have more separation than the luminances alone would indicate.
     
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  16. CPorter

    CPorter Member

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    You say, "when printing zones", so I assume in the production of a gray scale. I agree with you on just about everything in your post. However, creating a grayscale is just about as easy a thing a person can do. Just to recap it, one has to print the Zone V negative to precisely match the tone of the gray card, then using the same print exposure time, proceed with printing all the other negative zones. In this way, Zone V will always match the gray card----the tone values and the commonly used descriptions will hold true when a textured gray scale is generated (like in the text)---I've done it as per the text, it works quite well. So, I'm compelled to question the assertion that zones are not evenly spaced, but I remain open to the contrary.

    I agree with you that it could be completely irrelevant as long as one sees the "concept" involved, but for me personally, I find it very relevant.
     
  17. Bill Burk

    Bill Burk Subscriber

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    On my Zone Sticker for the Master II, the Zone 0 through III are all "black" basically. But only IX is "white". The Zones VIII through IV do all the work. Everything below plunges into shadow.

    Maybe the reason compression in the shadow Zones works is that people are not looking in the shadows, their eyes gravitate to the lighter tones.
     
  18. markbarendt

    markbarendt Subscriber

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    I find your thought here interesting, both wrong and right in my head.

    Very much right IMO, in the sence that it may be tough to define where every subject falls.

    Wrong in the sence that I can pick 1 point, 1 zone from the scene and place it a a specific point on paper, and similarly I can pick a single point to peg on the negative.
     
  19. Stephen Benskin

    Stephen Benskin Member

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    It's subjective tone reproduction. As long as the mid-tone gradient is higher than 1.10, people can accept highlight and shadow compression.
     
  20. Stephen Benskin

    Stephen Benskin Member

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    1 point maybe. It's easy to key off a tone in printing. For black and white negative film, it's a little harder. The only knowable point is the tested speed point and that is influenced by flare. The density at the metered exposure point depends on the shape of the film curve.
     
  21. Doremus Scudder

    Doremus Scudder Member

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    Great discussion all; this is really making me re-evaluate and solidify my (often somewhat dusty) concepts.

    Stephen,

    I agree wholeheartedly that there is a false sense of precision among Zone System users. This was part of the point of my previous post. I think the amount of precision necessary to get the job done (that of making expressive prints), however, is much less than most practitioners of the ZS (not to mention the BTZS devotees...) believe is necessary.

    I think you allude to this throughout all your posts, using terms such as "vague," "no meaningful connection with the print," "no specific density for Zone III" and so on. I agree with you on this point as well. I think that having a specific negative density that relates to a particular print Zone is unnecessary and, often, undesirable. (and is, likely, ephemeral). An example: I shoot Kodak 320 Tri-X quite a bit. I often rate the Tri-X differently depending on the amount of shadow separation I'm after. This is because the film has a very long, sloping toe, which tends to compress shadow values and when exposing at "maximum" speed (by which I mean the minimum exposure to reach a Zone I density that is a barely discernible step above FB+Fog when proper proofed). However, Tri-X will hold detail well into Zone X and above. So, if I want maximum separation in the mid-tones and highlights, I'll expose at that "maximum" E.I. However, if I want a lot of separation in the shadows, and feel that some highlight compression is a fair price to pay for that, I'll "overexpose" by up two two stops. This gets "Zone III" up into the straight line portion of the film and gives me a lot more "room" between my shadow values. My "Zone III density," therefore, can fall anywhere in a two-stop exposure range. One could say that I'm placing important shadows in Zone V and then printing down... which is, in essence exactly the same thing except that my visualization is based on a print value that corresponds to my "imagination" or "feeling" of what a Zone III print density is: a dark but detailed shadow value. The description is admittedly vague, but the vision in my mind's eye is much less so.

    Moving the exposure around on the film curve for expressive purposes is just one reason why there is no "specific density" for a given Zone. Others include variations in paper curves; there is no "standard" grade 2 paper curve, and the tendency of some of us to tailor negatives for paper grades other than grade 2. E.g., I like to print some subjects on grade 3 (or higher) paper, and indicate N-1 (or N-1/2) development for negatives of such subjects. I'm thinking all the time of print densities and local contrast, but, again, there is no specific density in the negative that corresponds to, say, Zone VIII. They are obviously different in a negative intended to be printed on grade 2 paper in one tailored for grade 3. My point is simply that having the flexibility to use different densities to achieve a desired print density is an advantage if one knows their materials and has a clear idea of the desired results. Other considerations such as shadow separation and local contrast (among others) are determining factors in the choice.

    The fact that I can print any negative density to a Zone III print value (or whatever value) is, for me, liberating. I don't have to "expose by the book."

    CPorter,

    We are saying much the same thing here, just using different reference points. One important concern of crafting a good negative is adequate exposure. I, therefore, make sure I have a Zone I density (which I use as a starting E.I.) that gives me a "hint" of separation between the Film Base + Fog density when proper-proofed, i.e., printing an unexposed area of the negative at "maximum black" (actually, maximum black is also a rather flexible concept... I "choose" a black value for FB+F that is "black enough" for me. I will also adjust E.I. to give me a useable Zone III, even if it moves Zone I a little bit from my original placement). The "proper-proof" exposure and my chosen E.I. for a given development are my reference points for making Zone Rulers, or grey scales in your terminology. For "Normal" development, I target Zone VIII to give me some highlight detail and Zone IX as close to paper base white as I can get while not losing detail in Zone VIII. Again, all this is unquantified, subjective and personal, but not imprecise.

    With this method, Zone V most often falls somewhat else than 18% grey; and it can be lower for N and higher for N+1... Furthermore, the difference in perceived density change in the lower zones, say between Zones II and III, is much less than the perceived difference in density between, say Zones VI and VII. This is what I mean by the scale being uneven.

    The only problem I see with matching a Zone V film exposure to an 18% grey print value is the possible loss of shadow detail, i.e., effective film speed. If printing the Zone V density to 18% grey dumps Zone III to a place that has little or no detail, then it can no longer be used as a reference point for exposure. If you are exposing to Zone V (incident or averaging metering) and you know what you will get in the shadows, then fine, but the Zone System was really designed to ensure adequate shadow exposure and detail; this, I believe, should be the exposure reference point we use most, not Zone V.


    Best,


    Doremus
     
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  22. CPorter

    CPorter Member

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    Doremus,

    When I start to actually print a negative, I just print the negative using standard methods. But when I make a gray scale, the scale itself is centered around the exposure time that produces the Zone V negative to match the gray card. I'm only commenting on the production of a gray scale, not the printing of an actual negative. Like AA said, in printing, we're trying to breath life into the final image. So, when photographing, the use of the ZS allows me (us) to get the negative densities on the film base, predictably that is, to satisfy the visualization when printing. You made a reference earlier about the "power" of visualization---I believe that power is derived by a fundamental grasp of the production of an accurate gray scale using ZS principles.
     
  23. markbarendt

    markbarendt Subscriber

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    It seems to me that if we use any given negative film, processed in a given and consistent developing regime; that a given amount of exposure, should get us a given film density at the same point on the curve every time.

    I see no reason or evidence in my own experience to suggest that I should expect inconsistent results, except for flare. So it seems to me that because of flare the actual/effective speed point for any given shot in the field would actually be the least knowable point on the curve.
     
  24. Stephen Benskin

    Stephen Benskin Member

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    Mark, I was speaking generally. It's a question of what is knowable. Zone System testing defines two points (both mistakenly). Even if they were accurately defined, there isn't any information with what goes on in between. Exposure isn't about that anyway. For black and white negative films, it's about placing the subject luminance range on a part of the film curve that will produce a quality print. There really isn't a correct exposure. That's why Zone System's EIs are usually half of the ISO and the old ASA speeds were half of the current and there's no problem in quality. The primary reasons to keep the exposure as short as possible is to keep printing times a short, limiting grain and light piping, and maximizing sharpness.

    Doremus, nicely said. I do have a conceptual problem with just black printing / proper proofs, but that's a topic for another thread. People mistakenly think I'm about extreme control. I'm not. I'm about correct understanding.
     
  25. markbarendt

    markbarendt Subscriber

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    And it is the stuff in the middle that is, IMO, the most important.

    BTW Doremus's description/use of TXP's toe is very much akin to my thought for using the shoulder in the Print Range vs Negative thread.

    These concepts fit very well with your thought, that in general, there is no right exposure.
     
  26. Bill Burk

    Bill Burk Subscriber

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    You might add shortest possible exposure helps reduce subject motion blur and camera shake blur.

    And I don't need to pay much attention to those properties when using 4x5 on a tripod.

    So I'll continue to place my shadows higher, if all the tone-reproduction theory says... is that "people accept compressed shadows, but it's not necessarily better than having detail in shadows".