[argyllcms] Re: Strange results on a projector
- From: Frédéric <frederic.mantegazza@xxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 19 Feb 2008 14:23:16 +0100 (CET)
Le 19/2/2008, "Graeme Gill" <graeme@xxxxxxxxxxxxx> a écrit:
>I've not personally seen this, but then I haven't done much projector
>calibration/profiling. Are you sure it's an LCD, and not (say) a 4 color
>segment (R,G,B and White) DLP ?
I have to check, but I'm pretty sure this is a LCD (we can see the 3
signals when we are very close to the screen). But it is not a last
generation one... Could it also be a too-old-light problem?
>If a device is actually additive, then unless the primaries are in
>very strange locations, it should behave itself reasonably once the
>per channel curves have been adjusted to give a neutral. The main
>mechanism for non-additive behaviour in a modern projector
>would be that something electronic is manipulating it.
>A 4 segment DLP has such manipulations, or maybe some projectors
>have various "enhancement" modes that mess with things, and make
>the basic RGB behaviour non-additive.
>
>If the behaviour is dynamic (as some enhancement modes are),
>then color management is basically useless. If it static, then
>the classic answer using color management is to characterize
>the device, and then color correct the slides. For non-additive
>behaviour a LUT based profile would be needed.
Thanks for these usefull explanations. My personnal projector is a
Yamaha, and I know it uses a yellow filter. That's why I got strange
results when I tried to calibrate it. But our club projector is a
4-color DLP, and the calibration worked well. So the white does not seem
to be a problem (at least with this one).
>If this isn't an option open to you (and it does take some
>messing around), does the projector have a mode that is
>better behaved ?
I don't think so; as I said, it is very basic.
>I understand (for instance) that many 4 color
>segment DLP's have a 3 segment (RGB) mode, that is not as bright
>but gives a bigger gamut and would probably behave better from
>a color management point of view. If it's some other type of
>projector, them maybe it also has a better behaved mode.
I didn't know that! I'll check if our club projector has such mode.
>Do you know what the make and model are ?
I asked the friend to send me the exact model name, and I will find the
complete documentation.
--
Frédéric
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