ICM = ICC? (color calibration trouble w/ Adobe Gamma)

Discussion in 'Photoshop Tutorials' started by Matthew.DelVecchio, Jul 20, 2005.

  1. hello all,

    i recently bought a Hynundai L90D+ digital LCD panel, which i have
    plugged in to my geforce4 via a DVI cable. after reading a text on
    color management, i thought i would do some poor-man's calibration, via
    Adobe's Gamma tool. (id rather hold off on buying monitor calibration
    hardware/software until after i see results from the AG tool, which is
    better than doing nothing at all). i am running windows xp.

    trying to use Adobe Gamma to calibrate the monitor. from the book ive
    read, the first step is to begin by loading the monitor's provided ICC
    profile as a starting point, and tweak it from there using the utility.
    Hyundai provides this file:

    L90DPD.ICM
    (L90DPA.ICM too, which i assume is for the analog cable use)

    ....however when i load it, AG kicks me this message:

    "The selected profile is not a legal RGB display profile"

    i am sure this is related to another error i get when i load CS2 and
    have the same profile set as my default (via windows):

    The monitor profile "Colorific: PnP VESA DDC - HYUNDAI ImageQuest L90D
    Digital" appears to be defective. Please rerun your monitor calibration
    software.

    any idea whats up? is it because this is a ".ICM" and not a ".ICC"
    file? are they the same things?


    thanks!
    matt
     
    Matthew.DelVecchio, Jul 20, 2005
    #1
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  2. Matthew.DelVecchio

    Matti Vuori Guest

    wrote in
    Both file suffixes are used and they don't matter (if you are in doubt,
    just change the suffix). Perhaps the profile file is indeed defective.
    Check if the manufacturer has a profile for download in its web site.
     
    Matti Vuori, Jul 20, 2005
    #2
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  3. i didnt see an updated one posted, but i will continue to inquire.


    thanks
    matt
     
    Matthew.DelVecchio, Jul 21, 2005
    #3
  4. Matthew.DelVecchio

    Bill Hilton Guest

    wrote
    Why bother? The manufacturer's monitor profiles are irrelevant and
    inaccurate once you make a single change of the brightness, contrast or
    color controls, or as soon as you've made a single pass with a
    profiling system like Adobe Gamma. It's not worth the bother to even
    download a monitor profile from the manufacturer, you *have* to make
    one yourself for your monitor to get an accurate profile.

    Bill
     
    Bill Hilton, Jul 21, 2005
    #4
  5. i see. didnt realize that.

    as a new lcd user, i figured i would want to get it all synched up as
    possible, like when i install new vid card drivers.

    if not, well, what's the point of monitor profiles?


    matt
     
    Matthew.DelVecchio, Jul 21, 2005
    #5
  6. Matthew.DelVecchio

    Bill Hilton Guest

    wrote
    What a good profile will do is accurately display the colors
    represented in the image file on YOUR screen, when you use a color
    managed application. But the profile is tightly bound to one screen
    and that's why a generic monitor profile isn't much use, just as a base
    starting point (if you have one handy) before you actually run the
    first real calibration/characterization.

    Think of it this way ... when you run the software you'll choose a
    gamma setting and a white point and you'll fiddle with the brightness
    and contrast and color settings to get to a known good point -- this
    step is called 'calibration' and as soon as you change any of these
    parameters you'll need to do it again. Now, did the factory-provided
    profile use your laptop screen when it generated the profile? No. Are
    *all* of your settings (gamma, white point, brightness, contrast, color
    settings) identical to what the factory used on their monitor? Not
    very likely. Then add in differences between units and realize that
    monitors shift over time (most calibration companies recommend
    re-running the software every two weeks) and you can see that there's
    little likelihood that a generic profile from the manufacturer is very
    accurate.

    So you need to generate a profile for your own specific machine under
    your typical viewing conditions with your settings for gamma, white
    point etc and then do not touch those dials or you'll need to repeat
    the process.

    Bill
     
    Bill Hilton, Jul 21, 2005
    #6
  7. Matthew.DelVecchio

    Mike Russell Guest

    Bill and I have long ago agreed to disagree on this one, so here goes.

    A calibration device is not necessary or even desirable for a single user
    system. It is possible to get your monitor very close to accurate using
    Adobe Gamma. Careful use of Adobe Gamma, or a similar utility, is
    sufficient for good color. Using the manufacturer's profile as a base will
    provide a measure of accuracy by ensuring that the monitor primaries match
    the monitor's phosphors.

    There is no need to feel that your setup is inadequate in any way if you do
    not use a colorimeter.
     
    Mike Russell, Jul 22, 2005
    #7
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