You know, this isn't just any "easy answer" for it really depends upon your ability to recognize, discern and comprehend in a given spectrum of color in low-light conditions without losing Visual Acuity.
In having to defend a fellow former employee from termination because they were "Color Blind" puts this in perspective for me to even have anything to say about it.
This also can extend into the ability to maintain Night Vision to even function at night while driving or other activity requiring the use of adverted and low-light conditions which affect our vision.
To be honest, use a "soft color" one that can be washed into the rest of spectrum with even diffusion of the spectral colors - using all of the colors, then to focus on one particular color and find out that it too - makes things look fuzzy and are hard to discern because of one wavelength emission versus several scattered across a broader portion lie a tint would provide..
Incandescent works best but not the most efficient but can be filtered for a broad range of color thru tints.
- Unlike with LED - which emit strongly in one color - is just in one narrow band of emission not in any others close by unless you use a multi-color LED with shading (grey/dimming) available to wash out predominate coloring that can make it look blurred - either by astigmatism, refraction or even color blindness.
Just understand the light spectrum uses combinations of various ranges of emission energy, or wavelengths of light - to combine and form the hues, tins shades and intensities and subtleties' or nuances light can give us.
Because of the refractive index our eyes - the lens, cornea even the vitreous humor - affects the passage of light into the retina and if some light as a specific wavelength or range of the color spectrum doesn't land correctly onto the retina - the images look distorted and out of focus for the very reason - change the color or wavelength used, changes how the eye focuses that energy easily enough to be discerned.
Maybe this is more than you needed to know, but if you are ever in a situation where you are using equipment in low-light conditions - this acuity and discernment in which colors to use and to be able to use the equipment in such conditions becomes a very important issue.