Question about metering shadows and highlights

Discussion in 'Exposure Discussion' started by welly, Mar 7, 2012.

  1. welly

    welly Member

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    Hey all,

    Got a rather schoolboy question but it's been something on my mind for a while as I try and improve my metering methods and get better exposure.

    Shooting black and white negatives - I (spot) meter for the darkest part of the scene I still want to see detail in, which will sit in zone 3. That's fine. And then I understand I need to get a reading of the highlights so I can use this information when I develop the negative and make any adjustments necessary.

    If I meter for the shadows and get a reading of say f/16 at 2 seconds and then to put this into zone 3, this works out to f/16 at 0.5 seconds. I then meter for the highlights and get a reading of f/16 at 1/250 second. To then get the scene brightness range, I have my reading for the shadows and reading for the highlights. However! For the shadows, am I using the reading the meter gave me or the value I'm working with to put the shadows in zone 3?

    Ie. am I using the 9 stop difference between the metered readings (f/16 at 2 seconds to f/16 at 1/250) or the calculated 7 stop difference (f/16 at 0.5 seconds to f/16 at 1/250) to get my scene brightness range?

    Thanks very much!
     
  2. ic-racer

    ic-racer Member

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    Use multigrade paper and forget about the highlight reading. Adjust the contrast during printing, rather than film development.
     
  3. welly

    welly Member

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    Thanks for the tip. At the moment, I'm printing with inkjet and I guess I can adjust in Photoshop (if needs be). When room for a darkroom allows, I'll certainly take onboard your advice and try it out!

    Aside from that, is there anything else you can suggest to getting a correct exposure or am I good metering for the shadows? Or metering for whatever my main subject is and putting that into the relevant zone?
     
  4. markbarendt

    markbarendt Subscriber

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    Dunn and Wakefield, Exposure Manual

    Get as Late a version as you can.
     
  5. CPorter

    CPorter Member

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    In ZS practice, the luminance ratio would be determined between the "placement" of the desired shadow luminance and the "fall" of the desired highlight luminance. Making the shadow "placement" sets the gray scale so to speak, because all other luminances fall on the gray scale relative to your "placement" of the desired shadow area. In your example, the way I see it, you have a luminance ratio of 128:1 between Zone III and Zone X.
     
  6. Bill Burk

    Bill Burk Subscriber

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    Hi welly,

    9 stops is pretty long range, we have some people here who "live" in that territory. I hardly ever get meter readings over 4 stops range and I have to pretend there is something darker and lighter so I can admit my picture is Normal.

    You use the whole 9 stops in your example.

    But maybe you are pointing the highlights at something that isn't important. There are going to be things in your picture that are darker than your darkest meter reading. These are supposed to fall into blackness, like open doors. And the spectral highlights, things that reflect the light like mirrors and chrome, are supposed to go off into pure white.

    If you really have 9 stops, then you might use N-2 development in classic Zone System parlance. Or you might do as ic-racer says and ignore it and make up the difference with Multigrade Paper which these days is pretty remarkable.

    But I am guessing you might be metering something that is irrelevant. Point at the most significant shadow, point at the most significant highlight. Leave some room for some things to be darker and lighter.
     
  7. welly

    welly Member

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    Hey Bill,

    That was just an example off the top of my head but actually gave me something to think about with such a wide range and that you're probably correct - there's some parts of a scene that are probably not worth considering. I guess part of me, coming from a digital background, has had never blow the highlights! beaten into me time and time again.

    Cheers!
     
  8. David Allen

    David Allen Member

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    Hi Welly,

    You are quite correct that, with digital and transparencies, the key 'rule of thumb' is to avoid highlight blow-out.

    With negative materials the converse is true - you need to expose for adequate shadow detail.

    Personally, I meter the shadow area where I wish to retain shadow detail and place this on Zone III. I then develop using a two-bath developer (Barry Thornton's is very good, very simple, has only a few chemicals and is easy to make) which ensures that I retain highlight detail irrespective of subject luminance.

    Best,

    David
    www.dsallen.de
     
  9. RalphLambrecht

    RalphLambrecht Member

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    use the metered difference to get the brightness range
     
  10. CPorter

    CPorter Member

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    Just wandering what N-2 would accomplish.

    Just summarizing the example here, a reduction in exposure from 2 sec at f/16 to 1/2 sec at f/16 is a two stop reduction-------if 1/2 sec at f/16 is a Zone III shadow placement (as stated in the example), then this makes 2 sec at f/16 the Zone V metered value. The 9 stop range mentioned is from Zone V to Zone XIV. Living there and printing it successfully (I realize "successfully" is a subjective thing here) I guess are two different things. This is a very high shadow placement, that, given the contrast of the light, can push even non-specular high values pretty high up there, so what will N-2 accomplish? Not much that I can tell. Let's assume the specular values are at XIII and above in the example, that still leaves a Zone XII luminance needing N-4 to get to a density that will render respectable texture on the print surface, N-3 to render it with some definite tone below paper white.
     
  11. Michael R 1974

    Michael R 1974 Subscriber

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    Welly, unless you are planning to place your shadows on zone V, the easiest method is to meter your shadows and highlights before placing your shadows. That makes it easier to determine the spread. So, for f16 you meter your shadows at 2s and highlights at 1/250. Now you know your spread (9 stops). Then simply place your shadows and count nine zones up from there to determine where your highlights will fall with normal development. In your case, zone III for shadows puts your highlights on zone XII.

    I am very often working with very long luminance ranges when I photograph. And I would warn, as I have done in many other threads, against using the zone system too "rigidly" under these circumstances. Assuming the highlights you metered are not specular and you want to render them with detail, the zone system math says N-4 development.

    I caution people to do a more thorough evaluation of the scene, and how they want the final print to look before making that decision. I'm refering to wet printing here, but the principles still apply. Simply developing to bring bright highlights down to zone VIII does not necessarily mean they will have detail in the print. It means only that the scale of the negative will fit onto the paper without manipulation. That is not the same thing at all. Zone VIII on the paper will only have detail if it is in the negative.

    Where long luminance ranges are involved, the relationship between what is in the negative and the scale of the paper is fundemantally misunderstood by many zone system users.
     
    Last edited by a moderator: Mar 8, 2012
  12. Bill Burk

    Bill Burk Subscriber

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    Hey CPorter,

    I owe your plumber big time! I put in a vent and now my darkroom sink drains every time.

    You and Michael have hit the nail on the head. A scene that meters 9 stops difference between important shadow and important highlight might need to be treated in the darkroom like it has 10 or 11 stops.
     
  13. andrew.roos

    andrew.roos Subscriber

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    USe the two meter readings, without any adjustment for zone placement, to determine the contrast range.
     
  14. jp498

    jp498 Member

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    I'm shooting from the hip in regard to zone system. I don't spot meter, but do consider the shadows and what level of detail they should have in the final image and that affects exposure choice, just like the OP. I use tmy2 and don't worry about the highlights because the film can capture it.

    Then for a big-range scene, I develop it in PMK with has some nice compensating treatment of reining in the highlights.

    A scanner or VC paper can handle this with some modest flexibility. Zone system predates quality variable contrast paper (or scanners) and film like tmy2, so it was not so optional in it's time. Regardless, there is much value to having the negative as ideal as possible.

    Scanning can pull a huge amount of data out of shadows, but it's still nice to not let things be too weak.
     
  15. Michael R 1974

    Michael R 1974 Subscriber

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    Actually I think I'm saying the opposite.
     
  16. CPorter

    CPorter Member

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    Bill, i'm at work now and thought about my post way early this morniog. If you were meaning n-2 after considering a zone III shadow Placement (I'm sure you were), then i agree with -2. Seven stops from that is a high value of X I assume then, that it is a desired high value that -2 Will develope to a zone 8 Negative density for better printing. I was considering the very high zone v placement only for some strange reason in my post
     
  17. welly

    welly Member

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    Thanks everyone for your very useful advice and suggestions. You've given me plenty to think about! At this point I'm not printing in a darkroom and am just scanning/inkjet printing so I guess I've got room for a bit of manoeuvre, however I'd like to get the technique correct and understand exactly what I'm doing rather than just throwing darts blindfolded and fixing up later in photoshop! It's not what I got into film photography for :smile:
     
  18. CPorter

    CPorter Member

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    Awesome for you, glad to hear your plumbing is working good.
     
  19. CPorter

    CPorter Member

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  20. Doremus Scudder

    Doremus Scudder Member

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    FWIW, I find it cumbersome to take a Zone V reading and then subtract two stops to find Zone III. See if you can find a Zone dial/sticker for your meter. There are some available for free download on Ralph Lambrecht's Darkroom site. A Zone dial will allow you to place the Zone III (or whatever) value and then easily see where the other values fall.

    If not, I would set my meter's ISO two stops higher than the film is really rated so I could just point it at an important shadow and get a Zone III reading at least. You will then have to count stops to find where the other values fall, but you can do that on the fingers of one hand most of the time.

    As for ic-racer's method of just using VC paper; if you choose to do this, I would advise that you standardize on a bit less development (i.e., less-contrasty negative and use the VC to build contrast. VC papers at low contrast (e.g., 00-1) have some evenness problems in the middle values (loss of separation at skin-tone value, etc.). These go away above about 2-2.5.

    For me, I have development schemes that go from N-4 through N-2, although I too, use changes in paper contrast and figure that in when determining development.

    Best,

    Doremus

    www.DoremusScudder.com
     
  21. Klainmeister

    Klainmeister Member

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    Film choice and developer also will play a role. If i had a very wide range, I would develop using a two-bath method which I have reached 13 stop latitude with (Fuji Acros, Pyrocat split bath) and for normal scenes with 8 or less stops, I just expose slightly under the average to maintain shadow detail and have no issues with it thereof. Check out my BW Kiva shot for an idea about what split development can do.