Monitor calibration and color managed workflow question

Discussion in 'Digital Photography' started by Stanislav Meduna, Dec 19, 2005.

  1. Hi,

    I bought a Colorvision Spyder and calibrated my monitor.
    It really helped. However, I am not really sure how this
    works and I fear I might be double-color-managing.

    The Spyder generates an ICC profile, puts it somewhere
    into windows directory and registers it with the graphics
    card. On startup the ProfileChooser takes the default profile
    and loads it into graphics card. That means that I am able
    to see accurate colors with applications that are not
    color managed - web browser, ...

    What I do not understand is what happens when I edit the
    photo in Photoshop Elements (I do not have the 'big' PS,
    so I am not sure whether this is different there). If it
    also uses the default profile taken from windows,
    I get double color-managing. And I think this is really
    the case - when I open the same image in the PSE and
    in the default browser, it looks that the result is not
    the same - there are subtle differences in skin tones.

    How is this supposed to work? Is there any way to have
    both the non-managed and managed applications to display
    the same (i.e. let the Profile Chooser load the lookup
    tables and tell the Photoshop etc. to use sRGB or whatever
    the display expects when the conversion is done down
    in the LUT)? Or does the PSE _always_ use the default
    monitor profile, whatever that is?

    Thanks
    --
    Stano
    Stanislav Meduna, Dec 19, 2005
    #1
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  2. On Mon, 19 Dec 2005 10:04:53 +0100, in rec.photo.digital Stanislav Meduna
    <> wrote:

    >Hi,
    >
    >I bought a Colorvision Spyder and calibrated my monitor.
    >It really helped. However, I am not really sure how this
    >works and I fear I might be double-color-managing.
    >
    >The Spyder generates an ICC profile, puts it somewhere
    >into windows directory and registers it with the graphics
    >card. On startup the ProfileChooser takes the default profile
    >and loads it into graphics card. That means that I am able
    >to see accurate colors with applications that are not
    >color managed - web browser, ...


    I thought this was the case as well, but was corrected by Bill Hilton. The
    colors on non-managed apps will be better, but not as good as in a color
    managed app.

    >What I do not understand is what happens when I edit the
    >photo in Photoshop Elements (I do not have the 'big' PS,
    >so I am not sure whether this is different there). If it
    >also uses the default profile taken from windows,
    >I get double color-managing. And I think this is really
    >the case - when I open the same image in the PSE and
    >in the default browser, it looks that the result is not
    >the same - there are subtle differences in skin tones.
    >
    >How is this supposed to work? Is there any way to have
    >both the non-managed and managed applications to display
    >the same (i.e. let the Profile Chooser load the lookup
    >tables and tell the Photoshop etc. to use sRGB or whatever
    >the display expects when the conversion is done down
    >in the LUT)? Or does the PSE _always_ use the default
    >monitor profile, whatever that is?


    How do you have color management set in PSE? IIRC, by default PSE3, which
    I'm using a bit, sets full color management and uses the Adobe RGB color
    space. So you will see a difference . No double color management there.
    What you don't want to do is double manage prints. Either use in the
    application you are printing from or the print driver, but not both.
    --
    Ed Ruf Lifetime AMA# 344007 ()
    See images taken with my CP-990/5700 & D70 at
    http://edwardgruf.com/Digital_Photography/General/index.html
    Ed Ruf (REPLY to E-MAIL IN SIG!), Dec 19, 2005
    #2
    1. Advertising

  3. Ed Ruf (REPLY to E-MAIL IN SIG!) wrote:

    > I thought this was the case as well, but was corrected by Bill Hilton. The
    > colors on non-managed apps will be better, but not as good as in a color
    > managed app.


    Hmm...

    > How do you have color management set in PSE? IIRC, by default PSE3, which
    > I'm using a bit, sets full color management and uses the Adobe RGB color
    > space.


    Yes, that's how I am using this.

    > So you will see a difference .


    Ahhhh .. yes, you are right, it can well be that I compared
    the picture that is in the Adobe RGB space - so that's why
    I saw the difference.. OK, I'll repeat my tests with sRGB
    picture and PSE set to sRGB space. Then the colors should
    be the same in the PSE and other browsers, right?

    > What you don't want to do is double manage prints. Either use in the
    > application you are printing from or the print driver, but not both.


    Yup. In fact I am trying to get the closest match possible
    with my printer (Epson 1800) and regardless of what I am
    using, I am still getting visible differences in exactly
    the same colors, that the spyder touches the most.

    Being a technical type, I would still like to fully understand
    how the PSE, display profile and ProfileChooser play together
    in this scenario - does anyone have a pointer to some technical
    resources? Maybe I also try to contact Colorvision, as only
    they know for sure what the ProfileChooser does.

    Thanks
    --
    Stano
    Stanislav Meduna, Dec 19, 2005
    #3
  4. Stanislav Meduna

    Tesco News Guest

    "Stanislav Meduna" <> wrote in message
    news:do5t3g$1gfp$...
    > Hi,
    >
    > I bought a Colorvision Spyder and calibrated my monitor.
    > It really helped. However, I am not really sure how this
    > works and I fear I might be double-color-managing.
    >
    > The Spyder generates an ICC profile, puts it somewhere
    > into windows directory and registers it with the graphics
    > card. On startup the ProfileChooser takes the default profile
    > and loads it into graphics card. That means that I am able
    > to see accurate colors with applications that are not
    > color managed - web browser, ...
    >
    > What I do not understand is what happens when I edit the
    > photo in Photoshop Elements (I do not have the 'big' PS,
    > so I am not sure whether this is different there). If it
    > also uses the default profile taken from windows,
    > I get double color-managing. And I think this is really
    > the case - when I open the same image in the PSE and
    > in the default browser, it looks that the result is not
    > the same - there are subtle differences in skin tones.
    >
    > How is this supposed to work? Is there any way to have
    > both the non-managed and managed applications to display
    > the same (i.e. let the Profile Chooser load the lookup
    > tables and tell the Photoshop etc. to use sRGB or whatever
    > the display expects when the conversion is done down
    > in the LUT)? Or does the PSE _always_ use the default
    > monitor profile, whatever that is?
    >
    > Thanks
    > --
    > Stano


    Hi there.

    You are, like a great many other people, getting a little mixed up between
    your Monitor Profile and the Working Space Profile.

    Your Monitor Profile, "Spyder"ed one, is only for showing the corrected
    colours on the screen. It adjusts the numbers from the Working Space
    Profile ( Adobe RGB) to correct for any inherent errors in the colours your
    Monitor would show.

    Your Spyder software should have put the profile into the correct folder,
    and made it the "Default" Monitor Profile. Check this in Display Properties
    > Settings >Advanced > Colour Management. It should be the only profile

    there, and it should be set as "Default".

    Any problems with Colour, could be due to Adobe Gamma. You need to remove
    that from the "Start Up" Folder, because otherwise it will probably try to
    adjust the Monitor Colour, Double Profiling.

    You also need to get a Printer Profile, to ensure that your Printer gives
    you the correct colours.

    If your Scanner or Camera can not be set to "Tag" your images with Adobe RGB
    as the Working Space Profile, or can not "Tag" any Profile, then they are
    almost certainly working in sRGB.

    The big problem with Elements is that you can not select which Profile to
    use as Working Space, it just seems to
    use Adobe RGB.

    There will always be some differences in Colour between what you see on
    Screen and what comes out of the Printer. In the Big PS you can use "Soft
    Proof" to show what it will look like using the Printer Profile for whatever
    Paper you plan to Print on. That is much closer, but is still not exact.

    Roy G
    Tesco News, Dec 19, 2005
    #4
  5. >> I thought this was the case as well, but was corrected by Bill Hilton. The
    >>colors on non-managed apps will be better, but not as good as in a color
    >>managed app.

    >
    > Ahhhh .. yes, you are right, it can well be that I compared
    > the picture that is in the Adobe RGB space - so that's why
    > I saw the difference.. OK, I'll repeat my tests with sRGB
    > picture and PSE set to sRGB space. Then the colors should
    > be the same in the PSE and other browsers, right?


    No. Having a profiled monitor means that any application that uses
    colour management "knows" what the screen looks like. That means the
    application can adjust its colour output such that it can show you what
    your image will look like on any other device (such as a printer)
    provided the application also has access to an accurate profile for the
    other device.

    Your web browser doesn't take note of colour profiles. It will make no
    effort to adjust its output to match PSE or any other application. It
    just throws the image onto the screen. If you want to see your image the
    same in Photoshop and your browser, you have to tell Photoshop that's
    what you want. Then Photoshop will also "throw the image onto the
    screen" without fussing over profiles. Under the full Photoshop you do
    that by selecting "Monitor RGB" as your soft-proof colour space. I'm not
    sure how it works under PSE.
    Derek Fountain, Dec 19, 2005
    #5
  6. Tesco News wrote:

    > Your Monitor Profile, "Spyder"ed one, is only for showing the corrected
    > colours on the screen. It adjusts the numbers from the Working Space
    > Profile ( Adobe RGB) to correct for any inherent errors in the colours your
    > Monitor would show.


    OK, maybe this is something that I don't understand. My expectation
    is that first the working space (whatever that is, sRGB or Adobe RGB)
    gets converted to something independent (CIE Lab), using the
    Adobe RGB ICC. Then this gets converted to whatever the monitor
    expects using the monitor ICC. Am I right? Or does the PSE simply
    feed the display with whatever binary pixel values it currently
    has, expecting the graphics card to take care of that using the
    Spyder-ed data?

    > Your Spyder software should have put the profile into the correct folder,
    > and made it the "Default" Monitor Profile. Check this in Display Properties
    > > Settings >Advanced > Colour Management. It should be the only profile

    > there, and it should be set as "Default".


    It is not the only one (I created profiles for two displays and more
    brightness settings), but it is the default one.

    > Any problems with Colour, could be due to Adobe Gamma. You need to remove
    > that from the "Start Up" Folder, because otherwise it will probably try to
    > adjust the Monitor Colour, Double Profiling.


    Yup, did that already.

    > You also need to get a Printer Profile, to ensure that your Printer gives
    > you the correct colours.


    The Epson R1800 has a set of profiles and various other options -
    I got the best match setting the printer to 'Adobe RGB' with gamma 2.2
    and using that as printer profile. Next best was the profile suplied
    by Epson, applied by the PS (with color mgmt disabled in printer
    driver). Something that can be downloaded from Epson as supposedly
    even better profile was worse. I am using original inks, original
    paper and printing mode that matches the profile.

    > If your Scanner or Camera can not be set to "Tag" your images with Adobe RGB
    > as the Working Space Profile, or can not "Tag" any Profile, then they are
    > almost certainly working in sRGB.


    My camera allows me to choose that - I shoot with Adobe RGB + embed
    profile. However, at this moment I am trying to match display
    and printer - these things come later. The test image I tried
    to view and print is tagged with Adobe RGB.

    > The big problem with Elements is that you can not select which Profile to
    > use as Working Space, it just seems to use Adobe RGB.


    Aha. Does it matter for colors well within the gamut of both
    the display and printer?

    > There will always be some differences in Colour between what you see on
    > Screen and what comes out of the Printer. In the Big PS you can use "Soft
    > Proof" to show what it will look like using the Printer Profile for whatever
    > Paper you plan to Print on. That is much closer, but is still not exact.


    Interesting. What exactly does this soft proof mode do (in terms
    of what profile gets applied when)?

    Thanks
    --
    Stano
    Stanislav Meduna, Dec 19, 2005
    #6
  7. Stanislav Meduna

    Bill Hilton Guest

    > Roy G writes ...
    >
    >The big problem with Elements is that you can not select which Profile
    >to use as Working Space, it just seems to use Adobe RGB.


    Edit - Color Settings lets you pick between 'no color management',
    'limited color management' (sRGB) or 'full color management'
    (AdobeRGB). I think it actually defaults to sRGB and you have to
    change it to get AdobeRGB (this is with Elements 3, may be different
    with 4 or 2).

    Also, if you open a file in a different color space like, say,
    Ektaspace, it recognizes the profile and lets you work in that space
    for that file.

    Bill
    Bill Hilton, Dec 19, 2005
    #7
  8. Stanislav Meduna

    Bill Hilton Guest

    > Stano writes ...
    >
    >What exactly does this soft proof mode do (in terms
    >of what profile gets applied when)?


    When you print a file the RGB values get translated by the software
    into different numbers for the printer, ideally so that what spits out
    on the print ('hard proof') looks as close as possible to what you see
    on the screen. This translation is a basic concept behind the ICC
    color managment flow, explained well here
    ....http://www.creativepro.com/story/feature/13605.html

    What 'soft proofing' does is try to emulate what the final print will
    look like by changing the brightness and colors on the screen to mimic
    how the final print will appear. So you have a 'soft proof' on the
    monitor and after you apply the printer profile you can make edits for
    contrast and color for that particular paper/ink profile, if necessary
    (usually best to put these in a separate layer set).

    If you have a good monitor, accurate monitor profile and accurate
    printer profiles then you can usually get 90-98% accuracy, but there
    are a lot of bad profiles floating around so for many people it doesn't
    work accurately. Here's an article explaining it in more detail ...
    http://www.creativepro.com/story/feature/10150.html?origin=story

    This feature was added in Photoshop 6 and Elements typically lags
    Photoshop in features by 2-3 versions, so maybe Adobe has included it
    with V 4 or perhaps in V 5 (it's not in Elements 3).

    Bill
    Bill Hilton, Dec 19, 2005
    #8
  9. Stanislav Meduna

    Tesco News Guest

    "Bill Hilton" <> wrote in message
    news:...
    >> Roy G writes ...
    >>
    >>The big problem with Elements is that you can not select which Profile
    >>to use as Working Space, it just seems to use Adobe RGB.

    >
    > Edit - Color Settings lets you pick between 'no color management',
    > 'limited color management' (sRGB) or 'full color management'
    > (AdobeRGB). I think it actually defaults to sRGB and you have to
    > change it to get AdobeRGB (this is with Elements 3, may be different
    > with 4 or 2).
    >
    > Also, if you open a file in a different color space like, say,
    > Ektaspace, it recognizes the profile and lets you work in that space
    > for that file.
    >
    > Bill


    Thanks Bill.

    That is what I originally suspected Elements was doing, but recently while
    using it on my daughters machine, all her images seemed to be Tagged with
    Adobe RGB. Yet, after bringing some of them home, Ps brought up the
    Untagged Dialogue when opening them.

    I normally use Ps CS on my own machine, and gave her Elements 2 which I got
    free with a scanner, so I am not very expert with it.

    Roy G
    Tesco News, Dec 19, 2005
    #9
  10. Stanislav Meduna

    Bill Hilton Guest

    > Roy G writes ...
    >
    >recently while using it (Elements 2) on my daughters machine, all
    >her images seemed to be Tagged with Adobe RGB. Yet, after
    >bringing some of them home, Ps brought up the
    >Untagged Dialogue when opening them.


    In Elements 3 when you do a Save As (and probably 'save' as well)
    there's a check box for 'Save Options - Color: ICC Profile' and if this
    is checked it seems to attach the named profile, which Photoshop then
    picks up. So maybe this is unchecked on your daughter's machine or
    maybe Elements 2 is different than 3 on this.

    > I normally use Ps CS on my own machine, and gave her Elements 2 which
    >I got free with a scanner, so I am not very expert with it.


    I'm in the same boat, a Photoshop user since V 4 with several bundled
    copies of Elements that came with scanners and digital cameras. A
    friend is a newbie to digital stuff and got Elements free with his
    scanner so I loaded one of my copies and tried to help him learn the
    basics, but I'm not very good with it either :)

    Bill
    Bill Hilton, Dec 19, 2005
    #10
  11. In article <do5t3g$1gfp$>, says...
    > Hi,
    >
    > I bought a Colorvision Spyder and calibrated my monitor.
    > It really helped. However, I am not really sure how this
    > works and I fear I might be double-color-managing.
    >
    > The Spyder generates an ICC profile, puts it somewhere
    > into windows directory and registers it with the graphics
    > card. On startup the ProfileChooser takes the default profile
    > and loads it into graphics card. That means that I am able
    > to see accurate colors with applications that are not
    > color managed - web browser, ...
    >
    > What I do not understand is what happens when I edit the
    > photo in Photoshop Elements (I do not have the 'big' PS,
    > so I am not sure whether this is different there). If it
    > also uses the default profile taken from windows,
    > I get double color-managing. And I think this is really
    > the case - when I open the same image in the PSE and
    > in the default browser, it looks that the result is not
    > the same - there are subtle differences in skin tones.
    >
    > How is this supposed to work? Is there any way to have
    > both the non-managed and managed applications to display
    > the same (i.e. let the Profile Chooser load the lookup
    > tables and tell the Photoshop etc. to use sRGB or whatever
    > the display expects when the conversion is done down
    > in the LUT)? Or does the PSE _always_ use the default
    > monitor profile, whatever that is?
    >
    > Thanks
    >

    I'll just paste a reply that I posted recently - this is quite a common
    misunderstanding and concerns the difference between calibration and a
    monitor profile. Sorry if it's a bit long...

    Creating a monitor profile has 2 parts:
    1 - Calibration: the display is adjusted (via settings in the graphics
    card and maybe the monitor controls) to get things like colour
    temperature, gamma etc. correct. All applications see the effect of the
    calibration - this is what gets loaded to the graphics card when the
    system starts up.
    2 - Profiling: the response of the calibrated display is accurately
    measured to create a profile of how it displays colour. This profile is
    used by profile-aware applications to adjust the colours sent to the
    graphics card and monitor. Without these adjustments, the colour
    displayed will not be accurate.

    Photoshop or PSE, as you can imagine, is profile-aware and displays
    accurate colour. Most other applications (e.g. web browsers, Windows
    itself) are not profile-aware, do not correct the colours sent to the
    graphics card, and do not display accurate colour. That is why you are
    seeing a difference.

    Unfortunately (unless your PC is a Mac!), if you want a profiled monitor
    you have to put up with a difference between Photoshop/PSE and most
    other applications. Photoshop/PSE is correct :)
    Graeme Cogger, Dec 19, 2005
    #11
  12. On Mon, 19 Dec 2005 05:12:12 -0500, "Ed Ruf (REPLY to E-MAIL IN
    SIG!)" <> wrote:

    >On Mon, 19 Dec 2005 10:04:53 +0100, in rec.photo.digital Stanislav Meduna
    ><> wrote:

    ....
    >>The Spyder generates an ICC profile, puts it somewhere
    >>into windows directory and registers it with the graphics
    >>card. On startup the ProfileChooser takes the default profile
    >>and loads it into graphics card. That means that I am able
    >>to see accurate colors with applications that are not
    >>color managed - web browser, ...

    >
    > I thought this was the case as well, but was corrected by Bill Hilton. The
    >colors on non-managed apps will be better, but not as good as in a color
    >managed app.


    Just checking... What part of the original post needs to be
    "corrected"?

    I think it is true that a spyder app, or Adobe Gamma, or a third-party
    monitor adjustment app, will make a profile and register it with the
    OS. And that Adobe Gamma Loader, or a third-party equivalent, will set
    graphics card registers at startup so that the "profiled" monitor
    shows an sRGB image from any application (or the OS itself) correctly
    without any intentional color management. ("Correctly" being to the
    limits of whatever process created the profile in the first place, of
    course.)

    Does a color-managed app fed an sRGB image add any accuracy to this
    process? It can't be changing the graphics card registers, or you
    would see all the other open windows change color when it took
    control. So the color-managed app must be sending unmodified sRGB to
    the graphics card, just like a browser would.

    Granted, if fed an image in any other color space, the color-managed
    app will provide more accurate rendering by intelligently converting
    it to the monitor space. Is there any other advantage?

    Loren
    Loren Amelang, Dec 19, 2005
    #12
  13. In article <>,
    says...
    > On Mon, 19 Dec 2005 05:12:12 -0500, "Ed Ruf (REPLY to E-MAIL IN
    > SIG!)" <> wrote:
    >
    > Just checking... What part of the original post needs to be
    > "corrected"?
    >
    > I think it is true that a spyder app, or Adobe Gamma, or a third-party
    > monitor adjustment app, will make a profile and register it with the
    > OS. And that Adobe Gamma Loader, or a third-party equivalent, will set
    > graphics card registers at startup so that the "profiled" monitor
    > shows an sRGB image from any application (or the OS itself) correctly
    > without any intentional color management. ("Correctly" being to the
    > limits of whatever process created the profile in the first place, of
    > course.)
    >


    No - only a colour management aware app will show the colours correctly.
    The RGB values sent to the graphics card need to be adjusted to account
    for the monitor profile. Adobe Gamma Loader will only load a
    calibration LookUp Table (LUT) to the card, but that is just a starting
    point for the colour management process. sRGB is irrelevant (see
    below).

    > Does a color-managed app fed an sRGB image add any accuracy to this
    > process? It can't be changing the graphics card registers, or you
    > would see all the other open windows change color when it took
    > control. So the color-managed app must be sending unmodified sRGB to
    > the graphics card, just like a browser would.
    >


    It converts the colours from the sRGB space to the monitor profile
    before sending them to the graphics card. A browser does no conversion
    and sends the RGB values "as is"..

    > Granted, if fed an image in any other color space, the color-managed
    > app will provide more accurate rendering by intelligently converting
    > it to the monitor space. Is there any other advantage?
    >


    sRGB is just another colour space, in the same way as AdobeRGB or
    ProPhoto RGB. There is nothing special about it, and the same arguments
    apply for all working spaces.

    I suggest you read my other post elsewhere in the thread - I have tried
    to explain how monitor profiles work and the difference between
    calibration and profiling.

    > Loren
    >
    Graeme Cogger, Dec 19, 2005
    #13
  14. Stanislav Meduna

    Bill Hilton Guest

    >>> Stanislav Meduna
    >>> The Spyder generates an ICC profile ... (this) means that I
    >>> am able to see accurate colors with applications that are not
    >>> color managed - web browser, ...


    >> Ed Ruf wrote
    >> I thought this was the case as well, but was corrected by Bill Hilton.
    >> The colors on non-managed apps will be better, but not as good as
    >> in a color managed app.


    >Loren wrote ...
    >Just checking... What part of the original post needs to be
    >"corrected"?


    The part about "I am able to see accurate colors with applications that
    are not color managed". These apps don't 'convert' the RGB numbers to
    get the most accurate colors using the icc profile, while the ICC apps
    that recognize monitor profiles do.

    > Does a color-managed app fed an sRGB image add any accuracy to
    > this process?


    Yes ... as Graeme wrote, all apps benefit from the 'calibration' stage
    where you define the gamma and set a white and black point, but then
    the profiling software displays color patches on the screen and the
    puck measures them and creates a matrix file that enables programs that
    recognize monitor profiles to display colors more accurately.

    As a theoretical example, most CRT monitors are built such that full or
    near full values of the RGB guns give a 9300 K white point but
    typically we use 5000 K or 6500 K and to get these warmer colors the
    blue and to a lesser extent the green guns are reduced ... to make
    something up that I once saw on an older monitor, say 98% R, 80% G, 65%
    B to get 5000 K ... this is for the white point, but now it's harder to
    get a linear gray, meaning equal RGB values of say 64/64/64 or
    150/150/150 are neutral by definition in a 'working space' like sRGB,
    but are harder to hit the more uneven the RGB gun values are (like in
    the example I gave). So there's often a slight color cast in the
    neutrals in non-color managed apps, while this is corrected for in apps
    that recognize the profile.

    You can turn recognition of the monitor profile on/off in Photoshop
    with a keystroke and if I look at a pattern like this one ...
    members.aol.com/bhilton665/colors.jpg ... and disable/enable the
    monitor profile what I see on my monitor is that most of the squares
    look the same but the saturated colors across the top shift noticeably
    in the reds, yellows and oranges. I came across this when web photos
    from Arizona and Utah's Red Rock country looked different than even
    sRGB images in Photoshop as the reds dulled down. Images that weren't
    first converted to sRGB looked much duller, but you still see a 2nd
    level effect just from the lack of monitor profile recognition.

    Bill
    Bill Hilton, Dec 19, 2005
    #14
  15. Stanislav Meduna

    Bill Hilton Guest

    >> Loren writes ...
    >> Granted, if fed an image in any other color space (other than
    >> sRGB), the color-managed app will provide more accurate
    >> rendering by intelligently converting it to the monitor space.


    >Graeme writes ...
    >sRGB is just another colour space, in the same way as AdobeRGB or
    >ProPhoto RGB. There is nothing special about it, and the same
    >arguments apply for all working spaces.


    Actually if you view an sRGB file without the profile (like in a web
    browser) there's not much change, but if you view the same file with a
    much wider color space in a non-color managed app then the colors can
    look REALLY bad ... at least I think that's what Loren is getting at.

    Here's an example of a red bird, converted to ProPhoto from the RAW
    (this is a very wide space, much wider than AdobeRGB) ... this shows
    what the file looks like if I convert to sRGB and then make an untagged
    jpeg ...
    http://members.aol.com/bhilton665/card_srgb.jpg ... and here's what it
    looks like if I just take the ProPhoto tagged file and convert to jpeg
    without dumbing it down to sRGB first ... all the saturated colors get
    dropped and it looks really really bad ...
    http://members.aol.com/bhilton665/card_prophoto.jpg

    Granted ProPhoto is a really extreme working space but even with
    AdobeRGB you'll see a lot of saturated colors fall out. I think that's
    what Loren was getting at.

    Bill
    Bill Hilton, Dec 19, 2005
    #15
  16. Graeme Cogger wrote:

    > Creating a monitor profile has 2 parts:
    > 1 - Calibration: the display is adjusted (via settings in the graphics
    > card and maybe the monitor controls) to get things like colour
    > temperature, gamma etc. correct. All applications see the effect of the
    > calibration - this is what gets loaded to the graphics card when the
    > system starts up.
    > 2 - Profiling: the response of the calibrated display is accurately
    > measured to create a profile of how it displays colour. This profile is
    > used by profile-aware applications to adjust the colours sent to the
    > graphics card and monitor. Without these adjustments, the colour
    > displayed will not be accurate.


    Thanks! - that finally makes sense. So the .icc file generated
    by the Spyder has actually two parts:

    - LUT data tht gets loaded to the card via ProfileChooser
    - profile that is used by the PS (and QImage and that's
    probably all on my system)

    Is the LUT part also standardized somehow? I am asking because
    the ProfileChooser refuses to use a profile that it did not
    create itself - maybe because it is in some proprietary
    format embedded in the vendor-specific part of the ICC?


    Thanks to all that responded.

    Regards
    --
    Stano
    Stanislav Meduna, Dec 20, 2005
    #16
  17. On 19 Dec 2005 15:28:18 -0800, "Bill Hilton" <>
    wrote:

    >>>> Stanislav Meduna
    >>>> The Spyder generates an ICC profile ... (this) means that I
    >>>> am able to see accurate colors with applications that are not
    >>>> color managed - web browser, ...

    >
    >>> Ed Ruf wrote
    >>> I thought this was the case as well, but was corrected by Bill Hilton.
    >>> The colors on non-managed apps will be better, but not as good as
    >>> in a color managed app.

    >
    >>Loren wrote ...
    >>Just checking... What part of the original post needs to be
    >>"corrected"?

    >
    >The part about "I am able to see accurate colors with applications that
    >are not color managed". These apps don't 'convert' the RGB numbers to
    >get the most accurate colors using the icc profile, while the ICC apps
    >that recognize monitor profiles do.
    >
    >> Does a color-managed app fed an sRGB image add any accuracy to
    >> this process?

    >
    >Yes ... as Graeme wrote, all apps benefit from the 'calibration' stage
    >where you define the gamma and set a white and black point, but then
    >the profiling software displays color patches on the screen and the
    >puck measures them and creates a matrix file that enables programs that
    >recognize monitor profiles to display colors more accurately.


    To further check my understanding (or confusion) here...

    Am I correct that this "matrix file" is what gets loaded to the lookup
    table registers on the graphics card? Or is it a separate color
    translation containing subtle differences between what was achieved by
    customizing the graphics card lookup table and what the spyder saw?

    Maybe I'm behind the state of the art here, but as I understand it,
    the graphics card lookup table translates between the three 8-bit
    values sent by the application for each pixel, and the three 8-bit
    values that get sent on to the monitor to show that pixel "correctly".
    If all you have to work with is eight bits, and the graphics card
    lookup table has already been set up optimally, what can a color
    managed app add to that for an image that is already in the native
    color space?

    My thinking here is largely based on my experience with an older
    notebook where the backlight has gone seriously "warm", to the point
    where color errors are obvious. I wasn't able to fix this with Adobe
    Gamma, for images inside or outside PS, and concluded Adobe Gamma had
    somehow stopped working. I found WiziWYG and it let me tweak the
    colors back to some semblance of decency. You can clearly see it load
    the graphics registers when its loader runs at startup, and the effect
    seems to be the same both inside and outside of PS (though on a
    notebook screen maybe the subtleties just aren't visible).

    Of course a spyder could do a much better job than I did, and optimize
    many more points along each color's correction curve. But wouldn't it
    load its conclusions into the graphics registers just like my manual
    curves get loaded? And since there are only eight bits per color to
    play with, how could a color managed app improve on that? (Unless the
    original image needs to be converted to the native color space, of
    course.)

    I still don't understand what happened to Adobe Gamma, though. It
    didn't appear to be able to do anything to help my problem, color
    managed app or not. I even tried reloading fresh versions from the CD
    and from the web. Does it function differently from WiziWYG?

    Loren
    Loren Amelang, Dec 20, 2005
    #17
  18. In article <>,
    says...
    > On 19 Dec 2005 15:28:18 -0800, "Bill Hilton" <>
    > wrote:
    >
    > >>Loren wrote ...
    > >>Just checking... What part of the original post needs to be
    > >>"corrected"?

    > >
    > >The part about "I am able to see accurate colors with applications that
    > >are not color managed". These apps don't 'convert' the RGB numbers to
    > >get the most accurate colors using the icc profile, while the ICC apps
    > >that recognize monitor profiles do.
    > >
    > >> Does a color-managed app fed an sRGB image add any accuracy to
    > >> this process?

    > >
    > >Yes ... as Graeme wrote, all apps benefit from the 'calibration' stage
    > >where you define the gamma and set a white and black point, but then
    > >the profiling software displays color patches on the screen and the
    > >puck measures them and creates a matrix file that enables programs that
    > >recognize monitor profiles to display colors more accurately.

    >
    > To further check my understanding (or confusion) here...
    >
    > Am I correct that this "matrix file" is what gets loaded to the lookup
    > table registers on the graphics card? Or is it a separate color
    > translation containing subtle differences between what was achieved by
    > customizing the graphics card lookup table and what the spyder saw?
    >


    No, it's separate. The graphics card loads 3 basic curves - one each
    for R, G, B. There are 2 main reasons why this is not enough:

    - The graphics card knows nothing about the colour space of the original
    file, and therefore cannot compensate accordingly. For example, an RGB
    value of (200,50,20) in the AdobeRGB space is a different colour to
    (200,50,20) in sRGB. If you feed (200,50,20) to the graphics card, it
    won't know what colour it needs to display.

    - The graphics card Look-Up Table (LUT) has independent curves for R, G
    and B. Say you have a monitor that displays greys perfectly, but makes
    bright purple, e.g. (200,10,200), appear somewhat blue. The purple
    problem can be cured if an R value of 200 is translated to 210 and a B
    value of 200 is translated to 190. However, this now means that a pure
    grey (200,200,200) will be displayed as (210,200,190) and appear a
    little orange. Instead of independent RGB curves, a monitor profile
    uses a 3D table and can correct for these issues.

    <snip>
    Graeme Cogger, Dec 20, 2005
    #18
  19. In article <do9nrg$e23$>, says...
    > Graeme Cogger wrote:
    >
    > > Creating a monitor profile has 2 parts:
    > > 1 - Calibration: the display is adjusted (via settings in the graphics
    > > card and maybe the monitor controls) to get things like colour
    > > temperature, gamma etc. correct. All applications see the effect of the
    > > calibration - this is what gets loaded to the graphics card when the
    > > system starts up.
    > > 2 - Profiling: the response of the calibrated display is accurately
    > > measured to create a profile of how it displays colour. This profile is
    > > used by profile-aware applications to adjust the colours sent to the
    > > graphics card and monitor. Without these adjustments, the colour
    > > displayed will not be accurate.

    >
    > Thanks! - that finally makes sense. So the .icc file generated
    > by the Spyder has actually two parts:
    >
    > - LUT data tht gets loaded to the card via ProfileChooser
    > - profile that is used by the PS (and QImage and that's
    > probably all on my system)
    >


    That's correct :)

    > Is the LUT part also standardized somehow? I am asking because
    > the ProfileChooser refuses to use a profile that it did not
    > create itself - maybe because it is in some proprietary
    > format embedded in the vendor-specific part of the ICC?
    >


    Unfortunately, the LUT is not standardised. The ICC file format is
    basically a set of named tags, and the tags used for the profile itself
    are well defined and standardised. There can also be optional tags for
    other purposes, which are ignored by colour management engines. Most
    profilers use a tag called 'vcgt' to store the LUT, but the way the data
    is stored within the tag is different for different apps.

    >
    > Thanks to all that responded.
    >
    > Regards
    >
    Graeme Cogger, Dec 20, 2005
    #19
  20. Stanislav Meduna

    Bill Hilton Guest

    > Loren wrote ...
    >
    >Am I correct that this "matrix file" is what gets loaded to the
    >lookup table registers on the graphics card?


    Graeme answered that well ...

    >My thinking here is largely based on my experience with an older
    >notebook where the backlight has gone seriously "warm", to the point
    >where color errors are obvious. I wasn't able to fix this with Adobe
    >Gamma ... I still don't understand what happened to Adobe Gamma,
    >though. It didn't appear to be able to do anything to help my problem,
    >color managed app or not.


    Adobe Gamma does a very poor job with LCDs and laptops ... I thought
    this was mentioned in the documentation. Even the original Spyder does
    poorly with laptops ... if you're trying to do color-critical work on a
    laptop you need to spend $200 or so and get the Eye-One or the Sypder 2
    or the Monaco (Optix?) ...

    Bill
    Bill Hilton, Dec 20, 2005
    #20
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