Blue light might not be disrupting your sleep pattern after all, or at least not as much as night mode does, according to new research.

That’s the word from University of Manchester scientists, who said Monday that looking at cooler-colored lights in the evening and warmer colors in the daytime “may be more beneficial to our health.” The body clock uses the dim and blue appearance of twilight to determine when to sleep, they say.

“Technologies designed to limit our evening exposure to blue light, for example by changing the screen color on mobile devices, may therefore send us mixed messages,” the university said Monday. “This is because the small changes in brightness they produce are accompanied by colors that more resemble day.”

The impact on sleep patterns is weaker when using phone displays with blue colors than it is with bright yellow colors, the researchers found by testing brightness and colors on mice.