Westcott Digital Calibration Target

Discussion in 'Digital Cameras' started by Mooda, Feb 27, 2005.

  1. Mooda

    Mooda Guest

    Can anyone tell me how to use the Westcott Digital Calibration Target to set
    white balance? I got one, but without instructions. On the Westcott
    website there's a page for instructions but all the links are broken.

    The target is advertised as providing exposure calibration, but I've heard
    that it can also be used to set white balance for high key shotos. Can
    anyone share information about that?
     
    Mooda, Feb 27, 2005
    #1
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  2. Mooda

    Crownfield Guest

    what is white balance, and how do we get it?

    it is color balancing a camera, or image
    so that the white in the subject is white in the image.

    we point the camera at a gray or white object,
    and set color balance.

    ow we just set the proper balance in the camera, like daylight,
    and then use our photo software to correct the resulting image
    to perfection, using a gray or white part of the picture.
    white shirts or cloudy skies work perfectly.
     
    Crownfield, Feb 27, 2005
    #2
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  3. Mooda

    Mooda Guest

    Thanks, but I'm looking for information about using a Westcott Digital
    Calibration Target to set correct white balance when shooting a high key
    set.



    The procedure you describe above is for color correction after you've shot a
    scene using incorrect white balance. While that procedure can remove minor
    unintended color tinges, it doesn't really restore white balance. For
    example if you shoot a blue blouse on a white background using a digital
    camera with an incorrect color temperature setting, the white background
    won't come out looking quite white. If you then "correct" the white
    background using the Curves tool in Photoshop, you unfortunately also change
    the color of the blue blouse. If someone then buys a blouse based upon your
    picture they will be disappointed to discover that the product color doesn't
    match the pictured color.



    A high key set is one in which the white background is deliberately
    over-exposed to the extent that it becomes indiscernible in the photo. The
    subject is lit separately, and correctly exposed. When shooting a high key
    set with a digital camera, if you don't set the exposure and white balance
    correctly, bands of grayish-blue or pinkish-red color appear in the digital
    image. Correcting those bands without altering the exposure or white
    balance of the subject can be difficult, often requiring matt work.



    I've heard from several sources that the Westcott Digital Calibration Target
    is very helpful in setting the correct exposure and color balance. But
    there's some trick to it; it's not done in quite the same way as setting
    white balance off an 18% gray card, from what I've heard.



    Can someone who has used the Westcott Digital Calibration Target for high
    key photography please explain the technique? Thank you in advance.
     
    Mooda, Feb 27, 2005
    #3
  4. Mooda

    Crownfield Guest

    the white balance, custom set in the camera should still hold, right?

    then the only question is how much to lighten the background.
    some experimentation, looking for 255's in the white,
    should get you very close. I suspect those banding problems
    will happen only in overexposure overloading the sensor.

    I did search in both google and google groups, and found no joy.
    searching for 'high key set' got more useful information.
    http://www.tallyns.com/Photo_Tech_Tips/techtips.htm


    also, have you considered a chroma key blue / green background?

    shoot a relatively normal shot, strip the background in processing,
    and then, with the digital sensor out of the way,
    juggle the forground any way you want? lighting should be easy,
    and the editor should show no band problems.

    any changes in the forground will have no effect on the background.
     
    Crownfield, Feb 28, 2005
    #4
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