Depends on the typical and current conditions of the viewer--however few people realize it. Those that do use f.lux or one of the others.
For example, if the viewer sits in an office under 50 florescent lights, dark on light is best (e.g. Excel-jockies). This viewer "can't imagine any other way!" I often wonder how these people survived before Windows.
If instead they are a digital artist in dim lighting (for better color accuracy) then bright white pages will be blinding, "my eyes are bleeding". Ditto the late-night hacker.
Since I'm online day and night I make judicious use of the negative plugin in compiz (Super+N) and turn down screen brightness at night. When on Windows I use f.lux.
For example, if the viewer sits in an office under 50 florescent lights, dark on light is best (e.g. Excel-jockies). This viewer "can't imagine any other way!" I often wonder how these people survived before Windows.
If instead they are a digital artist in dim lighting (for better color accuracy) then bright white pages will be blinding, "my eyes are bleeding". Ditto the late-night hacker.
Since I'm online day and night I make judicious use of the negative plugin in compiz (Super+N) and turn down screen brightness at night. When on Windows I use f.lux.
For the browser specifically, the invert-lightness bookmarklet is also helpful when a lot of images are involved: https://www.squarefree.com/bookmarklets/color.html