The key that got me to understand is that our eyes have only the three types of photoreceptor cells that detect color (a.k.a. cones): Red, green, and blue. We don’t have cones that see yellow, for instance.
Red light has wavelengths in the 625-750 nanometer range, and green is 500-565nm. Yellow is between red and green at 565-590nm. The ranges that our cones detect are kind of fuzzy, and imprecise. Which means that yellow light will stimulate the red codes a little bit, and stimulate the green cones a little bit, too. Then, our brains combine the signal from the red and green cones to extrapolate that the light is actually yellow.
But that means our eyes can be easily fooled. If we mix a red light that stimulates our red cones with a green light that stimulates our green cones, our brains receive the same neural signals as if it were yellow light, and so we perceive yellow. The same holds true for all other non-RGB colors.
Mixing paints is an entirely different phenomenon, though. Red paint absorbs all colors of light except red, so the light that bounces off and reaches our eyes consists of the red wavelengths. Green paint absorbs all colors of light except green. When you mix red and green paint together, the green paint absorbs the red light, and the red paint absorbs the green light, and both of them absorb all of the other wavelengths. They absorb light imperfectly, so the result that we see is some sort of muddled brown. Mix enough paint colors together, and the resulting paint absorbs almost all wavelengths of light, so it looks black.
I guess you could think about it as where the mixing happens, whether the mixing happens out in the world, and the resulting light reaches our eyes, or whether the light reaches our eyes first, and the mixing happens there.
Also, Spectral Colours are those defined wavelength of light.
False Colours are those that are a result of our eye’s/brain’s color processing.
E.g. purple is not a spectral color: there is no purple wavelength (indigo and violet are still just blue). Blue and red are at opposing ends of the spectrum and stimulate our blue and red cones which or brain interests as purple.
The key that got me to understand is that our eyes have only the three types of photoreceptor cells that detect color (a.k.a. cones): Red, green, and blue. We don’t have cones that see yellow, for instance.
Red light has wavelengths in the 625-750 nanometer range, and green is 500-565nm. Yellow is between red and green at 565-590nm. The ranges that our cones detect are kind of fuzzy, and imprecise. Which means that yellow light will stimulate the red codes a little bit, and stimulate the green cones a little bit, too. Then, our brains combine the signal from the red and green cones to extrapolate that the light is actually yellow.
But that means our eyes can be easily fooled. If we mix a red light that stimulates our red cones with a green light that stimulates our green cones, our brains receive the same neural signals as if it were yellow light, and so we perceive yellow. The same holds true for all other non-RGB colors.
Mixing paints is an entirely different phenomenon, though. Red paint absorbs all colors of light except red, so the light that bounces off and reaches our eyes consists of the red wavelengths. Green paint absorbs all colors of light except green. When you mix red and green paint together, the green paint absorbs the red light, and the red paint absorbs the green light, and both of them absorb all of the other wavelengths. They absorb light imperfectly, so the result that we see is some sort of muddled brown. Mix enough paint colors together, and the resulting paint absorbs almost all wavelengths of light, so it looks black.
I guess you could think about it as where the mixing happens, whether the mixing happens out in the world, and the resulting light reaches our eyes, or whether the light reaches our eyes first, and the mixing happens there.
Also, Spectral Colours are those defined wavelength of light.
False Colours are those that are a result of our eye’s/brain’s color processing.
E.g. purple is not a spectral color: there is no purple wavelength (indigo and violet are still just blue). Blue and red are at opposing ends of the spectrum and stimulate our blue and red cones which or brain interests as purple.