Quick reflection density question

Discussion in 'Enlarging' started by Michael R 1974, Jun 12, 2012.

  1. Michael R 1974

    Michael R 1974 Subscriber

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    Hi - what is the reflection density of middle grey/zone V. I guess let's assume 18% grey for middle grey for now.

    Thanks
     
  2. Bill Burk

    Bill Burk Subscriber

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    Around 0.75
     
  3. Michael R 1974

    Michael R 1974 Subscriber

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    Just to be clear - you're talking about reflection (paper) density, not transmission (negative) density, right?

    Thanks
     
  4. Bill Burk

    Bill Burk Subscriber

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    Yes, the math is the same I think...

    Just to confirm though, I fired up the densitometer and measured the 18% gray card in an old photoguide.

    It read exactly 0.75
     
  5. Chan Tran

    Chan Tran Member

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    If it's 18% reflectance then the density is .75
     
  6. Michael R 1974

    Michael R 1974 Subscriber

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    Thanks for the help, guys.

    Michael
     
  7. Helen B

    Helen B Member

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    For reference the formula is

    Reflection Density = log10(incident/reflected)

    so for 18% it is log10(100/18)

    Best,
    Helen