Thanks Graeme, and everyone for your responses. A lot of food for thought. Reflik I had a looked at the “Individual Colorimetric Observer Model” paper, however I don’t have a training in color science to fully grasp the significance of what I am reading. Is there a way of qualifying what sort of size colour differences these observer variations are causing in the normally sighted population? If they were all looking at the same objects in a viewing booth, what sort of magnitude of potential colour differences would they be seeing? FYI: A few years ago I had a lens replaced in one of my eyes and so I now have two quite different ‘observers’ when it comes to assessing colour. Thanks Peter Miles From: Graeme Gill via colorsync-users <colorsync-users@lists.apple.com> Date: Friday, 19 July 2024 at 8:49 PM To: ColorSync <colorsync-users@lists.apple.com> Subject: Re: Why 2 degree observer measurements for ICC profiles? 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.