Question

What color combination has the highest readability

Answer 1

White background simple and classic black text on a white background provides the highest readability ratio blues and grays also provides the right contrast and thus work well on white background

Answer 2

This is different. But I will answer it.

First, you want to use light easy colors. Such as white background and colored text. But however, black background with colored text will work as well. This is only if you do not have to much text to display.