Film Speed Test - Enlarging & Contact Printing

Discussion in 'B&W: Film, Paper, Chemistry' started by Sanjay Sen, Feb 15, 2011.

  1. Sanjay Sen

    Sanjay Sen Member

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    Hi All,

    If I am doing a film speed test for a particular film that I use in 4x5 (enlarging) and 8x10 (contact printing), will the same speed test (say on 4x5 film) suffice for both purposes as long as I am using the same paper, developer and light source combination? Or will I need to do separate tests for negatives destined to be enlarged, versus those destined to be contact printed?

    If you believe separate tests will be necessary, I would appreciate it if you'd explain your reasoning as well.

    Thanks in advance for your help with this.


    Regards,

    Sanjay
     
  2. Stephen Benskin

    Stephen Benskin Member

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    I all depends. Technically, the requirements for contacting and enlarging will probably be different. Of course, the best way to tell is to test each printing situation to determine the negative requirements. The correct processing would be to adjust for each condition. On the other hand, if you are using a diffusion light source, the differences will be small and it isn't really necessary to do individual film testing unless you simply like the extra control.
     
  3. Sanjay Sen

    Sanjay Sen Member

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    Currently, I use a Ilford Multigrade 500H enlarger head for both enlarging 4x5 (and smaller) negatives, as well as contact printing 8x10 negatives, if that helps with answering the question. Since I have a very limited time for photography, I would like to do the basic tests, but wouldn't want to do very extensive testing.
     
  4. Anscojohn

    Anscojohn Subscriber

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    As above, theoretically they should be different when one uses a condensor light source for enlarging. I once had a T-shirt made which read BEWARE OF THE CALLIER EFFECT!! It has to do with the scattering of light in the denser part of a negative when the light going through it is collimated, so the fact is that the high tones might need different density in a negative to be enlarged rather than a negative which is contact printed.
    I am willing to be money (a small amount, to be sure (vbg) that if your Ilford head is a diffusion light source, you shall not find a noticeable difference if the negative densities on your 8x10 neg measure the same as your 4x5 neg. My two cents.
     
  5. ic-racer

    ic-racer Member

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    Are you using the same lens and shutter and meter? If so, then you should not need to repeat the exposure index test with the two different formats of the same film.
     
  6. Sanjay Sen

    Sanjay Sen Member

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    Different lenses, hence different shutters, but same meter.
     
  7. jp498

    jp498 Member

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    Since you are using the same enlarger, I'd consider things the same. I'd say shoot things as if you are going to enlarge them. The only difference I see is that the negative is above the enlarger lens in one case and below the lens in the other case. Unless your enlarger lens is real bad (lacking contrast, dirty, moldy, and separated), you will not have much of practical difference.
     
  8. mike c

    mike c Subscriber

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    Have the shutter speeds checked and or corrected,would help alot to get to a ball park personal exposure speed for the film you test.I recently tested all my shutters and was surprised at the difference between them.For me it was a good starting place.

    Mike