A color blind person does not perceive colors dimmer or lighter, but perceives them wrong. So for example, Van Gogh would see a wheat field and pick a color that matched the wheat to paint it, according to what he saw. Turns out that this color would be orange, because to him orange and wheat both looked the same.

As a color blind myself, I see absolutely no difference between the original and the modified images. They are 100% identical to me. So I already see them as Van Gogh did. But if you can see a difference then this proves that this experiment works.