It's Okay To Be Smart

Adding some color

Yesterday’s OK Go video about the primary colors had an incomplete explanation, and I apologize for that. I should do better. Here’s some more context, because color is confusing, and no, you weren’t lied to in kindergarten

If our eyes use red, blue and green to interpret all colors of light, then why did we learn that red, yellow and blue are the primary colors?

It has to do with additive versus subtractive color.

We know that all wavelengths of light mixed together make white light, the principle of additive color. Pink Floyd demonstrated this well.

Think about sunlight, which is a pretty even mix of a broad range of wavelengths. When light is entering our eye, additive colors are created by adding together signals from cone cells that read different wavelengths. This is how TVs and computer screens work, too.

Green + red = yellow
Green + blue = cyan (light blue)
Red + blue = magenta
Red + blue + green = white

That’s just how our biology works. But when we were in school, we played with paints. Paints are made of pigments, which follow the rules of subtractive color.

If we made a list of subtractive color mixes, it would look like this:

Yellow pigment absorbs blue—reflects red, green
Cyan absorbs red—reflects green, blue
Magenta absorbs green—reflects red, blue
Blue absorbs red, green—reflects blue
Red absorbs blue, green—reflects red
Green absorbs blue, red—reflects green

Now we can do a thought experiment, because we’re on the internet and that’s our only choice.

Paint your mind’s canvas with magenta paint. Magenta pigment reflects red and blue light, as you see in the second table. So then the red and blue light hits your eyes, mixing together to make magenta - just like in the top table!!!

Got it? Good!