The difference between a natural lens, a replacement lens with UV absorption, and a clear replacement can be very large in daylight vs. other sources. I got UV absorbing lenses in both eyes, and during the time I had only one replacement, the difference was quite noticeable. A colleague who had one UV absorbing and one clear reported some extreme differences. I had a khaki colored parka that was mainly cotton, but synthetic knit for the collar. In daylight, I saw a slight mismatch, but he saw a strong purple cast to the collar. I wear photo gray glasses, and I can see an amber tint under artificial light and a much stronger amber tint under daylight. My natural lenses had browned to the point that I could not see the tint. -----Original Message----- From: Graeme Gill via colorsync-users <colorsync-users@lists.apple.com> Sent: Monday, July 22, 2024 5:29 PM To: ColorSync <colorsync-users@lists.apple.com> Cc: Graeme Gill <graeme2@argyllcms.com> Subject: Re: Why 2 degree observer measurements for ICC profiles? Peter Miles via colorsync-users wrote:
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?
In some numerical simulations I've done, this depends heavily on how narrow band the colors are. Make them very narrow (such as lasers) and you can expect extreme differences in perceived color (I saw of the order of 30 dE for some observer pairs). Of course a print evaluation is the least provocative situation since typical colorants used on paper have relatively mild transitions vs. wavelength. This is why reflective and transmissive media that uses typical pigments or dyes has smaller gamuts than emissive displays or interference effects filters.
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.
How different this will be in practice depends on how "bumpy" the difference in the transmission spectra of your two lenses are. A smooth difference will amount to a change in white point, but is less likely to change what you regard as a colorimetric match. More rapidly changing differences could have some effect, depending on the coincidence between those differences and the transition bands of the color stimulus. Cheers, Graeme Gill. _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/waynebretl%40cox.net This email sent to waynebretl@cox.net