Old film technique for increasing dynamic range. Does it work for digital?

Discussion in 'Beyond the Basics' started by saycheese76, Feb 13, 2009.

  1. saycheese76

    saycheese76 TPF Noob!

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    I read of a technique a long time ago in which you can increase the dynamic range of a b&w film. You calculate the exposure to expose a gray card at zone III, hold the card in front of the lens, expose, then make another exposure on the same frame at whatever you calculated for the scene. Anyone ever try this with digital?
     
  2. ksmattfish

    ksmattfish Now 100% DC - not as cool as I once was, but still

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    I don't know of any digital cameras where double exposures are possible in camera, but you could try layering exposures in Photoshop.

    This is sort of a gimmick; it may make printing easier, but won't increase the actual amount of highlight or shadow detail. You are just adding a base amount of density to the entire exposure, but if you don't get the shadow detail in the next exposure it won't be there. Instead of deep black with no details it'll be dark gray with no details. When I worked in the darkroom we made contrast masks, which offered much more control. With digital there are numerous much more sophisticated ways to increase dynamic range, including contrast masking. Contrast masking takes all day (or days) in the darkroom; it takes seconds in PS.
     
  3. saycheese76

    saycheese76 TPF Noob!

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    Thank you for your detailed response. I :thumbup:googled:thumbup: contrast masking and I'll give it a whirl.
     
  4. ann

    ann No longer a newbie, moving up!

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    i believe the D200 will allow a double exposure.
     
  5. ksmattfish

    ksmattfish Now 100% DC - not as cool as I once was, but still

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    You could just make a solid 18% gray layer in PS. Then you don't even get the texture of the gray card.
     
  6. djacobox372

    djacobox372 No longer a newbie, moving up!

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    It's likley that this only applies to film... and frankly I'd bet that it's more of a exposure trick to brighten shadows then something that actually adds detail to the scene--you may get the same results with scanned film by just increasing the brightness of the dark areas via levels and curves--something that is hard to do in the darkroom, hence the need for this old trick.
     
  7. Garbz

    Garbz No longer a newbie, moving up!

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    Indeed it's the same as playing with the curves to make the shadows not appear black. No new info is added to the exposure. Maximum dynamic range exists when you don't clip elements out of the image, i.e. exposing for the highlights on digital and slide, and exposing for the shadows on negative.
     

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