R help - Jun 2013 - grDevices::convertColor XYZ space is it really xyY?

grDevices::convertColor has arguments 'from' and 'to' which can
take on value 'XYZ'.  Can someone confirm that 'XYZ' is the same
as the CIE chromaticity coordinates that are also sometimes refered to as
'xyY' in the literature?  Or are these the CIE tristimulus values?  It
looks to me like the first case is true, but I would appreciate hearing from one
of the people in the know.  Thanks, Bryan

On 12/06/2013 2:45 PM, Bryan Hanson wrote:
> grDevices::convertColor has arguments 'from' and 'to' which
can take on value 'XYZ'.  Can someone confirm that 'XYZ' is the
same as the CIE chromaticity coordinates that are also sometimes refered to as
'xyY' in the literature?  Or are these the CIE tristimulus values?  It
looks to me like the first case is true, but I would appreciate hearing from one
of the people in the know.  Thanks, Bryan
According to the referenced web page from ?convertColor (i.e. 
http://www.brucelindbloom.com/), XYZ is not xyY, though the conversion 
looks pretty simple.

Duncan Murdoch

Bryan Hanson <hanson <at> depauw.edu> writes:
> 
> grDevices::convertColor has arguments 'from' and 'to' which
can
take on value 'XYZ'.  Can 
someone confirm
> that 'XYZ' is the same as the CIE chromaticity coordinates 
 are also sometimes refered to 
as 'xyY' in
> the literature?  Or are these the CIE tristimulus values?  
It looks to me like the first case is 
true, but I
> would appreciate hearing from one of the people in 
 know.  Thanks, Bryan
> 
> 
I.'d look at the code or put in some known data to test it, 
but XYZ are tristimulus values and xyY are chromaticity
coordinated and the luminance which is the Y tristimulus
value for the CIE 1931 standard observer.

Ken