Contrast Mystery (not a necessarily a problem)

Discussion in 'Darkroom Equipment' started by Rick Jones, Aug 10, 2013.

  1. Rick Jones

    Rick Jones Member

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    After a number of years happily printing with my Omega D2V condenser head I decided to run some tests (a la Anchell) with a Stouffer Step Wedge (31 step) using a new set of 6" Ilford MG filters, MG IV RC Perle, and fresh Dektol with the following results:
    Filter #2 = grade 1 (iso range # 135)
    Filter #3 = grade 1 1/2 (iso range # 115)
    Filter #4 = grade 3 (iso range # 85)
    Filter #5 = grade 4 1/2 (iso range # 65)
    No Filter = grade 1 (iso range # 125)
    My condensers are clean, clean condition Nikkor 80mm f5.6 and my safe lights have pasted the Kodak test out to 7 minutes. After reading Anchell's results with a D5 I was expecting a solid grade 2 with no filtration as well as higher iso numbers from all my filters. Not that I can't work with these uneven steps in contrast, because I have been, but am curious if other using my setup have experienced similar lowered contrast results. Could it be my paper? Purchased 250 sheet box in October 2010. Would appreciate any thoughts as to why my results were so different from Anchell's.
     
  2. MurrayMinchin

    MurrayMinchin Membership Council Council

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    While no master printer, a couple suggestions come to mind...

    What dilution, temperature, time, and agitation did you use in the Dektol?

    Why not try a developer Ilford recommends for this paper, and compare. Then try some glossy fibre base MGIV and compare again.
     
  3. ic-racer

    ic-racer Member

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    Dektol should be fine. You need to contact print the wedge to test your filter/paper combo. Then project the wedge to see how much contrast you lose to fog and flare. Could be you are having issues masking light around the negative, a dirty lens or safelight issues.
     
  4. MurrayMinchin

    MurrayMinchin Membership Council Council

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    Good point. Try putting the lens cap on the enlarger lens, and a mirror on the enlargers base. Turn off safelight and let your eyes adjust to the dark, then turn enlarger lamp on. Be prepared with black tape and to be shocked at how many light leaks there are.
     
  5. Bill Burk

    Bill Burk Subscriber

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    Does the Anchell test have you put the negative on the easel (contact test for paper range) or in the negative carrier (system test of paper + enlarger range ... which incorporates flare)?
     
  6. silveror0

    silveror0 Member

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    This is excellent advice. I've just completed some exhaustive tests with my 5x7 Omega after modifying the lamphouse to an LED source, just to see how it performs with MGIV glossy paper & MG dev (1+9). After confirming my safelight was SAFE for my typical workflow (including time in dev under the overhead safelight), and after plotting HD curves with a projected 31-step wedge for each new Ilford under-lens filter (except half-grades) from 00-5, I did this projection-vs-contact comparison as a final test, using #2 filter, and found the contact resulted in a solid increase from "grade 2" to "grade 3." My initial tests with NO FILTER in the carrier showed a smooth curve that closely matches the #2 curve (not as smooth) at high density and fell between #2-#3 curves in the mid-range. Lens was clean and tablet/carrier masking was thorough.
     
    Last edited by a moderator: Aug 10, 2013
  7. David Brown

    David Brown Member

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    I also wouldn't discount the effect of the pearl surface.