White and black are perfectly reasonable terms - I think most here understand the threshold at which grey becomes either black or white for general discussion.
Are you sure? Consider the attached image which I concocted in Photoshop. The grey text looks sort of whitish to me, and certainly whiter than the grey background surrounding the black square. But actually the text isn't whiter than the grey background. Both the text and the outer grey background have the same RGB values of 150,150,150, which I would describe as slightly paler than a medium grey.
Overall, reducing the contrast between the text, the background and the ambient light levels. The key here is ambient light levels. If you're reading in a darkened room at night, then a black background is usually very good, so long as the text isn't too bright, but in a lit office, for example, as I've demonstrated the contrast between the screen average and the ambient light is greater and that is likely to cause more strain.
No argument here. I admit there are a number of contributing factors to eye strain.
To answer your question, I wouldn't use a 400cdm^2 monitor - no matter what, I'd turn it down (calibration is not the point). I *might* decide it was useful if I was trying to see something in bright sunshine I suppose, but more likely I'd try to shade the monitor and turn it down. In other words, I find that level of brightness too contrasted to any reasonable ambient light level I'm likely to encounter in normal events.
As I already mentioned, you're very sensible
. But what about others? There are billions of people in the world, many getting a computer for the first time, and many who do not have much clue after using a computer for many years.
I'm talking about average environments in which people work and have reasonable lighting levels (200lx to 400lx).
Can you provide some statistics on world-wide average environments involving computer monitors? I get the impression you might think the world is a more reasonable and well-organised place than it actually is.