Problems with gammut mapping

Question

Hi folks.
My brother and I are trouble-shooting a colour management issue, but just don't get to the bottom of it. Any help would be greatly appreciated.
It seems as if Windows has troubles setting the monitor profile, or at least communicating this information to Photoshop. The problem is, that in some scenarios, Photoshop does NOT do the gammut mapping [working color space => monitor color space]. We have tested this on two machines.
The strange thins is, that on the MacBookPro (dual boot), Photoshop CS4 does the gammut mapping on Os X, but not on Win XP ... although the hardware is obviously identical.
On the Dell notebook (Win XP), things are equally strange, as the only way to have Photoshop (CS3 in this case) do the gammut mapping is to have an external monitor attached in dual-monitor-mode. No gammut mapping takes place, when internal or external display is used exclusively.
To sum it up:
MacBook   Pro (dual boot)
Os X + internal display
yes
Win XP + internal display
no
Dell Inspiron notebook
dual monitor set-up
yes
only external monitor
no
only internal monitor
no
We used the "color" control panel applet (wincolor.exe) and ("control panel >> Display properties >> settings >> advanced >> color management") to set the monitor profile.
Have you ever observed/heard similar things ?
Do you have any explanation ?
Thanks so much !!

Answer 1

Christian,
I loaded the ColorSpin profile in place of my standard monitor profile as my default Windows display profile (Display Properties/Settings/Advanced/Color Management) while Photoshop remained open.  Then, from within PS I looked at the monitor profile in the Color Settings RGB dropdown box and it continued to show the profile that was set as the OS default when PS was originally launched.  Yes, rebooting PS updates this dialog box to show the new default profile, in this case, Colorspin.
However, even without rebooting Photoshop, my color management is working perfectly and reflects the use of the new Windows default profile.  I can keep loading different profiles using Windows Display Properties, and Photoshop sees the new profile immediately, displaying colors accordingly.  Colorspin whacks the colors as one would expect.
Yes...Photoshop's color settings drop down box still shows the original monitor profile until PS is restarted.  Adobe should probably change the default monitor display in Color Settings so it updates without rebooting, but at least on my system, PS recognizes and uses the new profile immediately.  When PS initially boots, it looks at all the profiles, plugins, etc, so it probably loads that info in that drop down box and does not update it again until the program is restarted.
What monitor profiling software are you using?  Many monitor profiles contain a "vcgt" tag, which stores the calibration data, white point, gamma, etc,  that gets downloaded to the VLUT.  I know the monitor profiles I create with ProfileMaker and EyeOne Match contain this tag, but some other programs do not write this tag to the profile when it is created.  Without this tag, the calibration info may NOT be loaded in Windows, whereas I am pretty certain OSX sees it and adjusts automatically.  This is the reason a LUT loader is provided with many profling software packages, so the calibration data is properly loaded into the LUT.  To test this, download the free DisplayProfile.exe file from XRite and launch it.  It will list your available display profiles.  The ones with (*) directly after the profile name have the required vcgt tag, and if you click on one of those profiles, it will download the required data to your VLUT and you should see an immediate change in your monitor.  The profiles without the vcgt tag will not download calibration data to the VLUT using DisplayProfile and in all liklihood, your monitor display will not change at all. I know I am back to calibration and not remapping, but perhaps PS needs this to detect the new profile and use it?  Give it a try.
Lou