Why were old 3D glasses almost always red and blue (and not, say, green and orange)?

Question

I know how old 3D glasses work, but I want to know why they were blue and red rather than two other colors opposite on the color wheel. My guess is that red and blue cellophane or inks were cheaper when the technology/technique was developed, but that’s only a guess. (I know how 3D glasses work and only want to know why those particular colors were popular or nearly universal.)

In: Technology

Answer 1

The red and green cheat the RGB that you’re seeing by excentuating those two and not blue. Something like that.