[argyllcms] Re: DELL Laptop RGBLED calibration

Marcello Desantis wrote:

The environment:
Dell M6400 with RGBLED WUXGA 16.7M colors display (wide gamut?)
Ubuntu 9.04

The problem:
Oversaturated and wrong colors


Hmm. Calibration probably won't fix this, since it strives
to regulate the behaviour of each channel independently,
rather than limit combinations of channel values. You can
change the white point using calibration, but this won't
fix oversaturation or wrong colors. To fix this,
some form of profile matching is needed.

The problem is that while calibration will be applied
to all the desktop elements, profiles generally aren't.

Typically wide gamut monitors have some internal setting
that lets them emulate a more conventional monitor to
reduce these sorts of problems (sRGB), but of course this largely
defeats the purpose of having a wide gamut monitor...


The target:
obtaining more natural colors with all my desktop apps (not only with
profile aware apps). I'm a software developer and I need to see the same
colors my customers are going to see.


Basically this is impossible unless the desktop is fully color
managed (ie., you can tell the window manager/theme engine what
source colorspace to use for the desktop elements, and it will
run these through the CMM to the display profile before
displaying them). Off hand, I'm not sure any desktops are except
perhaps OS X. The best you might find is a WM or theme manager that
lets you set a custom pallet for everything, and then convert
the colours to your wide gamut monitor space manually as a special
theme. You'd have to color convert all the bitmaps (icons etc.)
too though, and this doesn't fix other non-color managed
application content.


1) which instrument would you recommend? I'd go with Eye-One LT, which
seems (googling around) compatible with both Argyll and my LED/wide
gamut display. And what about Huey?


They're both good instruments, but may not work too well on a wide
gamut LED based monitor. Some colorimeter claim to be better at
this sort of thing (ie. Spyder 3 ??), but the only sure way would
be to use a spectrometer such as the ColorMunki or EyeOne Pro,
which you may find are too expensive for what you are after.


2) I've a small Vista installation on my laptop, just in case I need it
for troubleshooting (Dell doesn't support Ubuntu on my laptop). Can I
eventually run the device native calibrating software on windows and
then load the resulting profile in Ubuntu?


You can probably load the calibration across operating systems, yes.

I suspect that overall you are at the bleeding edge, and it is
only the introduction of such wide gamut monitors that is starting
people thinking about what to do about them (ie. Microsoft Vista may
cope better, I haven't checked). I would suspect even fewer people
in the Linux/X11 world are thinking about it. Someone was having
a go at adding color management to the X11 composting
manager which is an interesting approach to solving this sort
of problem, but I'm not sure where that project is at.

Graeme Gill.

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