[argyllcms] Re: widegamut LCDs and internal LUT

Hi Alexandre,
so far I'm not aware of any progress being made on this topic. When the thread was up on the list, I blogged on this ( http://colorhacks.blogspot.com/2008/02/monitors-with-internal-luts.html ). Basically, the tool ddccontrol could be used to read and write the monitor's LUTs - but for this the addresses and data format would be necessary. Probably it's very similar to the format of the video card LUTs, but that's just guessed.
And to be more specific: I don't think you will have luck with Eizo displays here since they connect to the PC via USB. In contrast to this, e.g. NEC displays use the standard VGA/DVI cable and you can use the standard DDC/CI commands.
To point 2 I would like to add, that this would certainly be nice for xcalib (@Graeme: you probably would agree on this for dispwin as well ;) ) but so far it's unclear for me how to add this without a certain amount of DDC/CI support inside xcalib. Probably the first step would be to extedn ddccontrol and then see how easily this could be moved/copied to xcalib. And in addition to the work needed, it's unclear to me how general this really is: there's no single standard so far how to achieve this - in terms of how the information is stored inside an ICC profile and how the display is accessed. 

- Stefan


Alexandre Prokoudine wrote:

Hi,

I'm choosing between EIZO FlexScan SX2461W and LaCie 324 for a new
workstation (mostly photography). I read the thread on internal LUT
support from February'08 (in this mailing list) and it looks like no
open source software is still able to talk to guts of widegamut LCDs
via DDC.

So, three questions:

1. How correct would be color reproduction on a modern Linux system
with such a display (if I have a, say, Intel X3100 with XRandr 1.2
support). What artifacts will I see? Staircase in gradients? Shifted
hues?

2. From what I can see xcalib/xicc cannot work with displays inner
LUTs as well. How do I work around it? Do I work around it at all?

3. Are there any news regarding what I misleadingly call "support for
internal LUT"? :-) And is there anything I could do to help improving
the situation (sending a display to Graeme is not an option at this
time, sorry)?

Alexandre

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