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Thread: Too many Zones?

  1. #1

    Too many Zones?

    First off, let me say that I'm not a disciple of the zone system. I'll go along with the underlying philosophy of pre-visualisation, but IMHO there are more int uitive ways of getting there. I favour incident light measurement, coupled with compensation for the specific subject to be photographed, or effect to be acheiv ed; so my question is really aimed at devoted users of the zone system.

    The reference point in the zone system (and for the calibration of exposure mete rs for that matter) is stated as being "mid grey", zone 5, or 18% reflectance. N ow 18% reflectance is only two-and-a-half stops down from a theoretical 100% ref lecting diffuse surface, which one would expect to be rendered very near flat wh ite in a print. A whitewashed wall comes close, for instance, and this isn't eve n Zone 8, so where do the higher zones fall? It seems to me that zones higher th an 8 are only of relevance if a source of illumination or specular reflection is included in the picture, and we are willing to let objects which should normall y appear near-white in the print slip down the scale to grey.

    These days, you can't even expect the film to compress the highlights by flatten ing off toward maximum density. If you look at a film like T-Max, or even Plus-X developed in T-Max developer, the density curve just keeps going up and up in a straight line, putting the densest highlights well beyond the range of the toe of the paper curve. Remembering that the zone system was thought up when a typic al film (or plate!) had an "S" shaped curve.

    The conventional zone system answer to this is to add even more zones beyond 10 to accomodate the wider density range, but how are these extra zones to be accom modated in the print? Reduced development and contrast will simply make our prin ts look flat. The only answer that I can see in reality is to burn the highlight s and/or dodge the shadows. What do you do with a contact print?

    How many users of the zone system regularly make use of zones more than plus or minus one stop from the "norm"? I'll confess that most of the time I end up exp osing within a stop of what the incident light meter recommends. How about you zone system users? I'd be interested to know how much the "expert" exposure devi ates from the idiot-guide on the leaflet included with the film (i.e. June to Se ptember, cloudy-bright - 1/125th at f/8).

  2. #2

    Too many Zones?

    It is possible to get an S-shaped curve with today's films, but not with T-Max developer. Most developers produce a straight-line curve, but some give an S-shaped curve. D-23 gives a shoulder with HP-5+ that begins around Zone 7. Microdol-X should do the same, since it is basically D-23, but with the addition of sodium chloride, a silver solvent.

    I have tested the HP-5+/D-23 1:1 combination for N-4 through N+2 development. N-4/N-3/N-2 is great for extreme contrast, which is rather common in outdoor photography. I have used N-3 to photograph architecture with one side of the building in bright sun, and the other in shade. N-2 and N-1 are great for portraits, since they lower the contrast and hide blemishes. N+1 is useful for low-contrast situations like fog. I often use N+2 for alternative processes. I would say about 30% of my shots get N development.

  3. #3

    Too many Zones?

    Pete,

    Most Zone System followers use a spot meter, not an incident light meter. Additionally, Zone System controls come into play not in the initial camera exposure settings, but rather in the subsequent development the film is given later. The initial camera exposure settings will only vary slightly for typical Zone System use, the subsequent film development will vary much more.

    At the risk of oversimplifying, the Zone System can be briefly summarized as follows: "expose for the low values, develop for the high values". The key to this is that the high values in the negative respond much more quickly to increased or reduced film development than do the low values.

    Before putting the Zone System to use, initial film testing should be done to determine your particular exposure index (EI) for the specific film/developer/meter/lens shutter combination you've chosen. Additionally, Zone System testing should be done to determine your N(ormal), N-1, N+1, etc. film development times.

    There are a ton of books/guides available describing this initial film speed test, and the subsequent testing procedures to detemine film development times, so I will not go into it here. However, a densitometer is almost a necessity to perform these tests.

    In short, you should determine the specific film EI you should use to yield a net Zone I density in your negative of between 0.08 to 0.11 (or so), so this density can consistently be reproduced in your negatives during the initial camera exposure. This film speed test should be done for every film/developer/meter/lens shutter combination you anticipate using.

    Subsequent development time tests for N, N-1, N+1, and so on, are more involved, and should be conducted taking into account your own printing equipment, light source, printing paper/print developer, personal tastes, and a whole host of other considerations.

    I'll briefly describe my own procedures for using the zone system:

    1. I will spot meter (Pentax Zone VI) a scene initially, to determine the actual range of values in the scene. This initial evaluation will tell me what I can ultimately expect when doing a more detailed and specific measurement of the scene.

    2. I'll then look at the important low values in the scene, to determine which ones should be metered, and where they should be placed on the Zone scale. This low value placement will determine my camera exposure settings.

    Let's take a typical landscape scene, with a full range of tonal values. I'll first place the important low values--those low values where I want to retain full texture/information in the final print, and not have them print as non-textured/non-detailed, blank dark areas--on a Zone III or IV.

    This will be my starting point in determining camera exposure. Often, an incident reading, taken in the same light, will yield a very similar exposure recommendation.

    3. I'll then look at the highest important values in the scene, meter them with the spotmeter, and determine where they will fall in relation to the Zone III-IV placement of the important low values.

    For illustration puposes, in a typical landscape we'll use clouds as an example of important high values. Nothing looks worse in a landscape print than a bunch of clouds that are reproduced as blank paper white. Ideally, clouds in a landscape print should have a full range of texture and subtlety.

    I'll meter the lightest sunlit areas of the clouds with the spotmeter and see where they fall in relation to my Zone III-IV placement of the important low values. If they fall at about a Zone VIII, wonderful; I can just develop the negative normally to reproduce these important high values in a satisfactory fashion. But, in a typical scene, they usually won't fall so neatly on the zone scale.

    Let's say these clouds typically fall on or about a Zone IX, maybe as high as a Zone X. This tells me that if I want to be able to retain these important high values in the final print, and not have them print as pure paper white, with no subtlety or highlight texture, I'll have to reduce the negative's development, to compress the tonal range. To do this I'll give the negative a reduced development time, N-1 or N-2.

    If the important high values fall on a Zone VII, in relation to my important Zone III-IV low value placement, then I'll have to increase the negative's development--to expand the tonal range. Constricted high values in a print will look dull and lifeless. In this case, I'll give the negative a N+1 development time to expand the high value placement from Zone VII to a higher Zone.

    4. I'll note these measurements in my records, and proceed to make the initial exposure, as per my meter's indication, for the Zone III-IV important low value placement. The only change I will make in my initial exposure will be to slightly (no more than 1/3 to 1/2 stop) increase or reduce my initial exposure settings.

    5. If I anticipate a subsequent N-1 development for the scene, I'll increase the initial exposure setting slightly, in order to maintain the low values as initially visualized/placed. If I anticipate a subsequent N+1 development of the scene, I'll slightly decrease the initial exposure for the same reasons.

    In summary, your initial camera exposure settings may not vary much, when comparing traditional Zone System practices to an incident light reading, but the subsequent development given to the negative will vary a great deal when using the Zone System.

    Hope this adds something to the discussion, Sergio.


  4. #4

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    Too many Zones?

    Pete, You are making a basic error in assuming that 18% gray is two-and-a- half stops away from maximum white. The beauty of the Zone System is that, through manipulation of development times, one can control the amount of one-stop doublings in the subject (read subject contrast range) that make it onto the limited usable contrast range of the negative. I routinely use developments that allow me put a 2 to 6 stop subject contrast range in the area between Zone V and Zone IX in the final print. Also, I routinely use N-2 to N+2 developments, and N+3 and N-3 often enough that I have calibrated them thouroughly. It all boils down to knowing what your film/paper combination will do and how to expand or contract the subject contrast range so that it will fit into the limited contrast range necessary on the negative to make an expressive print. Regards, :^D)

  5. #5

    Too many Zones?

    Pete:

    The reference zone is Zone I, the threshold of exposure, not Zone V. Zone I is really the only density on the H&D curve that has very little variation with development, thus its use as the primary reference.

    Regarding Zone V being 2.5 zones below 100% reflectance, yes this is correct, assuming both reflectances are illuminated by the same light.

    Recognize also, that 2.5 zones below Zone V is very dark (virtually black to most people), giving you 5 zones total range. Think about this: that 5 zone range is the total range you can get from a diffuse reflecting surface, like a photographic print. This fits my impression of the range of exposure that easily fits on film and easily prints.

    Where you get a greater range of zones is when different parts of your subject are illuminated by different light: a landscape with part in broad daylight, and part in shadow. The eye easily sees detail in both, but you have to compress this type of subject to fit it onto the paper. Note: paper not film. As you point out, modern films easily cover a much greater range of densities/zones, but you can't print the extreme density range straight onto paper. You are absolutely correct that the solution is to dodge and burn so that you compress.

    By the way, many modern printing papers have a long toe to accommodate the lack of a shoulder on these mondern films. End result is the same, you just do it in a different part of the process.

    For contact prints, you also dodge and burn as you need to if your negative has too great a density range.

    As far as choosing a different method other than the zone system, if it works for you, great. I have a Pentax digital spot meter that I like. I bought a selenium cell incident light meter a year ago. My battery went out on my Pentax and I didn't have a spare battery. But I had a spare meter that doesn't use batteries. They both have their uses. So does the "sunny 16" rule alluded to in your "idiot guide".

    Your message seems like you have a grudge against the zone system. If you do, it seems pointless. Many of the great photographers in the early part of the 20th century didn't use meters. What counts is results. The advantage of studying the zone system, even if you don't use it, is that it gives you a better technical understanding of practical sensitometry.

  6. #6

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    Too many Zones?

    "I'd be interested to know how much the "expert" exposure deviates from the idiot-guide on the leaflet included with the film (i.e. June to September, cloudy-bright - 1/125th at f/8)."

    Just to address your last sentence....under those paramaters....these's not a lot of deviation. The negatives created in this fashion are very printable, I have printed many 40, 50 or 60 year old negatives and they make beautiful prints. Remember when the "idiot-guide" was used, it was used for lack of any exposure meter. The suggested exposure was not arrived at by calculations and metering, i would guess it was taked from real life situations. Someone probably went out under those circumtances and exposed film made notes and arrived at the suggested times. Those times yielded and still yield properly exposed negatives.

    Now we must compensate for an "average" incident meter reading and adjust the exposure accordingly to create a negative that will be easily printable. When I use my spot meter, I am adjusting the exposure to accomplish the same end, create an easily printable negative. Different roads to the same destination. The Zone System is just that, a system. It can be very complicated, or as simple as determining your "key day" exposure as suggested by Fred Picker and that is in reality just your own personal "idiot-guide".

  7. #7

    Too many Zones?

    Pete: Your comment about there being 2.5 stops between 18% reflectance mid- grey and 100% reflectance is correct. However, this does not describe the full tonal range in the scene. One needs to consider that not all objects in the scene receive the same illumination. It is the variance in illumination times the reflectance of each object that gives rise to the complete tonal range in the scene. Taken together the intensities of light reaching the film from the various objects in the scene can cover a very wide band of values - in theory an unlimited number of zones - but in most daylight scenes the tonal range will be within a 5-10 zone range. Dave

  8. #8

    Too many Zones?

    Dave hits the nail on the head, and also identifies one of the major differences between outdoor incident and reflective metering. Almost no flatly illuminated subject has a brightness range of more than five stops. However, in full sunlight, the difference between a gray card in full sun and one in full shadow is four stops; with very deep shade (e.g. heavy woods) the difference can be more than five stops. Thus, a typical nature scene in full sunlight will have a total brightness range of 10 stops, even though the subject brightness range is only 5 stops.

    With regard to the question about careful measurement versus sunny 16, it is useful to remember that Ansel Adams developed the zone system as a teaching tool to explain exposure to students -- most of his own great photographs were made without it. In fact, once you are used to a particular environment and film, much of the time careful measurement with a spot meter or use of an incident meter with something like Davis's Beyond the Zone System will lead to exactly the same exposure as no meter and experience. For example, if it is June in Alaska, a sunny day between 8am and 8pm and I am shooting a landscape with mountains in the background and forest in the foreground, I don't need my spot meter to tell me to expose HP5+ with a Wratten 12 filter at f/22 for 1/50 and develop 12 minutes in PMK. When I was learning, I did need the whole system.

  9. #9

    Too many Zones?

    Of course Ansel used the zone system before he invented it--it is nothing more than applied sensitometry. Who doesn't do that? (not counting idiot guide usage).

  10. #10

    Too many Zones?

    Thanks for the responses.

    To clarify things slightly: What prompted the question was my own experience in attempting to apply the zone system to exposure control some years ago. On numerous occasions then, and since, I've attempted to be "clever" with metering and exposure control, only to arrive back at more-or-less the same old exposure value that a simple grey-card or incident reading, or even the "idiot guide" would have given me.

    I've also just been reading a book called "Perfect exposure" which strongly advocates the zone system, (with zones up to 12!). However, a lot of the illustrations, while undoubtedly being good pictures, are admitted to be the result of luck, mistake, guesswork or bracketing. Adams himself, in "The Negative", frankly admits to getting unprintably blocked up highlights in at least one example, and having to resort to dodging and burning in order to print some of his negatives.

    Those respondents who were honest enough to own up to it, have so far confirmed my suspicion that, in the majority of cases, the application of complicated methods of exposure determination are largely a waste of time. Note: I'm not saying the same about control of the development process, although this raises the moot point of whether the zone system has any application in colour work, with its far less flexible processing.

    I didn't have any grudge against the zone system when I posted this question, but some of the patronising responses of its proponents are making me lean that way. :-) Can I point out: (i) that you don't need to know anything about the zone system to know something about sensitometry and densitometry. (ii) that 18% of a pure white reflector is -2.5 stops (-2.474 stops actually) no matter what development you give it. (iii) That Adams devotes 3 pages of the section on exposure in "The Negative" to defining and emphasising the importance of zone 5 as a reference, and only touches on the use of zone 1 in the section on development. (iv) that, yes, "pulling" development does allow a wider range of subject brightness to be encompassed on a given grade of paper, but micro contrast and acutance are degraded. (v) that multigrade papers have opened up numerous possibilities not even dreamed of when the zone system was invented. (vi) that conventional wisdom should always be challenged from time to time. (vii) that the use of roman numerals isn't very space efficient.

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