calibration image files

Discussion in 'Digital Photography' started by Michael Sierchio, May 22, 2006.

  1. I've been finding that the use of proof viewing in PS doesn't
    completely cut the mustard, even with a calibrated monitor
    and supposedly accurate printer profile.

    So, I've been devising images intended to do the following:

    find the highest RGB grayscale level distinguishable from White

    find the lowest RGB grayscale level distinguishable from Black

    reveal local contrast limits throughout the range (i.e. can
    we distinguish a 1-luminance difference here? 2?)

    map the convex hull of the printer/paper color gamut
    with as few samples as possible.

    In the coming weeks I'll be posting some images to a website,
    and am also interested in knowing whether anyone has such
    images which they find useful, whether hand-crafted or
    as supplied by color calibration tools.

    Cheers.

    - Michael
     
    Michael Sierchio, May 22, 2006
    #1
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  2. Michael Sierchio

    Joe Petolino Guest

    Michael Sierchio wrote:
    > So, I've been devising images intended to do the following:
    >
    > find the highest RGB grayscale level distinguishable from White
    >
    > find the lowest RGB grayscale level distinguishable from Black


    I posted an image of mine here last February for the above two tasks:

    http://www.pbase.com/petolino/image/55994572

    There are instructions on the page.

    -Joe
     
    Joe Petolino, May 23, 2006
    #2
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  3. Michael Sierchio

    bmoag Guest

    I guess I don't get it.
    There are many programs out there that do the same thing, try to determine
    one's ability to discriminate tonal gradations, in one form or another. In
    fact this is the basis of the Adobe Gamma Applet. This is a not very
    reliable way to tune one's color managed workflow.
    Personally I think you fail to understand the point and application of
    calibration.
    You might want to look into the several devices on the market for creating
    personal printer/paper profiles. This is a much more practical way of
    achieving individually tuned calibration so that a reliably predictable
    result will be achieved with particular printer/ink/paper combinations.
    It is measurable and reproducible. There is no straining of one's aging and
    imperfect eyes staring at monitors that are as flawed imperfect image
    reproduction devices as one's eyeballs.
    Such calibration is always an ongoing effort, not a one time shot.
     
    bmoag, May 23, 2006
    #3
  4. Michael Sierchio

    D Mac Guest

    bmoag wrote:
    >> I guess I don't get it.
    >> There are many programs out there that do the same thing, try to
    >> determine one's ability to discriminate tonal gradations, in one
    >> form or another. In fact this is the basis of the Adobe Gamma
    >> Applet. This is a not very reliable way to tune one's color managed
    >> workflow.
    >> Personally I think you fail to understand the point and application
    >> of calibration.
    >> You might want to look into the several devices on the market for
    >> creating personal printer/paper profiles. This is a much more
    >> practical way of achieving individually tuned calibration so that a
    >> reliably predictable result will be achieved with particular
    >> printer/ink/paper combinations.
    >> It is measurable and reproducible. There is no straining of one's
    >> aging and imperfect eyes staring at monitors that are as flawed
    >> imperfect image reproduction devices as one's eyeballs.
    >> Such calibration is always an ongoing effort, not a one time shot.


    ----------------------
    That's an intelligent alternative to discover the tonal range of your
    printer - NOT!
    Shooting from the hip carries the likelyhood of sticking it in the wrong
    place.
     
    D Mac, May 23, 2006
    #4
  5. Joe Petolino wrote:

    > http://www.pbase.com/petolino/image/55994572


    This does half of what I want for grayscale. The other half
    is seeing what the threshold is for detecting a difference
    between two values across the range of paper densities (i.e.
    can we detect a difference of 1RGB at r=100,g=100,b=100?).

    I have some images which do this, which I'll post when I
    get the webserver back up. ;-)
     
    Michael Sierchio, May 24, 2006
    #5
  6. bmoag wrote:
    > I guess I don't get it.


    You guess right.

    ICC profiles are a good first step, but guess what? Printers typically
    discard profiles and print what the RGB values say. The purpose of
    the profiles is to give some previsualization help in whatever medium
    you're using to view the digital negative (e.g. Photoslop).

    I'm a demanding user, and press the limits of the print medium all
    the time. Losing local contrast because the proof settings on the
    screen don't tell the whole picture is not acceptable.
     
    Michael Sierchio, May 24, 2006
    #6
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