Yuck! Funny though I wrote a program for making red-cyan anaglyph stereograms using TkInter/Python. Stereograms work best when you can put important objects at the plane of the paper/screen and this is done by sliding the left and right images relative to each other.

Tk has no color management, unlike newer frameworks, which was good in this case because I asked for (255,0,0) and got (255,0,0). When I exported to JPEG and views on a web browser though I got something like (186, 16, 16) because on my wide gamut monitor the native primaries are more saturated than sRGB primaries so some white gets blended in to make them less saturated. Turns out in Windows, screenshots are in the color space of your monitor! It’s something you’d never notice unless you made stereograms because that little bit of green and blue goes to the wrong eye.