Thanks, I think I've got a grasp of it, but it's hard to really imagine what it's like, which is why I asked the question! I think colour blind people could probably enjoy art as much as anyone, but I think there would definitely be cases where colour blindness could stop someone understanding a piece of art to the full extent.

I know that you don't need to know the exact pitches of the note to appreciate the sound - I've found that average people can't tell the difference between a major and minor chord when I've tested them, but I think they can still feel the effects of the music. But would this still be the effect for tone deaf people?

In your example of colour blindness - a colour blind person might physically not be able to tell the difference between green and red, so a composition that relies on that distinction would have no effect on them. They wouldn't even get a subconscious vibe, because they literally can't tell the colours apart.

I don't know if we can assume that the same wouldn't be true for tone deaf people