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  1. #21
    ic-racer's Avatar
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    I wanted to do the tests anyway, to understand a little more what's happening
    There are a lot of ways to do the tests. This way is based on sound principles and is pretty easy to do and to understand: Do a Zone I one exposure test at various ISO/ASA settings and keep good notes, and process the film. Place the processed and dry negatives of zone I over your meter. The one that drops exposure by 1/3 stop over unexposed film base equals 0.1 log d and that is the one to base the speed on. Next, using the speed you had just determined, you can shoot a zone VIII target. Do that on three rolls. Process the first roll for your usual time. Place the zone VIII negative in the enlarger so you can also see the film edge. Do a test print so the film edge is just black. Now the Zone VIII should be just off-white, very slightly gray. If it is totally white, then process the next roll for 25% time less and repeat the test. If the Zone VIII is a darker gray, then increase development 25%.

  2. #22
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    Quote Originally Posted by Tofek View Post

    For the fog however, I don't see why there should be more fog on a field exposed as zone 0 than on a field which received no exposure ( lens cap on ) ? That's the case in my test, and it proves that the light meter didn't give me zone 0 exposure (respectively zone V) but a little more (overexposure). Isn't that correct ? I'm trying to understand...

    Thanks for the replies guys
    If there is no image bearing detail in your "fog" it sounds to me that you are experiencing one of two things:

    1) you have problems with flare in the system; or
    2) your "fogged" area was essentially subject to a below threshold amount of light before the exposure, and the additional Zone 0 light bumped it up over the threshold.

    Is there any chance we are thinking of "fog" in two different ways?
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  3. #23

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    Pardon my asking, but the meter reading assumes that the shutter speeds are accurate. If the shutter is running slow, you could be getting image density for Zone 0, not fog. Have you checked the shutter?

  4. #24

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    Ic-racer, that's basically the test that I did, except for the measuring of density with light meter (I did it by looking at zone 0 which should have no density) and for the zone VII (I used zone IX to determine the dev time).

    Matt, yes that's possible. In fact I meant density, not fog. These are two different things, right ? Your 2) point is what I think is happening, that zone 0 received light when it shouldn't have.

    Silveror, shutter speed were checked a year ago so they should be ok.

  5. #25
    ic-racer's Avatar
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    Quote Originally Posted by Tofek View Post
    (I did it by looking at zone 0 which should have no density) .
    Be careful! Zone 0 is the film density resulting from one stop of exposure less than zone I exposure. Its density is not defined. You don't want to base anything on its density value. It is NOT defined as zero exposure or zero density on film.

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