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>> Do you want to preserve...
>> ...the in-gamut colours?
>> ...the relationship between colours?
>> ...colour saturation?
>>
>> Colour space conversion is a complicated subject.
>
> Well, at this stage I'd like to know how to do all three.
Well if you only want to preserve the in-gamut colours then obviously you
only need to tinker with the out-of-gamut ones. For these colours I would
tempted to move the colour in the xy plane towards the white point until it
became in-gamut. Of course here you lose any "difference" perception
between in-gamut and out-gamut colours with similar hues.
If you want to preserve the relationship, then it gets harder because
colours in the Yxy or sRGB spaces are not spaced evenly for human perception
of "difference". If you want to do it properly, convert your Yxy data into
CIELAB or similar, I'd then choose three new primaries (not the sRGB
primaries) that allow all your colour points to be represented as positive
combinations of the primaries. Of course here no colours will be properly
displayed, but the relationships should be preserved.
You could also do a combination of the above two, whereby if a colour is
within say the central 50% of sRGB you map it exactly, but then further out
the colours get compressed to fit in the sRGB space, but still maintaining
some sort of difference. I think I saw some display processor from Philips
once that did this.
> However, I am running into additional problems. I am converting the 1929
> Munsell data set (http://www.cis.rit.edu/mcsl/online/munsell.php), and
> *not a single one* of the colors lies completely within the SRGB gamut.
Just by looking at the numbers, the first one is xy=0.3532,0.2957 with a
brightness of 3.126 cd/m2, that surely is within the sRGB space?
> You can test this by using the color converter found here:
>
> http://www.brucelindbloom.com/index.html?ColorCalculator.html
The first one comes out as RGB=(2.0,1.5,2.0) (rounded), seems to be within
sRGB to me!
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