I've been comparing how TIFF V6.0 and the (proposed) ISO Image
Interchange Facility (IIF) [draft as of 27 March 1992] specify the CIE
chromaticity and luminance values for the white point and each of the
TIFF only specifies the CIE x and y chromaticity values for the
white point and the primaries, whereas the IIF spec specifies x,y and
Y, as well as the CIE standard observer (2 degrees 1931 or 10 degrees
Since the TIFF spec says that the chromaticity values apply to the
1931 CIE xy chromaticity diagram, there's no ambiguity there [although
I do have a question about how the specification of the observer
effects the identification of each of the primaries and the white
point, and consequently, the 'color' of any pixel].
My most pressing question is this: since TIFF does not specify
what the Y value is for either the white point (though I assume this
can be assumed to be 1.0, yes?) or any of the primaries, what should
any reader of TIFF 6.0 files assume the Y value to be (for the white
point and the primaries)? *CAN* a reader even assume a value for Y for
the white point and the primaries?
I'd appreciate e-mail replies [or e-mail copies of posted replies]
since I don't read this group very often. Thanx in advance.