Developer(s) Flux Software LLC | Development status Active | |
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Original author(s) Initial release February 2009; 8 years ago (2009-02) Stable release Windows: v3.12
macOS: build 37.2
Linux: n/a
iOS: 0.9986 Operating system | ||
f.lux is a cross-platform computer program that adjusts a display's color temperature according to location and time of day. The program was designed to reduce eye strain during night-time use and reduce disruption of sleep patterns.
Contents
Compatibility
The program is available for Microsoft Windows, macOS and Linux. It is also available for iOS devices, although it requires the device to be jailbroken. Apple has not allowed the application in its App Store, due to its use of restricted developer tools. The developer briefly hosted an Xcode project on GitHub, allowing iOS 9 users to sideload the application onto their devices, but retracted it at the request of Apple. Following Apple's announcement of a similar function, called Night Shift, in iOS 9.3, the developer has called upon Apple to provide developer tools and to allow their application into the App Store. A preview version for Android is available.
Functionality
Upon installation, the user can choose a location based on geographic coordinates, a ZIP code or the name of a location. The program then automatically calibrates the device display's color temperature to the time of the day, based on sunrise and sunset at the chosen location. At sunset, it will gradually change the color temperature to a warmer color and restore the original color at sunrise.
The user can choose from a variety of color profiles and pre-defined temperature values. They can also modify the behavior of the program for specific programs or activities, including a mode for watching films which decreases the red tinge for 2.5 hours, and a darkroom mode that does not affect night-adapted vision. The times can be inverted on f.lux for PC to provide warm lighting during the daytime (for people who work at night). The program can control Philips Hue LED lighting, so that the color temperature of house lights follows f.lux's settings.
Efficacy
f.lux proponents hypothesize that altering the color temperature of a display to reduce the prominence of white–blue light at night will improve the effectiveness of sleep. Reducing exposure to blue light at night time has been linked to increased melatonin secretion. Although the developer provides a list of relevant research on their website, the program itself has not been scientifically tested to determine its efficacy. In spite of this, f.lux has been widely and positively reviewed by technology journalists, bloggers, and users.