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  1. #1
    Cec
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    Gum Bichromate question

    Is it possible to make a tricolour Gum Bichromate print by using digital negatives derived by scanning a black and white print, then processing the resulting positive through Photoshop.
    This would involve the usual procedure of correcting the tonal range, reversing and inverting the image and splitting the RGB channels to provide three separate R, G and B negatives.

  2. #2

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    Your black and white print does not contain any RGB channels that you can process in photoshop.

    So example, here the Black/White column is what you get when you scan but this value can be reach with a a lot of different RGB values ( if you go continuous its an infinity numbers of value)
    R G B Black/White
    10 10 10 = 30
    0 20 10 = 30
    30 0 0 = 30


    but you can do some hand coloring in Photoshop on your B/W image and then separate the channels, print them and make a tricolor print.

  3. #3
    dwross's Avatar
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    +1 on hand coloring then channel splitting. Lots of fun. Good luck!
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  4. #4
    Cec
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    Many thanks for your replies, question answered.



 

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