Printing Middle Gray at specified exposure, Does this logic make sense ?

Discussion in 'B&W: Film, Paper, Chemistry' started by lhalcong, Jun 4, 2013.

  1. lhalcong

    lhalcong Member

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    Lets say I have determined the exposure - Time @ F/Stop to print middle gray (density measured in the film) as acceptable middle gray on the chosen paper. Any other zones that exist in the picture will fall where they fall assuming the film is exposed and processed correctly as per one wishes. Having determined that, will I ever need to run strips again.?

    Assumptions:

    -Assume I have determine this exposure factor for a particular type of paper and film combination with my Enlarger. (I know changing the type of paper may need a change of exposure as well).
    -That I shoot a middle gray card in the same type of lighting where I will shoot the rest of the pictures.
    -That the rest of the zones in the pictures have already been determined to be proper in film and processed correctly during development.

    In this case I run only one strip on the first frame where I shot the middle gray card, once I have this exposure correct, the rest of the pictures can print at this same exposure and all will be correct. Does this logic make sense ? ultimately saving paper. Even if I want that middle gray zone to be a little lighter or a little darker, I have determined what exposure I need by running the first strip. or even take it a step further and say I already know those times from one test and all films I shoot from now on will abide by this factor.

    Do I make sense ? will this logic work ? if not, where may this brek down if you think it is incorrect ?


    thanks in advance,
     
  2. Tom1956

    Tom1956 Inactive

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    It's a start. Now if you can get that darned logic to cooperate. But certainly it's a good plan for getting in the ballpark.
     
  3. markbarendt

    markbarendt Subscriber

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    Yes.

    Pegging exposure in camera and enlarger can get you reliable results.
     
  4. Michael R 1974

    Michael R 1974 Subscriber

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    A standardized print time for middle grey is a reasonable approach for getting you in the ballpark but not necessarily a formula for making all your prints with the same base exposure. There are too many variables that would all have to fall into the same place for every image. It assumes identical metering and exposure decisions, identical flare conditions, subject contrast etc. etc. For example, when you meter an object and expose it for middle grey, do you always want the metered object to be middle grey in the print? Is that always going to be the optimal exposure? What about all the other values in relation to the metered value?

    Standardized exposure times are only points of departure. You'll still have to use your eyes and creativity to make adjustments.
     
  5. Bill Burk

    Bill Burk Subscriber

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    Sometimes I think it is only my unwillingness to use light modifiers (scrims, fill light) that makes me need to do test strips.

    No, you will always need test strips. It is not bad to strive to make good negatives and try to standardize, but the negatives you get will vary from what you planned for millions of reasons.

    Unless you carefully control the light.
     
  6. gzinsel

    gzinsel Member

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    for me, I dev. and fix , , etc an unexposed sheet of film, to determine base + fog. then placing that neg. in the neg. carrier, raising the enlarging head to the height of any particular degree of enlargements ( usually for me its the same as always, full neg on 8x10 or 11x14). I make test strips for each paper grade to find maximun blackness. at each intervel moves i note the time, when no longer I can distinquish any niticable difference after fix and dry down. I Now have a starting point for time. However it is just a starting time. Ie. One neg may have been shot( exposed) higher or lower on the curve! some negs were over developed, some under dev. and, of course, some "just right"!! different grades, different choice of developers, different dilutions, differing temp and of course time. all inter relate. its all very fluid. I can not say, "that I have a standard time" for exposure of paper, even though I use the same film, and developer combo, all the time.
     
  7. piu58

    piu58 Member

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    I work another way. There always exist an minimum time for maximal black. If you are below that time, you never get a full black in your image. I use this time as a starting point. The middles and especially the highlights fall where they want. Changing the contrast of the paper I bring the highlight where I want to have them. With that exposure time / contrast level point I begin the fine tuning of the print: Slightly changes in time, dodging, burning and so on.