[argyllcms] Re: Compatibility with i1 (Eye One) Display Pro 3 retail and OEM?
- From: Graeme Gill <graeme@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Fri, 17 Feb 2012 11:09:35 +1100
János, Tóth F. wrote:
> A ccss with RGB only (I created it from RGBW measurement and deleted
> the last entry) will make dispcal to crash.
Hmm. I don't see a crash (just an error) when I try this,
but there are a couple of bugs in xicc/ccxx.c where
it rejects a file with less than 4 samples. I'll fix this.
> A ccss with RGBW is closer to the ccmx from RGB.
> A matrix from RGB seems to give a nice match to the spectro even if
> the display isn't additive. (But it can be tricky if not practically
> impossible to work around the faulty DSP and measure the native RGB
> primaries...)
I'm not sure that your results are due to the purity of the primaries,
or whether in fact it is the nature of the mathematics. It could be
that including a heavily weighted white makes the calibration matrix
computation less stable (making it more sensitive to measurement errors),
while using just well separated samples (RGB) makes the
calibration solution more mathematically robust. If the latter is
the case, then exactly how pure the RGB measurements are won't make much
difference, because R, G or B are already very different from W.
If this is the case, then perhaps what I should do is de-weight samples
(such as white, C, M, Y etc.) that are not near the primaries.
Graeme Gill.
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