macOS High Sierra’s Night Shift is a feature brought over from iOS. It helps you reduce the amount of blue light you're exposed to during the evening by shifting the display of a Mac to a more yellow tone.
Blue wavelengths—which are beneficial during daylight hours because they boost attention, reaction times, and mood—seem to be disruptive at night. The proliferation of electronics with screens, as well as energy-efficient lighting, is increasing our exposure to blue wavelengths, especially after sundown and may affect sleeping patterns.
Apple hasn't made it as simple as possible to implement Night Shift in macOS, but here’s how you do it:
- Open the System Preferences app.
- Click Displays.
- Select Night Shift.
You can turn Night Shift on or off. Set it to come on from sunset to sunrise — or you can use the Customize options to implement it for the hours of your choosing.
You can also adjust the color temperature via a slider. Warmer settings may affect the appearance of some onscreen motion.