Kunilou, it seems to me that paul’smars’ is more complicated than that.
Paul’smars’, I think you’re getting at something like the following:
Scientist X is studying two subjects: A & B.
Person A’s brain interprets the visual information yielded from a given prism in approximately the following chromatic order (as defined by X): red, orange, yellow, green, blue, purple
Person B’s brain interprets the same visual information from the same given prism in approximately the following chromatic order (as defined by X): green, blue, purple, red, orange, yellow
So if Person A could somehow borrow Person B’s brain, Person A would see purple bananas, green stop signs, a pale-orange-colored sky, buttery-yellow lavender flowers, etc. Yet Person B, living with a “distorted” sense of color, is none the wiser.
…
Now then, I must bowdlerize a bit:
One simple, initial test that could be used to flesh these perceptions out would be for Scientist X to ask both A & B about the relative darkness or lightness of the colors of certain objects (probably color swatches or chips similar to those used in printing or fashion). For example, yellow objects would appear darker to B than blue objects (given equal amounts of saturation and brightness).