Bleach Bypass

Discussion in 'Color: Film, Paper, and Chemistry' started by jd callow, May 29, 2006.

  1. jd callow

    jd callow Moderator Staff Member Moderator

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    I am going to begin some bleach bypass experiments. I have read some information on the internet and exchanged information with Poco and PE regarding the process.

    There is a lab in Europe that does this for the Cine industry and there results run from subtle to spectacular, but always interesting. Unfortunately their process is a guarded secret.

    What i've learned prior to doing it:
    • Slow film may be better because it has less silver to start with
    • Bleach works quickly
    • Bleach works through the layers so a partial bleaching (pulling the film prior to completion of the bleach step) may mean that the top layers have been bleached, but the inner layers may not. This might aggravate colour correction and or may be the key to controlling overall density.
    • A very dilute bleach may be better than a partial bleach
    • Lower contrast film may be more printable than higher contrast films or scenes.
    I would welcome any other ideas, experiences or examples.

    As I go forward I will report back.

    Cheers,

    jdc
     
  2. Kino

    Kino Member

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    Beach Bypass for cinematography has been extensively written about on the CML; Cinematographers Mailing List. Although it is for motion pictures, you should get some tips from the discussions

    http://www.cinematography.net/Pages GB/BLEACH.HTM
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    JC;

    You have all of the essentials correct.

    Fix only with no bleach is the highest level of silver, then partial bleach and fix or dilute bleach and fix are next in order of effectiveness.

    Good luckl

    PE
     
  4. df cardwell

    df cardwell Subscriber

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    OK, so I'm thinking all kinds of unnatural thoughts.

    Is there any reason we couldn't just fix a roll of film,
    then - using dilute solution - bleach for various times to measure and test the effect ?

    d
     
  5. jd callow

    jd callow Moderator Staff Member Moderator

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    Don,
    This sounds like an excellent testing method Dev + Fix then snip and test 0 Bleach, 5% Bleach, 10% bleach, etc...

    I am also going to combine pull processing to lower the contrast of the film, hence the other thread asking for standard pull times for c41.
     
  6. Photo Engineer

    Photo Engineer Subscriber

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    JC;

    IDK standard pull times, but when I make internegatives, I find that 2' 45" or 2' 30" gives about 1/3 or 1/2 stop pull with a nice reduction in contrast. This might be helpful to you in this stragegy.

    PE