some head torches now come with multiple coloured lights,
originally it was just red for low light conditions, but you can now get them also with blue and green on the same head torch
I havent found information that explains the best use of these lights.
the green is the brightest of the colours, the blue the next brightest with the red the dimmest
i'd red green and blue were better than red to reduce night blindness, but the green is a lot brighter, its arguably too bright even for a night light in a hut...
blue isnt too bright, but in theory that can interupt or prolong your body clock letting you get to sleep...
that brings you back to.... red...
maybe i'd use blue or green when i wake up and red before going to sleep or in the middle of the night...
Yeah... first world problems... terrible arent they....