f.lux (pronounced "flux") is a

cross-platform In computing, cross-platform software (also called multi-platform software, platform-agnostic software, or platform-independent software) is computer software that is designed to work in several computing platforms. Some cross-platform softwar ...

computer program A computer program is a sequence or set of instructions in a programming language for a computer to execute. Computer programs are one component of software, which also includes documentation and other intangible components. A computer prog ...

that adjusts a display's

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 ...

according to location and time of day, offering functional respite for the eyes. The program is designed to reduce

eye strain Eye strain, also known as asthenopia (from Greek ''a-sthen-opia'', grc, ἀσθενωπία, ), is a common eye condition that manifests through non-specific symptoms such as fatigue, pain in or around the eyes, blurred vision, headache, and o ...

during night-time use, helping to reduce disruption of sleep patterns.

Functionality

On installation, the user can choose a location based on

geographic coordinates The geographic coordinate system (GCS) is a spherical or ellipsoidal coordinate system for measuring and communicating positions directly on the Earth as latitude and longitude. It is the simplest, oldest and most widely used of the various ...

, a ZIP code, or the name of a location. The program then automatically calibrates the device display's

to account for time of day, based on

sunrise Sunrise (or sunup) is the moment when the upper rim of the Sun appears on the horizon in the morning. The term can also refer to the entire process of the solar disk crossing the horizon and its accompanying atmospheric effects. Terminology A ...

and

sunset Sunset, also known as sundown, is the daily disappearance of the Sun below the horizon due to Earth's rotation. As viewed from everywhere on Earth (except the North and South poles), the equinox Sun sets due west at the moment of both the spring ...

at the chosen location. At sunset, it will gradually change the color temperature to a warmer color and restore the original color at sunrise. f.lux offers a variety of color profiles and pre-defined temperature values, modifying program behaviour for specific programs or activities; including a mode for film watching, decreasing red tinge (for 2.5 hours), and a darkroom mode that does not affect night-adapted vision. 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 An LED lamp or LED light bulb is an electric light that produces light using light-emitting diodes (LEDs). LED lamps are significantly more energy-efficient than equivalent incandescent lamps and can be significantly more efficient than ...

, so that the color temperature of house lights follows f.lux's settings.

Platforms

The program is available for

Microsoft Windows Windows is a group of several Proprietary software, proprietary graphical user interface, graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, W ...

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 (computer), Mac computers. Within the market of ...

and

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, whic ...

(except for Ubuntu 18.04 LTS). It is also available for

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 ...

iOS devices, although it requires the device to be jailbroken. Apple has not allowed the application in its

App Store An App Store (or app marketplace) is a type of digital distribution platform for computer software called applications, often in a mobile context. Apps provide a specific set of functions which, by definition, do not include the running of the c ...

due to its use of restricted developer tools. The developer briefly hosted an

Xcode Xcode is Apple's integrated development environment (IDE) for macOS, used to develop software for macOS, iOS, iPadOS, watchOS, and tvOS. It was initially released in late 2003; the latest stable release is version 14.2, released on December 13, ...

project on

GitHub GitHub, Inc. () is an Internet hosting service for software development and version control using Git. It provides the distributed version control of Git plus access control, bug tracking, software feature requests, task management, conti ...

, allowing

iOS 9 iOS 9 is the ninth major release of the iOS mobile operating system developed by Apple Inc., being the successor to iOS 8. It was announced at the company's Worldwide Developers Conference on June 8, 2015, and was released on September 16, 20 ...

users to

sideload Sideloading describes the process of transferring files between two local devices, in particular between a personal computer and a mobile device such as a mobile phone, smartphone, PDA, tablet, portable media player or e-reader. Sideloading ty ...

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 called upon Apple to provide developer tools and to allow their application into the App Store. A preview version for Google's Android system is available.

Efficacy

Reducing exposure to bright (1000

lux The lux (symbol: lx) is the unit of illuminance, or luminous flux per unit area, in the International System of Units (SI). It is equal to one lumen per square metre. In photometry, this is used as a measure of the intensity, as perceived by th ...

) blue lights at night time was linked to increased

melatonin Melatonin is a natural product found in plants and animals. It is primarily known in animals as a hormone released by the pineal gland in the brain at night, and has long been associated with control of the sleep–wake cycle. In vertebrate ...

secretion in a 1996 study but a 2018 study showed that changing the spectral composition of self-luminous displays without changing their brightness settings may be insufficient for preventing impacts on melatonin suppression. 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. Although the developer provides a list of relevant research on their website, the program itself has not been scientifically tested to determine its efficacy, and the equivalent Apple program, Night Shift, 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. f.lux has been widely and positively reviewed by technology journalists, bloggers, and users.

References

External links

* {{Official website, https://justgetflux.com
The Benefits of Avoiding Blue Light Before Bedtime
how filtering out blue light from screens improves sleep quality. 2009 software Utilities for Windows Utilities for macOS Utilities for Linux IOS software Usability Sleep Proprietary cross-platform software

Functionality

Platforms

Efficacy

See also

References

External links