RGB Tricolor filters for separation photography

Discussion in 'Accessories' started by matt_t_butler, Jul 13, 2018.

  1. Everything about the availability of RGB camera filters that you were afraid to ask …..

    Wratten (original Eastman Kodak)
    Tricolour photography suggested set for ‘one-shot tricolour cameras’ with B&W negatives
    #25 Red; #58 Green; #47 Blue - Early nomenclature ‘A’ (Red); ‘B2’ (Green); ‘C5’ (Blue)
    Tricolour set for direct separation (‘in camera’) B&W photography
    #25 Red; #61 Green; #47 Blue;
    Tricolour set for colour separation copy from colour transparencies
    #29 Red; #61 Green; #47B Blue
    These were the Kodak standards but photographers devised their own sets depending on film types and Daylight or Tungsten lighting set ups.

    Harris Shutter 1971 (Kodak AE-90)
    Mounted gelatin filters in a drop shutter #25 (Red); #61 (Green); #38A (Blue)

    Wratten 2 (contemporary Kodak)
    #25, #26, #29 Red; #58, #61, #99 Green; #47, #98 Blue
    #99 (#61+#16 Yellow/Orange); #98 (#47B+#2B Pale Yellow)
    Loading site please wait...


    Glass filters
    #25, #29 Red; #58, #61 Green; #47, #47B Blue

    Lee Filters for 100mm system
    Polyester Tricolour Red #25; Green #58; Blue #47B (0.1mm thickness)
    The tricolor polyester filters have been designed for tricolor photography and work well for that purpose.
    Dichroic filters (or any filters designed to go over lights) are not optically pure and would compromise sharpness when used over a camera lens.

    The SP Color Set contains Red, Green, Blue filters for ‘factorization photography’ - similar to
    a set by Prisma released in the 1970s.
    SP Color Set- Kenko Global Site

    Cokin P Filter kit has a Red P003, Green P004 not suitable for tricolour work. (Needs clarification)

    Formatt HiTech
    Various filters in #25 Red; #61 Green; #47 Blue
    Not listed on their website ? but available special order through B&H Photo NYC
    Formatt Hitech 67mm 47 Dark Blue Camera Filter HT67BW47 B&H


    R60 (Red #25); X1 (Green #11); B12 (Blue #80B)
    The X1 and B12 are unsuitable for true tricolour work


    090M is equivalent to #25 Red; 091M is a #29;
    061 is #13 Green (No longer available?); 081 is a medium Blue (No longer available?)
    All are listed in their handbook but the 061 and the 081 are unsuitable for tricolour work

    Moderator Note:
    Please see Post #37 by OP containing revised information.
    Last edited by a moderator: Sep 19, 2019
  2. Vincent Peri

    Vincent Peri Metairie, LA

    Hmm... there go all my
    dreams up in smoke...
    matt_t_butler likes this.
  3. Maybe not quite everything.

    For still life/studio work you can use gels over flash or hot lights for separation. In which case the Lee theatrical 'gels' are quite suitable. And in the absence of anything else, I recently used a piece of Lee dark blue gel over a camera lens with very little detriment to the image quality. Just don't get your fingerprints all over the gel!

    Actually, I'm pretty sure that the manufacturing technique for theatre lighting polyesters has improved greatly of late, and that it can be used as a make-shift camera filter reasonably safely. Just eyeball it for obvious blemishes before use.
    matt_t_butler likes this.
  4. Dustin McAmera

    Dustin McAmera Yorkshire, mostly on film.

    Who needs red, green or blue when you have Orang?
    Vincent Peri likes this.
  5. I'm still confused. - I'd be interested in an ability to create color work in a pinch and have a Kodak sensored Monochrom and some film stuff. Do I want the
    ? - And how am I supposed to generate my K-film for printing?
    matt_t_butler likes this.
  6. If only, and duly noted ... probably should of said 'using this set on the camera for photography rather for copy/rostrum work'.
  7. 'Everything about the availability of RGB camera filters that you were afraid to ask ….. '

    And yes - you can use some theatrical gels but they are generally not dyed to match the spectral response of their comparison lens filters and do not match the optical quality of glass.
    Great for experimentation - I once even used 'prime' Red, Blue and Green acrylic plastic (Plexiglass, Perspex) cut to 4" x 5.6" when I could not afford the glass filters. Gave an acceptable result.
    Last edited: Jul 14, 2018
  8. "...they are generally not dyed to match the spectral response of their comparison lens filters."

    - That may not matter terribly much. There seems to be no specification for the exact film spectral response to match a given set of separation filters, nor a specific illumination CT. And since B&W negative film is the target 'sensor', then processing will play a large part in the transfer function of the end image.

    I suspect that anyone doing colour-seps these days will be combining and re-colouring them after scanning and in an image editor. In which case there's immense flexibility in the complementary CMY 'dyes' that can be applied.

    It's not like you'd have to carefully match 3 or 4 colour positives to a specific set of SWOP colours.

    In short, I'm pretty sure that with current technology any old reasonably dense RGB filters could be made to render acceptably faithful colour in the re-combined image.
  9. 'In short, I'm pretty sure that with current technology any old reasonably dense RGB filters could be made to render acceptably faithful colour in the re-combined image.'

    Absolutely correct!
    Makes one appreciate the craftsmanship (craftspersonship?) applied to dye transfer and multi-colour print reproduction processes in the days before computers.
    As colour is fairly subjective and photograhic post-production applications are all encompassing, then modern RGB compositing is a matter of personal expression.
  10. Sorry, Matt I don't get your sentence there. And also sorry, if I sound(ed) confusing. Yes, I am a press man by trade and for that reason somewhat interested in reproduction technology. That's why I'd seriously love to understand how K-films get (or got?) generated reprographically and outside the digital darkroom.
    I don't get the difference between photography and copy work, as far as separation is concerned. Doing single camera triple shot color seems quite limited to really static subjects if perfection is the goal? The alternative would be artsy fun.
    Even if I'll end dabbling with multi Monochrom shot color, I'd love to avoid
    and rather have something I could send almost straight to the laser printer at work.
  11. Back in the day Kodak suggested using two different filter sets - one for photography and the other for separation work.
    The camera filters were 'broadband' spectrum filters used in early 'one shot tricolor cameras' while the separation set were 'narrow cut' filters used to produce RGB copy B&W negs from Kodachrome and Ektachrome transparencies.
    Last edited: Jul 14, 2018
  12. RGB on Kodachrome 35mm film

    matt_t_butler and Jochen like this.
  13. "..and rather have something I could send almost straight to the laser printer at work."

    - How?
    To the best of my knowledge, there's no laser printer that can take 3 B&W negatives or positives as the input files for colour output.

    There's never been a bullet-proof separation process. All of them have to be tailored to the final CMY(K) dyes used, or printing paper, film or whatever medium; either by trial and error, or careful densitometer readings, or dot measurement and dot-gain compensation.

    Not only that, but electronic scanning of transparencies has been used since at least the 1970s in the printing industry. And before that there were 'one shot' separation cameras using beam-splitter prisms and built-in filters, for both still and cine cameras.
  14. It was never really "easy"
    kit from October, 1939 Popular Photography
    matt_t_butler likes this.
  15. Erratum for moderator
    In the original opening post there is a line: 'Tricolour set for direct separation (‘in camera’) B&W photography'
    Should read : Tricolour set for direct separations from original B&W photography.

    The words 'in camera' - as pointed out suggests the process can be done entirely in camera.
  16. From earlier post: 'Cokin P Filter kit has a Red P003 (Wratten #25).
    Green P004 not suitable for tricolour work. (Needs clarification)'

    Cokin P 004 clarification.jpg
    Last edited: Aug 4, 2018
  17. Some lenses-esp. UWs-have a gel clip at the rear since a front screw-on is impractical. Of current production lenses, the AF-Nikkor 14mm f/2.8D has this. Many super-teles either come with or have available as an accessory a gel holder for the filter drawer(although that's less less relevant since at least on Nikon lenses you can fit a Nikon brand screw in filter of the proper diameter).

    What sort of gel would you suggest in those situations where glass is not possible?
  18. Kodak still market their optically clear filters branded Wratten 2.
    I don't know how thin these 'new' filters are but one can buy second-hand and generally unused original gelatin Wrattens on Ebay for reasonable prices.
    If anyone on the forums knows the thickness of Wratten 2 filters please let me know.

    Try Googling ' WRATTEN 2 FILTERS' for photographic outlets that stock them - they are used by cinematographers as well.

    Kodak link : Loading site please wait...
    Last edited: Aug 9, 2018
  19. Messing about with tricolour filters.

    Dumbo photographers NYC.png
    Dumbo photographers and tourists.
    Canon 5D2, FD 50mm/f1.8, (Effective 63mm/f2.4 with FD to EOS 1.25x adapter) @ f11, 1/30sec, ISO 320, triple exposures using Wratten #25 Red; #58 Green; #47 Blue.
    Composite frame grab from FCP X.
    Supriyo and Vincent Peri like this.
  20. As three separate files, it would take some tricks, but concatenated appropriately with the right Postscript code, I think it could be done.

    The Postscript colorimage operator has enough options that it is hard to say what could be done with it.

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