Now, if I draw two tiny spots with red and blue paint on paper and they are so close (but they do not cover each other) to each other that human eyes cannot identify there are two spots. To the color that our eyes can perceive, I come across two statement on the web.
The first is the subtractive principle. It says that, in that small area, the red paint absorbs light other than red and the blue paint absorbs light other than blue. As a result, Longwave and Shortwave are absorbed and there is almost no light come into our eyes and we see black.
The second says in that small area, red lights are reflected from red paint spot and blue lights are reflected from blue paint spot. Thus these two lights, shoulder to shoulder, come into our eyes. These two lights are so close to each other and almost one light for our eyes’ ability. So when the light come into our eyes, it is a mixture of red and blue lights, just magenta.
I have made some experiments with my scanner and printer which told me the result of the mixture is black but not magenta. But I really do not know how to refute the second statement, so I come here for help.
Your helpful answers and comments inspired me that the answer is purple and the first statement is wrong because Subtractive color only happens when two inks overlaps. Here is a image I made to show the result (Interpolation is used to compress it, so zoom in will not show you the original pixels).