Dmin of paper

Discussion in 'Color: Film, Paper, and Chemistry' started by uma, May 14, 2004.

  1. uma

    uma Member

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    hello
    i want to know method to check Dmin of paper and how it affects quality of photo.. I would also like to know the difference between Kodak and fuji paper

    uma
     
  2. ann

    ann Subscriber

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    Just to clarify your questions, why would you want to print to the Dmin of the paper rather than the Dmax?

    And, secondly I don"t think Fuji makes a black and white paper, unless it is a very new product.
     
  3. Donald Miller

    Donald Miller Member

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    The dmin of a paper is determined by taking a reflective densitometer reading of the paper base white (no exposure). The dmax of a paper is determined in the same manner.
     
  4. lee

    lee Member

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    dmax is the black part of the paper so read that like Donald says.

    lee\c
     
  5. Thilo Schmid

    Thilo Schmid Member

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    Since this was posted in the color category, I assume that Dmin was actually meant. Dmin variances of color paper could be determined with a B/W densitometer whereas any density of color paper should be determined with a color densitometer. A B/W densitometer might be fooled, depending on its spectral sensitivity (same problem occures with pyro stain).

    Although Dmin is usually defined as the paper base, you may also zero your densitometer on the brightest paper you have and measure relative differences to other papers. However, I do not expect that they lie beyond the second decimal and thus not within the significant measurement range of usual photographic densitometers.

    More interestingly is usually the difference between Dmin before and after development (resp. in comparison with an unexposed and fixed sheet). While the paper ages and the developer wears or the temperature gets higher, Dmin increases and this can vary between different makes. I found that Fuji Crystal Archive is usually more invariant to these parameters than other papers. And to me, all modern papers have the same white base, obviously including some kind of "brighteners".
     
  6. ann

    ann Subscriber

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    oops. didn't notice the major topic. sorry :surprised:ops: