Catoosa, Georgia. (March 12, 2025): In this photo by Sergeant Allison Gilstrap, Staff Sergeant Gregory Smith uses a red light to illuminate navigation points during a night land navigation exercise. Of all the colors in the rainbow, why does the military insist on using red lights?

The reason is twofold; to be able to see, and to not be seen.

Red light is less disruptive to the eye's ability to see in the dark compared to other colors. The eyes have two types of receptors, called rods and cones, which allow us to see colors in low light conditions. In near darkness, the eyes use the rods on the outer edges of the retina that are most sensitive to light to distinguish black and white. Because red has a longer wavelength than brighter colors like blue or green, it allows a person to see without compromising their night vision.