Continuing on color mixing I brought up yesterday, the key factor is the purity of the color. If we have very pure blue and very pure yellow, then we will get black. However, none of colors we have are very pure. All blues and yellows we get have green in it. When they are mixed together, the blue and yellow cancel out and green light gets reflected. So we see green. The term “purity” here is vague. To be more precise I should use “spectral bandwidth”. The nearer the bandwidth is, the purer the color is. In my optics lab, I have something called “”. The blue filter allows narrow band blue light goes through, and transmits narrow band yellow. When I stack a blue filter on top of a yellow filter, I see no light goes through, or I can say I see black.
I don’t want to be too left-brain-ish. Let’s talk about painting. The painting I post today emphasizes on the subtlety of the grays. I used to get my grays by testing randomly. After I did mystudy, I have gained more sensitivity on grays, and I can obtain my grays more systematically. I like David Leffel’s paintings. He is the expert of grays.