A natural or daylight-colored light bulb may serve best for reading. This color is found in the light bulb color range, or temperature, between 5,000 and 6,500 Kelvin.
Lights that are whiter in color range from about 3,500 to 4,100 Kelvin while bluer white lights go from 5,000 to 6,500 Kelvin. Natural or daylight colors fall in this bluish white light range.
Possibly more important than the color of the light is its brightness. The older a person gets, the more light is needed for reading. Too much light can be just as bad as too little light, however, so using a shaded lamp is recommended.
Eye discomfort is typically a reliable indicator of bad lighting. Feelings of fatigue, a headache or squinting may suggest the need to try a different light.