RU.08 said:
Right, I didn’t disagree but can we both agree you’re talking about photoreceptors in the eye and the neurological links in the brain? And the S/M/L cones in particular? All cones are sensitive to all colours, which is probably why we can’t see the same dynamic range that a 16-bit digital colour sensor can which is receptive to only one type of colour. Anyway most variating in how we percieve colour is due to people having a different ratio of L-type to M-type cones in the eye, which is believed to vary greatly, but I don’t see how it would affect someone with 20/20 vision to match two colour sources accurately with the right tools and methods.

It affects someone in the sense, that they won’t be able to distinguish between two shades of a color. For example one person’s eyes will be less sensitive to red, such that they percieve one shade of red, whereas to someone else it’s a different shade. That other person might have eyes, that are less sensitive to blue, and therefore not notice the subtle differences between two different blues. It’s nothing to do with color blindness, it’s just that our eyes, like any sensor, have a lower detection limit, which differs from person to person.

I think it would actually be an interesting experiment to let 10 different people grade a scan, while viewing the same print.