Adjusting contrast for digital projectors

Discussion in 'Digital SLR' started by Paul Furman, Feb 2, 2006.

  1. Paul Furman

    Paul Furman Guest

    I'm preparing some photos for a slide show on a digital projector and I
    know those awful things boost contrast so I'm thinking of reducing
    contrast on the images.

    My projector bulb is burned out at the moment though so I can't test.
    Maybe someone can test this or already knows the appropriate adjustment.
    I think it's more a matter of blocking up shadows than blowing
    highlights (though I'm not sure) so maybe with a photoshop levels
    adjustment on the lower 'output' slider to cut off to 50-255 (starting
    at 0-255).

    Or will this even work? It's a shame to see the photos butchered on
    those projectors!
    Paul Furman, Feb 2, 2006
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  2. Paul Furman

    Mike Russell Guest

    Have you tried running Adobe Gamma using the projected image as a reference?
    If this is not available, the display driver may have a gamma adjustment.
    The location of the display control panel depends on whether you are using a
    Mac or PC.
    Mike Russell, Feb 2, 2006
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  3. Paul Furman

    C J Southern Guest

    I don't use a projector, so I can't help with your original question, but
    you may or may not know that the Spyder2Pro Studio kit comes with all the
    necessary evils to profile your projector so you wouldn't have any of these
    issues in the future.
    C J Southern, Feb 2, 2006
  4. Paul Furman

    J. A. Mc. Guest

    If you have a friend with a laptop and an LCD screen you can approximater
    the butchery.

    FWIW, I'd go with a gamma or curve adjustment, not contrast!

    IF you've got a good projector, it too will have a gamma option - perhaps
    you can get the setup tech to use it. Furnish a 16 step greyscale as a
    J. A. Mc., Feb 2, 2006
  5. Paul Furman

    Paul Furman Guest

    My friend is going to show them on his projector, I know it boosts
    contrast similar to mine and I don't think there is any adjustment. I'll
    probably not be able get him to set it up for tests in the evening.

    Hmmm, gamma is more like the brightness of middle tones and I think the
    issue is really contrast. Middle tones are probably about correct but
    colors get oversaturated & shadows blocked up.
    Paul Furman, Feb 2, 2006
  6. Paul Furman

    Paul Furman Guest

    The projector to be used is a mac, mine is a pc. Is this something that
    can be adjusted on the computer? I doubt his has adjustment in the
    projector, mine doesn't & his is smaller. I think they make them high
    contrast so it works in a partly lit room like for business meetings.
    Paul Furman, Feb 2, 2006
  7. Paul Furman

    Mike Russell Guest

    I'd recommend that you install Adobe Gamma on the Mac, if you have access to
    the Mac version. Run it in wizard mode, and try to adjust it according to
    the instructions. If you can get things looking good - and there are no
    guarantees - you're set. Another possibility is to use the display control
    panel - some drivers have adjustments for gamma and/or brightness and

    Another trick I've heard of - from Andrew Rodney - is using the Eye One
    Color. It's designed to be used with a CRT or an LCD, but if you point it
    backwards, it can be fooled into calibrating a projector. Cool, huh?

    If you post the model number of the projector, someone may post with more
    direct experience.
    Mike Russell, Feb 2, 2006
  8. Paul Furman

    John Forest Guest

    Our camera club just purchased a digital projector. We ran Adobe Gamma and
    the pictures still looked too contrasty. We ran it again, this time
    ignoring the first step prescribed by the wizard, to set the monitor to the
    maximum contrast. We put the contrast (using the projector controls) back
    to the default value. (It allows plus or minus settings up to 14.) We then
    did the rest of the setup as called for in Adobe Gamma, with the box
    unchecked for "view single gamma only" We found it helpful to defocus the
    projector slightly when doing the setups for red, green and blue. With the
    setup this way the pictures were a very close match to what was seen on the
    monitor. Another thing we found was that the projectors have a very short
    projector to screen distance and it is tempting to angle it upward and use
    the keystoning control to make the picture rectangular. That results in the
    bottom of the screen being much lighter than the top. We took steps to
    raise the projector so it is parallel to the screen to solve this problem.
    John Forest, Feb 2, 2006
  9. Paul Furman

    J. A. Mc. Guest

    Video Gamma is a bit different than photoshop's 'gamma'. It's used to
    stretch the black areas and lightly compress the upper highlights.

    Don't forget too, that photographic imagery goes to "0" black. Video cameras
    never go below "20". Also Video camera "white' is really more like "224".
    The video space allows higher levels, but they are for reflections and often
    are clipped. LCDs exacerbate the clipping 'look'.
    J. A. Mc., Feb 2, 2006
  10. Paul Furman

    J. A. Mc. Guest

    Better projectors have allowed for this with a lens shift mechanism, similar
    to Perspective Control lenses or a swing lens in a portrait camera.

    Projection and Video 'space' is different from monitor space as far as
    levels go.
    J. A. Mc., Feb 2, 2006
  11. Paul Furman

    Paul Furman Guest

    My projector is a Dell 2300MP. Holy shit, the replacement bulb is $350!
    Anyways it defaults to keystone correction assuming it's pointing up
    from a conference table and that's adjustable in the menu but any
    adjustment in the menu seems to put it into instability causing the
    image to drift to the side & requiring 'reset-all' to fix. When I get
    another bulb I'll see if it's possible to adjust contrast for profiling.,1759,1710890,00.asp
    Paul Furman, Feb 2, 2006
  12. Paul Furman

    J. A. Mc. Guest

    Sorry, I don't have the tech setup papers for any Dell machines.
    If it 'defaults' to keystone correcting, then there's no lens shift.

    That price on the bulb is 'cheap' - the ones we use are $800 to $1500! <G>
    When you consider that slide projector bulbs last about 30 hours and run
    $20, you should be paying double that for your 1,000 hours. <G>
    J. A. Mc., Feb 3, 2006
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