Is it possible to conceive of another primary colour?

[zoobyshoe]

They must spend more time looking at those little paint charts than I do. Like anything else, most people can improve their color perception through practice, or just by being more interested.

This is part of my point. If people can be trained to pay attention to, and name, and remember subtle differences in color, it strongly suggests that we all do see color pretty much the same. This kind of goes against your speculation that we might be experiencing greater differences in color perception than we realize (except in the case of undiagnosed partial color-blindness).

I think if I showed you something ecru and something tan side by side, you'd have no problem seeing the difference. Becoming conversant with all the terms is a matter of constant working with them. Perception of the differences, whether you can name them or not, is already in place.

 

[BobG]

Yes and no, kind of.

Everyone has a slightly different average body temperature and their actual body temperature varies over the course of the day, or even the course of the month. But everyone's average body temperature is close enough that a funtional 'normal' body temperature can be established by just rounding up to 37 degrees celsius (the average average body temperature is closer to 36.8).

Even though a person's average body temperature may be lower than the average person, they can still sense most significant differences in their own body temperature.

As long as everyone's vision range is pretty close to the norm and their ability to distinguish colors is pretty close to the norm and colors are described fairly generically (red, yellow, green, blue), how could they tell that it doesn't quite match the 'defined' wavelength for each color.

Functionally, there's almost no difference. The differences in color perception from person to person is very subtle and there's only a few people who's range is skewed just the right amount from the norm to have 'peculiar' quirks that only become evident towards the edge of an accepted range for a given color.

And, logically, considering just about everyone's average body temperature, voice, height, weight, ability to hear (perfect pitch, for example) are all slightly different, I'd be surprised to find out every human's vision is exactly the same. (Which probably makes me slightly biased towards believing the articles that say people's color perception varies.)

 

[donnie]

Good stuff.
Consider the colour of water.