(Photo : Unsplash)

If you think your phone's "night mode" screen feature helps with sleep by shifting to warmer tones late at night, think again.

In an article by Business Insider, a new study conducted by the University of Manchester led by Dr. Tim Brown, and published in Current Biology, suggests that it is more natural to look at blue light in the evening and warm light during the day. According to the study, it is because natural light is actually bluer during twilight.

It is commonly known that blue light is more disruptive to people's circadian rhythm than warm colors. In a report by The Guardian, it has led companies manufacturing mobile devices to include night mode screen among the phones' recent features. For instance, iPhone and iPad automatically shift displays to an orange-yellow tint late at night. This notion was strengthened by past studies claiming that blue light prevents the body from producing of melatonin a hormone that influences sleep.

Furthermore, Brown said the idea of limiting blue light from screens started about 20 years ago with the discovery of melanopsin - a light-sensitive protein found in the eye that plays a crucial role in regulating the body clock.

"The melanopsin system is fundamentally there to detect brightness," says Brown. Because melanopsin was better at detecting short-wavelength photons, he says, it was thought it was biased in favor of blue light. In fact, it is the retina's cone cells that determine color. "The cone system also plays a role, and they're doing the opposite of what most people thought," says Brown.

"We show the common view that blue light has the strongest effect on the clock is misguided; in fact, the blue colors that are associated with twilight have a weaker effect than white or yellow light of equivalent brightness," he added.

The team of researchers conducted a test on mice and used specially designed lighting in order to test how different wavelengths affected sleep patterns. They found out that blue light proved to be less disruptive to mice's sleep than yellow light of the same brightness.

According to the study, it is more important to consider brightness levels than color when it comes to stimulating the body clock. However, when both blue and yellow lights are equally dimed, blue is more relaxing than yellow.

The study, however, was only conducted mice, and it may not produce similar results when conducted to humans. "We think there is good reason to believe it's also true in humans," says Dr Brown.

According to the researchers, further studies are necessary to fully understand how human sleep patterns are affected by different light wavelengths.

"Our findings suggest that using dim, cooler, lights in the evening and bright warmer lights in the day may be more beneficial," Brown said, seemingly reaffirming the common belief that lower brightness is less disruptive to sleep.

In a simpler sense the night mode screen feature of your phone is contradictory to the fact that daylight is yellow, twilight is blue, and sunrise and sunset naturally tell the body what time it is.