scott wrote:
>> I'm talking about the correct conversion xyY to s(c)RGB and nothing else.
> 
> In that case the idea of a "source whitepoint" is meaningless - xyY 
> specifies colours exactly in absolute colour space,

The CIE calls it a device independent color space.


> there is no need for 
> a reference white, nor does one exist.

The CIE has defined D50 as reference white for the device independent 
xyz color space and e.g. every spectrophotometer including my own one is 
calibrated to D50 for exactly this reason.


An xyY colour like (0.3,0.3,10)
> specifies one unique colour exactly, no need for any additional 
> information about a white point.

There is a strong need to take the reference white and the whitepoint of 
any device dependent target color system (and e.g. RGB or CMY or YCC are 
always device dependent) into account.
You can only ignore refrence white for e.g. converting from CIE xyz to 
CIE L*a*b 'cause L*a*b is also a device independent color space.

-Ive

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