How to do a zone test on sheet film

Discussion in 'B&W: Film, Paper, Chemistry' started by rmolson, Feb 11, 2009.

  1. rmolson

    rmolson Member

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    I have heard such good reviews of Freestyles EDU sheet film which is Forma 200 I decide to give it a try. But being cheap by nature and circumstance, shooting dozens of sheets 4x5 film to find my zone I and VIII makes me wonder if there isn’t a better way . I considered exposing for Zone I with the 4xz5 sheet film holder in the camera and then slowly sliding the dark slide down effectively masking the previous exposure and repeating the same exposures thus creating Zones II ,III,IV etc. However I remembered something from my old days of color separating and masking that accumulative exposures did not produce linear density changes. Assuming no flare (good luck) the second zone I exposure would not necessarily produce a Zone II density equal to a separate zone II density exposure etc.
    Not only that but it is still winter and shooting outdoors in sunlight is pretty much months away!
    Anybody have any experience or ideas on this?
     
  2. MikeSeb

    MikeSeb Member

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    I'm with you dude/dudette! I don't have the attention span to see me through it. To me the benefit of rigid Zone-System testing is as much the controlled methodology and record keeping it requires as it is the actual exposing and developing. I think if you exercise the same care in your ordinary for-keeps metering, exposing, and processing, you can get there through a thoughtful trial-and-error method.

    By this I mean you have to carefully control variables like development time, temp, and agitation; be consistent in your metering practices; and keep good records of what you do so you can adjust while knowing where you started and how you got a given result the last time. I do this whenever I change film or developer (which is much less frequent now that I'm an old codger); I shoot at box speed or a half stop slower depending on my intended developer's reputation for speed-preservation (d-76 ad xtol give full speed, hc-110 does not, IME); develop at mfgr's recommended time, evaluate, adjust on the next roll. It rarely takes me more than 3 rolls to get it pretty much locked. It helps that I do my processing in a Jobo, so temp and agitation are always the same.

    I am ramping up my 4x5 shooting so I'll be doing the same with sheet films. Whether I will have expended the same number of sheets with my trial-and-error method than with formal zone testing is unknown; but even on the ones that aren't perfect I am usually close enough to get a usable image.
     
  3. Nicholas Lindan

    Nicholas Lindan Advertiser Advertiser

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    For normal exposure times there will be no problem.

    The effect is due to the same mechanism than causes reciprocity failure - as long as you are out of the range of reciprocity effects (1 second to 1/1000 second) the exposures will add like you expect them to.

    I have done 'zone system tests' where I push the darkslide in 1/2" between exposures. The exposure sequence is f22, f22, f16, f11, f8 or the equivalent shutter speed sequence 1/500, 1/500, 1/250, 1/125, 1/60 ...

    The easiest way to do the test is to contact a step tablet.

    Very bright short exposures, like flash pops, don't add linearly. Very dim exposures are also a problem if they are interrupted for too long - the silver halide crystals have to get hit by a threshold number of photons within a certain time period to activate, if the time between photon hits is too far apart then the effect of earlier photons fades away without activating the silver.
     
  4. mikebarger

    mikebarger Subscriber

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    I followed Fred Picker's procedure for sheet film testing for EI and development time.

    It works well.

    Mike
     
  5. drpsilver

    drpsilver Subscriber

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    11 Feb 2009

    Rmolson:

    I have done the same thing as Nicholas with very good results. I find a place that will give me a Zone I exposure that would not be effected by reciprocity and create a "step tablet" of unexposed, Z0.5, ZI, ZI.5, ZII, ..., ZIII or III.5. Determine my exposure index, then do a complete "characteristic curve" at that EI.

    Hope this helps. Good luck.

    Regards,
    Darwin
     
  6. 2F/2F

    2F/2F Member

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    You don't need to shoot all that many shots. Seven for the working EI test. A handful each for normal, plus, and minus development. You can do all three tests with a 25-sheet box of film, which costs $13. Believe me; the time spent doing all the developing is worth more than $13, so I wouldn't worry about following the standard test procedures.
     
  7. Doremus Scudder

    Doremus Scudder Member

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    Attached is the method I have developed and used for Zone System calibration. It uses a minimum of film and time. It does suffer from the intermittent exposure effect, but this is minimal and usually insignificant if you keep the shutter speeds used in the test above half a second or so.

    It looks complicated at first, but is easier done than said.

    BTW, this is my copyrighted stuff, so please use it for non-profit, personal purposes only.

    Best,

    Doremus Scudder
     

    Attached Files:

  8. rcoda

    rcoda Member

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    You can do this using ND filters, to keep aperture and shutter speed consistent. The way I was taught (by Rod Klukas) you can do a N determination on a couple of sheets of film ( 2 per sheet). The I discovered if you use an old holder with a few extra slides, you can cut a 1/2-3/4" hole in four positions (one per slide, all on one side [L or R] in different positions top to bottom) and do it all on one sheet of film.
     
  9. GeorgesGiralt

    GeorgesGiralt Member

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    Hi !
    If you want to be cheap on film and save time for dev. use a dark slide with holes.
    You have to get 5 sheet of plastic, metal or whatever is able to stop light, and line up one hole on each evently spaced on a sheet of film splitted in half.
    You do all exposures on one sheet of film, changing dark slide between them. This way you'll have 5 spots on the half sheet. reversing the slide provides for 5 more exposures patches.
    hope this helps.
    BTW I did not invent this myself. I read it somewhere.
     
  10. Richard T Ritter

    Richard T Ritter Member

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    Get the book "Finely Focused" http://circleofthesunproductions.com/ and follow the exercises. The test can be done in your own darkroom no need for a densitometer reading of the negatives. I have run the test as written in the book and then checked then against with a densitometer and they were right on.
    The tests as written in "Finely Focused" are easier to follow then what Fred Picker wrote in the "Zone VI Workshop" book. But the book is worth read.
     
  11. jgjbowen

    jgjbowen Member

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    I would second Richard's recommendation of "Finely Focused"
     
  12. Bruce Osgood

    Bruce Osgood Membership Council Council

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    OP
    rmolson

    rmolson Member

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    Thanks for the information Mr Scudder


    I was a little skeptical of your method, I had calibrated before but never with sheet film. But the negatives were dead on! Thanks for sharing the information.