Peter Miles via colorsync-users wrote:
So why do ICC profiles, for print production, still use 2degree observer measurements instead of 10 degree observer measurements?
A standard often has a momentum of its own. But in the case of color in media that is looked at in detail (such as images), 2 degree is appropriate. AFAIK, one of the reasons that the 10 degree observer is often recommended is that it was created with more observers and in a more refined way, and is technically a bit more accurate. In subsequent experience it has often turned out that the 10 degree standard matches people more accurately than the earlier 2 degree observer, even though it is not the appropriate viewing angle. Note that there are many subsequent more refined standards or proposed standards such as the 2012 2 and 10 degree observers. These are not in widespread use though, whereas every graphic arts instrument will return 1931 2 degree values. And of course there is nothing to stop you making ICC profiles using any observer you like :-) They may not be technically interchangeable with profiles using the 1931 2 degree observer, but that matters less in practice, and not at all if all the profiles you use use the same observer. Cheers, Graeme Gill.