Color correction filers??

Discussion in 'Color: Film, Paper, and Chemistry' started by stradibarrius, Jan 21, 2010.

  1. stradibarrius

    stradibarrius Member

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    I need some help trying to decide how to correct color using filters.
    I have attached two photos of a violin which are typical results when I use film rather than my digital.
    Set up: RB67 w/90mm, Kodak 400VC color neg. film.
    Lighting is two photo spots w/ 250w 3200deg. bulbs.
    Background is a black cloth.

    The violin, in person, is about the color on an amber beer.

    The shots have NO post processing. They were scanned and size for this forum.

    What would you use to correct the color? I can do it in Photoshop but I want to try to learn to get it right in the camera...damnit!!!
    I can get it right with my digital camera as well but I want to use my film cameras.

    Can you help?
     

    Attached Files:

  2. jeffreyg

    jeffreyg Subscriber

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    Tungsten film: Fuji RTP 64 or Kodak EPY 64T
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    I would take out a 5 yellow for the one on the left and add a 10 yellow or 15 yellow to the one on the right. You will need to adjust the exposure for the one on the right by about 10 - 20%.

    Just a guess.

    PE
     
  4. tiberiustibz

    tiberiustibz Member

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    You need an 80A color correction filter over the camera lens. It's nearly impossible to correct after shooting, your blacks will always be blue and/or your highlights yellow. Some shifty photoshop work can correct some of this, though it never looks good. Using a tungsten film like the deceased portra 100t or Fuji 64T is optimal. I have a brick of the fuji slide film if you want to buy it. I bought it when the film was "discontinued" a year ago, though it still seems to be everywhere...
     
  5. fotch

    fotch Member

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    "What would you use to correct the color?"

    Strobes. I got all the on the lens filters, however, found it easier to use studio strobes. Less heat and no bugs cooking themselves on the hot lights during the warmer weather. Strobes are easier on people subjects also. The only thing I wish I had would be a spotlight strobe, which are beyond my budget.
     
  6. Lee L

    Lee L Member

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    Read up on color temperature and mired (micro reciprocal degree) adjustments. This will help you understand what you're trying to do, and to learn how to calculate adjustment customized to fit your needs.

    You need to either convert the color temperature of the light falling on the subject by putting gel filters on the photofloods, or to filter at the camera lens to adjust the light getting to the film.

    For the photofloods, you could go to a CTB filter, which is a blue color temperature adjustment filter. A full CTB converts a 3200K tungsten light source to about 5500-5700K for daylight film. There are also 3/4, 1/2, 1/4 and 1/8 CTB filters available for less agressive adjustments. (CTO filters, in orange, or CTS filters, in straw colors, convert in the other direction.) These gel filters are heat resistant and available for under $7 in 20x24 inch sheets, the most common brands being Lee and Rosco. The web sites for Lee and Rosco will have information on how to use the CTB/CTO/CTS filters, and all the major suppliers will normally have these common filters in stock. This is likely the most efficient, adjustable, and inexpensive route to take outside of using software that you already own.

    For your camera lens, the suggested 80B would be the correct filter for shooting daylight film under 3200K tungsten lights. An 80A would be slightly less correction, and you might find that preferable because it won't turn the wood as cold looking.

    Only adjust the light source, or at the camera lens, not both, unless using partial correction for each, totaling to the correct overall adjustment.

    As you can see, your scanning software or image editing software is trying to do its own color correction, which is the reason your posted image colors don't match. That's a separate issue in the digital domain, which we don't really talk about here. However, a color standard target in a test shot will allow you to correct on a frame with the color standard in it, then save and apply those corrections to another frame without the standard included. Good standards would be something like a MacBeth Color Checker (now X-rite), an X-rite Passport color checker (http://www.xrite.com/home.aspx), something like a Kodak Q-13 step wedge and color target, or a card with good clean white, gray, and black patches on it, such as one of the WhiBal products (or a home brew equivalent) or some of the Photoflex or Westcott flexible targets.

    Software can correct color temperature across the range of densities, despite what others might tell you. It just needs to be done properly, and black/gray/white patches in a test target will help with that. I highly recommend the X-rite Passport Color Checker, as it can be used for traditional printing, digital editing, and has patches for a slight warming effect in one of the rows, which can be used to lend a bit of warmth to things like skin and your instruments. Several image editing programs will also allow you to place a grid over the X-rite Color Checkers (all versions) and produce a more comprehensive and accurate color adjustment profile. The Passport version includes software for this adjustment.

    Lee
     
  7. Lee L

    Lee L Member

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    I should also have mentioned that Lee sells a version of the full CTB gel with diffusion built in, for a softer light and color conversion in the same filter.

    Lee
     
  8. DanielStone

    DanielStone Member

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    Personally, I've found that shooting the Portra VC line of films under hot lights WITH an 80a filter(on lens) or by gelling your lights with a FULL CTB(3200k-->5500k), you are still somewhat on the warmer side of things.

    If you want the BEST color accuracy, I'd try using the 160NC or 400NC films, because of their NATURAL COLOR(NC) balance.

    VC is great in sunlight(for me), and with strobes, but for hot lights, I'd use NC converted, less color casts, even when done "right"

    just my $.02

    also, try shooting a color checker card/grey card on a frame in the roll, so you can easily zero-in your color with a simple click in post(sc@NN1Ng)

    -Dan
     
  9. Photo Engineer

    Photo Engineer Subscriber

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    The OP asks how to correct the images he has. My advice stands for those images. However, as everyone else has pointed out, and correctly, the film is daylight balanced and was shot with tungsten illumination.

    This is, when you get down to it, uncorrectable. See the excellent illustration of this in the book by Ctein, "Post Exposure".

    PE
     
  10. Lee L

    Lee L Member

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    I took the OP's statement "I can do it in Photoshop but I want to try to learn to get it right in the camera" to mean that he wants to correct future shots of the same kind of subject with filtration during the film exposure, not at reproduction of the negatives from which he's posted scans.

    As PE stated, Ctein shows that it's not possible to correct properly during optical printing after shooting under the wrong combination of film and light source color balances, as shown in figure 2-10 on page 22 of "Post Exposure", where there is color crossover because of the offsets of the curves of the individual color layers in the film under the wrong illumination.

    Ctein also says (page 21 last column) that excellent results can be had by filtering at the light source or at the camera with the proper color conversion filters, even to the point that if you admire the tone and color characteristics of one film sufficiently, it may well be worth using it under the non-matching light source with the proper correction filtration. He's picky enough about color that I count this as a ringing endorsement of this method, which I encourage the OP to try.

    Lee
     
  11. jeffreyg

    jeffreyg Subscriber

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    Another issue that you did not mention is do you want detail in the background cloth? If not you have too much illumination of the background whic should be further away from the subject. Also will you be scanning the negatives and printing digitally? If so there are the scanner, scanner software, monitor, printer and paper that any or all can make a difference.
     
  12. stradibarrius

    stradibarrius Member

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    I meant to say how to correct this type of shot in the future, not to correct these photos.
     
  13. Photo Engineer

    Photo Engineer Subscriber

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    Thanks for the correction about correction. :wink:

    The advice then is to use the right lighting for the film just as most everyone has advised.

    PE