Am 29.11.2016 um 00:33 schrieb Mike Horvath:
> On 11/28/2016 6:05 PM, clipka wrote:
>>> I thought there was some tapering as the Y increases? This image
>>> suggests that is the case.
>>>
>>>
http://www.math.ubc.ca/~cass/courses/m309-03a/m309-projects/bajwa/images/cie_3d.gif
>>>
>>
>> That's not the limit of the xyY space.
>>
>> That's the theoretical limit of _reflective_ colours illuminated by
>> standard illuminant C, plotted in xyY space.
>>
> 
> Yes, that is fine. Not sure whether to use C or D65, though.
> 
> https://en.wikipedia.org/wiki/Illuminant_D65
> 
> These images on Wikipedia use D65, so I may just stick with that.
> 
> https://en.wikipedia.org/wiki/File:Cie_Chart_with_sRGB_gamut_by_spigget.png
> https://en.wikipedia.org/wiki/File:CIE1931xy_gamut_comparison.svg
> https://en.wikipedia.org/wiki/File:Lab_color_space.png (I think)

The first two /show/ the D65 whitepoint (or, more precisely, its xy
coordinates), but other than that they're entirely independent of any
whitepoint. The first image even shows various other whitepoints.

As for the third image, I can't see where you got the idea that it has
anything to do with any whitepoint (except maybe for the fact that the
sRGB colour space, of which a few slices are shown, is defined such that
its "upper right" corner coincides with D65).

(Of course the image files themselves may also happen to be using a
colour encoding scheme that uses D65 as its nominal whitepoint, but I
don't think that's relevant in this context.)

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