Canon Rebel XTI/400d, PhotoShop RAW and gretagmacbeth

Discussion in 'Canon' started by John, Dec 15, 2006.

  1. John

    John Guest

    I don't know which forum to post on so I thought I'd start here.

    I'm trying to calibrate my Camera Raw color settings. I know I don't have a
    good eye for color so I bought a gretagmacbeth colorchecker chart.

    I have a Canon Rebel XTi/400D with Photoshop Camera Raw 3.6.

    I have ACR-Calibrator.js which supports Photoshop CS2 and ACR 3.4. I haven't
    found a version that supports ACR 3.6.

    I run the ACR-Calibrator.js script in Photoshop which seems to do a whole
    bunch of processing then ends with an error message "Your installed version
    of Adobe Camera Raw (ACR) is not supported by ACR Calibrator"

    After having beat myself up for most of the day trying to find an alternate
    way, I've thrown in the towel. My Photoshop CS2 RAW book by Mikkel Aaland
    states in an earlier chapter that color correction will be covered in chapter
    10 but it's not. But he does mention gretagmacbeth charts.

    Anyway, here's my question: Since I already have the RGB color values for
    each of the 24 colors from gretagmacbeth, is there some way I can just punch
    the values in somewhere?
    John, Dec 15, 2006
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  2. John

    bmoag Guest

    I may be missing something:
    I do not understand what following this procedure will get you rather than
    monitor calibration, color management and, if you can afford it,
    calibrations of your particular printer/paper combinations.
    Hardware monitor caibration and color managed image processing and printing
    is very accurate for most purposes if properly done.
    Any photo of a color chart for calibration purposes is only valid to the
    particular lighting circumstances under which the image was created.
    bmoag, Dec 15, 2006
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  3. John

    w.beckley Guest

    The purpose of doing this is to ensure that the workflow is calibrated
    from camera to digital file, basically the first step of the process.
    While it is true that calibrating is *really* only good for the
    lighting setup under which the image was made, a calibration using
    color-balanced lights (measured with a calibrated color temp meter)
    will give you a better starting point for your camera than the built-in
    profile. How much better? Not too much, but noticable in my experience.
    Most cameras have slight color shifts of their own, and if you've
    reason to be anal, you can eliminate them.

    Depending on the workflow, this step, along with monitor calibration,
    is enough to have a color managed workflow for digital-only images.
    Profiling your printer is the next step if you want to go to print.

    Obviously, a calibrated monitor is most important, because at least
    then you can be confident that what you're seeing is what you've got.
    But in some cases it might be important to know that what you saw when
    shooting is where you'll start from in post. Shooting ads for
    Coca-Cola, for example, where much money is spent ensuring the fidelity
    of the red used, would be a time to profile your camera.

    True story: Coca-Cola's ad people (for commercials) will come into a
    color correction suite with a machine-cut stencil to place over their
    own vectorscope (used in the video world to track chroma values).
    There's a small hole where "Coca-Cola red" should fall, and they always
    check to make certain that it does.

    As for the original poster's question: I don't think I can ethically
    give you this information, but you can find a good, easy-to-follow
    workflow in Bruce Fraser's "Real World Camera RAW with Adobe Photoshop
    CS2" from Peachpit Press. And it is a great reference as well.

    w.beckley, Dec 15, 2006
  4. John

    John Guest

    Yes, I think you might be missing something.

    I want to calibrate my ACR. According to the procedure for ACR-Calibrate one
    takes a photograph of the color card. Then using the photograph of the color
    card, a profile is built for that camera. If there was a version
    ACR-Calibrate that handled ACR 3.6 (I need 3.6 since I have a Canon 400D) I
    woulnd't need to be asking this question to begin with.

    Afterwards, a color card is included at least once during every photo shoot
    since the lighting will always be different.

    One person on the Internet said that he bit the bullet and entered the colors
    by hand into Photoshop but I haven't figured out how to manually enter color.

    For example, white is 243,243,242. Black is 52,52,52 and green is 70,178,149.
    Where do I enter those colors?
    John, Dec 15, 2006
  5. John

    John Guest

    No problem. I'll go down to the bookstore and get the info for free. At
    least now I now know where to look.
    John, Dec 15, 2006
  6. John

    Paul Furman Guest

    On CS2's 'Calibrate' tab... although it's not a simple RGB scheme so I'm
    not sure how.

    Adjust | Detail | Lens | Curve | Calibrate
    Paul Furman, Dec 15, 2006
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