[argyllcms] Re: Argyll-reset and Windows-reset gamma curves
- From: Graeme Gill <graeme@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Mon, 12 Aug 2013 11:05:42 +1000
Ivan Kolesov wrote:
> I guess the bottom line is, this mangling happens only when the gamma ramp
> is read 'directly from hardware', whatever that means in terms of coding.
> Otherwise it works like it should.
It comes down to whether the HW only has 8 bit entries. I guess it's possible
that some DVI out only cards may be built that way, although I would have
thought that a lot of them would have VGA as a fallback over DVI as well,
and hence may have > 8 bit entries.
It's also possible that Powerstrip has bugs in this area, just like Windows.
> I also
> wonder if Nvidia cards have this problem as well. Maybe if someone could
> check this...
I'm not sure how this would apply to NVidia cards. On my card at least,
the on screen utility lets you fiddle per channel curves, but any
such adjustments don't seem to be reflected in the VideoLUT data that
the OS sees. It's "load ICC profile" is simply weird - it seems to
load the profile per channel curves (NOT 'vcgt' tag curves), which
is simply nonsense.
Graeme Gill.
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