In-Camera Color Separations

Discussion in 'B&W: Film, Paper, Chemistry' started by wildbillbugman, Dec 31, 2009.

  1. wildbillbugman

    wildbillbugman Member

    Messages:
    819
    Joined:
    Apr 18, 2005
    Location:
    San Bernardi
    Shooter:
    8x10 Format
    Hi,
    Anyone doing In-Camera Color Separations ? If so, I would be interested in which film you use. Ilford FP-4 has been suggested, also Kodak Tri-X.
    Regards,
    Bill
     
  2. tiberiustibz

    tiberiustibz Member

    Messages:
    1,749
    Joined:
    Oct 22, 2007
    Location:
    Tufts Univer
    Shooter:
    35mm
    I used HP5+ and it worked fine. Your film choice shouldn't matter too much. Just don't use a film with reduced red sensitivity like Efke 25.
     
  3. wildbillbugman

    wildbillbugman Member

    Messages:
    819
    Joined:
    Apr 18, 2005
    Location:
    San Bernardi
    Shooter:
    8x10 Format
    Nicholas,
    I have been told that most modern films display a non-linier curve in the Green. I haven't looked at the data on HP5. Do you use any color correction filters when doing your separations. Or just the three cut-off filters.
    Which gree.do you use.
    Bill
     
  4. tiberiustibz

    tiberiustibz Member

    Messages:
    1,749
    Joined:
    Oct 22, 2007
    Location:
    Tufts Univer
    Shooter:
    35mm
    I used theatrical filters and digital methods, simply to see if I could do it. The results had colors, and that was about all I intended to prove. The filters you would use given a critical project are the corresponding wratten filters. They appear to be Wratten 47 (blue), 25 (red), and 58 (green). And btw those are not cheap. What is the intended purpose? With any analog methods you need registration systems to line everything up lest you be plagued by fringing. You might also try looking up the filters used for dye transfer printing or googling color seperation filters.
     
  5. sanking

    sanking Member

    Messages:
    4,813
    Joined:
    Mar 26, 2003
    Location:
    Greenville,
    Shooter:
    Large Format

    I made a lot of in-camera separations in the 80s and 90s and have made a few as late as this year. Any film will work but you really want one that has a very straight line linear curve. Both FP4 and TRI-X are very bad choices in my opinion as neither has the kind of curve that is best for separations.

    My advice would be Tmax-100 or TMY 400. Both are characterized by very long and linear straight lines, in R, G and B. There may be other films that will work for you OK, but these two would be my first choice.

    Sandy King
     
  6. 2F/2F

    2F/2F Member

    Messages:
    8,004
    Joined:
    Apr 29, 2008
    Location:
    Los Angeles,
    Shooter:
    Multi Format
    I agree wholeheartedly. T-Max 100 is my favorite film for this. FP4 is a hair wonky. I liked Acros too, but only tried it once because a few Quickload sheets were let over from a shoot.
     
  7. 2F/2F

    2F/2F Member

    Messages:
    8,004
    Joined:
    Apr 29, 2008
    Location:
    Los Angeles,
    Shooter:
    Multi Format
    P.S. One film I really want to try for this is Ilford SFX, just based on its spectral sensitivity chart published by Ilford. It appears to respond nearly equally to all visible colors of light.
     
  8. Photo Engineer

    Photo Engineer Subscriber

    Messages:
    25,771
    Joined:
    Apr 19, 2005
    Location:
    Rochester, NY
    Shooter:
    Multi Format
    The correct filters for narrow cut are 98, 99 and 70. For a broad cut, I would have to look it up.

    PE
     
  9. wildbillbugman

    wildbillbugman Member

    Messages:
    819
    Joined:
    Apr 18, 2005
    Location:
    San Bernardi
    Shooter:
    8x10 Format
    Thanks Eveyone!
    On the Yahoo Group "Dye Transfer" a couple of people thought that TMY and TMX were not suitable for color separations. In fact, I have been doing color seps for years.
    But I use the separation negatives for Alternative Processes, specificly Pt/Pd and pigment/dichromate printing. Both of these require U.V. exposure. I have started asking questions because TMX is said to now have a u.v. blocker,which Decreases effectve speed by 3 stops as far as U.V. is concerned.
    I need to find a film which is close to T-MAX 100, but which has no U.V. Blocker.
    Bill
     
  10. tiberiustibz

    tiberiustibz Member

    Messages:
    1,749
    Joined:
    Oct 22, 2007
    Location:
    Tufts Univer
    Shooter:
    35mm
    I heard something about Kodak making runs of TMAX without UV blocking.
     
  11. sanking

    sanking Member

    Messages:
    4,813
    Joined:
    Mar 26, 2003
    Location:
    Greenville,
    Shooter:
    Large Format

    Then use TMY. It has a long straight line curve very similar to that of Tmax-100, with almost identical spectral response, plus it is two stops faster which will help a lot to compensate for the additional exposure you will have to give because of the filters.

    Sandy King