I like to read in bed at night, next to my wife, before I go to sleep. And I find that a red light is really advantageous, for three reasons:
1) The printed type stands out from the page very strongly, at much lower light levels than with other colored lights. Perhaps something about the ink absorption? And no glare from the white page? In any case, the black-on-white effect is very strong and striking, even when the light is dim.
2) The red light makes it easier for my wife to sleep.
3) The red light also makes it easier for me to relax at the end of the day. Studies show that blue light (e.g. from computer screens) suppresses melatonin, and so make it harder to fall asleep. Red light does not suppress melatonin, and so allows your body to relax and keep its normal circadian rhythm.
The other advantage of this set-up is that a red LED running at a fairly low level (a lumen or less) lasts for a long, long time, even on coin-cells.
So I generally use two kinds of headlights for reading at night:
1) the Petzl e-lite, which I write about in a different post on this same forum;
2) A Photon key-chain light in Red, clipped to my reading-glasses with their plastic spring-clip. It is so light that it does not affect the balance of the reading-glasses frame. The light is fully dimmable for different light needs. And I get *months* of use out of a single 2032 coin cell, i.e. 50 hours or more.
Now: if you want to read books that have color photos, then this will not work. If you want to *avoid* getting sleepy while you are reading, then the lack of melatonin-suppression is not an advantage. If you want to read books and also repair small engines at the same time, then you will want brighter light.
But if you want to read in bed for a few hours before drifting off to sleep, then I strongly recommend the Photon or the E-lite (though that one is not dimmable).
