Yellow-to-orange seems to be the most efficacious color range.
As research mounts on the possible health-effects of “blue light,” several recent studies have also reported the negative impact of computers, TVs, video games and the like on sleep, particularly when used near bedtime. A group of Swiss scientists has published a study that suggests a simple remedy: orange-tinted lenses. Others, in the lab and on the street, have reported similar sleep-inducing results from yellow and amber lenses. Several optical companies are now manufacturing lenses in these colors, and lenses with other “blue-blocking” properties.
Read more at International Business Times