While this is just a static 2d image, it looks like blue is above the screen (for me, for some others it's below, or red is above).
Thanks to comments, here some explanations https://en.wikipedia.org/wiki/Chromostereopsis
Edited: added Wikipedia link
Okay so what's going on here? This is the first time I've seen this illusion without my glasses, though it's stronger with.
I see the blue further back; the red sticks out forward to me. And I've seen that with colours on my screen and - I think - printed colours too sometimes.
Or is this something else, about the blue being a bit fuzzier or something? (In which case my own colour depth separation is something else.)
Red and blue are on opposite side of the visible spectrum.