[mikece]

Sounds like it should be trivial to build a website -- a future Show HN? -- to make the whole screen the correct color for a specific interval of time, fading in an out at the start/finish. The only thing the user might have to do it turn up the screen brightness first.

[the8472]

Computer monitors do not work like that. They emit a mix of 3 fixed spectra. You cannot shift the red to an even longer wavelength. At least not without adding some physical filters on top that only let through the long tail (which is fairly inefficient). At that point you might as well buy specialized LEDs.