CTO in Place of 85B Filter

Discussion in 'Color: Film, Paper, and Chemistry' started by E76, Jul 5, 2009.

  1. E76

    E76 Member

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    I have quarter, half, and full CTO gels along with bunch of tungsten slide film I would like to use outdoors, but no 85B filter. Is it possible to use a CTO in place of an 85B? What kind of results can I expect? It seems like it might work, but I cannot be sure.

    Thanks.
     
  2. JBrunner

    JBrunner Moderator Staff Member Moderator

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    Color wise the CTO will work fine. Optically it will depend on how good the gel is and where you put can it.
     
  3. OP
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    E76

    E76 Member

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    Any idea as to what the required exposure compensation with any of the CTO filters would be? So far I have found conflicting sources of information stating that a full CTO is identical to an 85B (+3/4 stop) and others saying a full CTO is actually warmer than an 85B, meaning the correction would be closer to +1 stop, if not more. 1/3 of a stop can make a big difference with slides!
     
  4. AgX

    AgX Member

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    From the curves I've got I deduce that a full CTO is identical in filtration to a 85B (a 1/2 CTO would be a 85C).
     
  5. Peter Markowski

    Peter Markowski Member

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    Hold a ambient meter under the gel then without, and note the difference for your stop compensation.
     
  6. DanielStone

    DanielStone Member

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    just meter through the gel before you expose, making sure to put the gel back over the lens though, as i inadvertently didn't yesterday, ooops. it'll be alright, slides will be a little bluer than i'd like, but the kodachrome should manage alright

    -dan
     
  7. OP
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    E76

    E76 Member

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    That's exactly why I don't want to do that. :tongue:

    Thanks for all the help guys!