It’s a lot more subtle. I have a hard time with certain types of purple versus blue, and can’t perceive the differences in brightnesses of greens. A favourite watercolour by kids’ artist Marie-Louise Gay has a sudden transition between a purple tree trunk and a green tree branch that I never noticed. Same tonal qualites and jsut the right frequencies that it never hit me. But now that it’s been pointed out to me, I can see it. Kinda.

It sounds like your dad has it worse. But it might be even worse than ever because of aging!

If you can stand the lab-language (hey I studied this sort of thing, so it’s second nature) there’s a good site here: http://www.ergogero.com/FAQ/Part4/cfaqPart4.html. Short version: there are seven types of colour blindness, and then there’s aging on top of it! They say that designers often make the mistake of worrying about the 1% of those heavily colour-blind while forgetting the elderly, who almost all have colour perception issue due to the darkening and yellowing of the lens and the cornea.

I think Ronnie’s less red sensitive. For example: he has a purple and a blue puffer he only uses when he’s sick. There’s a big difference between them: the purple puffer has steroids in it, he can only take it twice a day, and he needs to take it for a prescribed amount of time. He can use the blue one more liberally. We asked him to get the purple puffer, and he picked up the blue one. Somewhat of a concern now, because he can self-medicate. I had to write the word “purple” on the purple one. So this is what you’re talking about.. colour blindness is subtle. It’s as though he can’t see enought red in the purple to be able to distinguish it from blue. I think it’s the same with orange/red for him. I haven’t noticed any trouble with greens.

I’m learning more and more about it. It’s facinating, actually.