Night Shift is a built in software feature of

iOS iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple Inc. exclusively for its hardware. It is the operating system that powers many of the company's mobile devices, including the iPhone; the term also include ...

and

macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lapt ...

. It was introduced in 2016-2017 into

in iOS 9.3 and into

in macOS Sierra 10.12.4. The feature changes the

color temperature Color temperature is the color of light emitted by an idealized opaque, non-reflective body at a particular temperature measured in kelvins. The color temperature scale is used to categorize the color of light emitted by other light sources ...

of the display towards the warmer part of the

color spectrum The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called ''visible light'' or simply light. A typical human eye will respond to wavel ...

that reduces some of the blue light from the screen.

Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, ' ...

claims that the feature may help users have a better night's sleep by filtering blue wavelengths from the display, which suppress melatonin biosynthesis. The feature is similar to the functionality f.lux provides.

Effectiveness

Changing the color temperature of the display from blue towards yellow (without dimming the screen) was shown to have no effect on sleep outcomes (sleep latency, duration, efficiency and wake after sleep onset) in a 2021 study on 167 college undergraduates and to be insufficient for preventing the impact on melatonin suppression. In mice, yellow colors disrupted the mouse body clock more than equally bright blue colors.

Compatibility

The Night Shift feature is compatible with all

64-bit In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit CPUs and ALUs are those that are based on processor registers, address buses, or data buses of that size. A compu ...

iOS devices running on iOS 9.3 and above and Macs from 2012 and later running on macOS Sierra 10.12.4 and above.

Functionality

The feature can be turned on in Settings (in iOS) and in System Preferences (in macOS) and can be toggled on or off manually in the Notification Center (in macOS) or in the Control Center (in iOS). The feature can be enabled or disabled with

Siri Siri ( ) is a virtual assistant that is part of Apple Inc.'s iOS, iPadOS, watchOS, macOS, tvOS, and audioOS operating systems. It uses voice queries, gesture based control, focus-tracking and a natural-language user interface to answer qu ...

in iOS and macOS. The feature can set so it is enabled at sunset and turn off at sunrise (the default) or turned on and off on a custom schedule. The feature when set to enable at sunset and disable at sunrise relies on the user's approximate location to determine the time of sunset and sunrise. The user can also customize the intensity of Night Shift in Settings (iOS) or System Preferences (macOS).

References

{{macOS IOS MacOS

Effectiveness

Compatibility

Functionality

See also

References