> Pure black on white has been discussed many times. While it satisfies min contrast requirements, it feels unnatural, and again, hard to read, causing eye strain…

I completely disagree with this. Consider the failure modes of erring in either direction:

- Too much contrast? Reduce screen brightness. (This has the beneficial side effect of increasing battery life on mobile devices.)

- Too little contrast? Uhh… squint more, or try to find software that lets you override the designer's intent.

Most people aren't using professional screens in low lighting, and not everyone has young eyes. Lower contrast can be a deal-breaker for these people. Even for those with perfect vision, low contrast can be incredibly annoying. It's so frustrating to view a screen in direct sunlight and be unable to see content because a designer didn't want to cause eye strain.

A side note: Amusingly, the first thing I did when looking at your second source (http://ianstormtaylor.com/design-tip-never-use-black/) was use my reader mode extension. I disliked the off-black sans-serif font.