A light source (1), which has a hollow body (2) closed in a gas-tight manner, which is coated on at least one inner side with a phosphor and is filled with gaseous tritium and emits colored light, the hollow body (2) being arranged in a housing (3) of the light source (1), the light source (1) having at least one body (4) of a colored material which annularly encircles a longitudinal center axis of the light source (1) and the color of which is different from black in daylight, the annularly encircling body (4) being arranged at least on a terminal end region of the housing (3) or at least between the terminal end region of the housing (3) and a light-emitting end face of the hollow body (2).