(31463 ratings)

Appears in 25 channels

  • Downloads:
    500,000 - 1,000,000
  • Last update
    Feb 26, 2014

Twilight Reviews

  • Jamie Davies

    Jamie Davies

    Reviewed in Long Lasting Apps & Games

    That harsh blue light straining your eyes at night? Make your phone warmer & more comfortable to look at with Twilight. Automatically changes intensity depending on your local time. Headaches & sore eyes will be a thing of the past.

  • Nicolas Epinette

    Nicolas Epinette

    Reviewed in Top Apps Android

    Health & Fitness

  • Debanka Chanda

    Debanka Chanda

    Reviewed in TT&T(Try,test and tell)

    I have been using it since a while theory, its another screen filter app.But it filters out the blue light,and if you get a reddish hues in your screen.the blue light is said to cause strain to eye, leading to irregular sleeping .I am not sure of this theory, but ever since I got used to the reddish filter, I am using it every evening,and more than the screen dimming filter.

  • Giampi


    Reviewed in One (holo) app a day

    If you like me spend few mins in bed with the last internet updates install twilight. The developer claims you will sleep better. Not sure about it but definitely your eyes will be happy

  • Androfox


    Reviewed in Little helpers

    Helps getting sleep when using your phone before bed.

  • Pranav Ganapathiraju

    Pranav Ganapathiraju

    Reviewed in Things to Do, Places to Go…

    Don't let staying up late playing Angry Birds be the cause for loss of sleep. With this app, you get a software overlay on your screen, with a colour filter that gradually dims and brightens as the day passes. It's not as elaborate as Lux Auto Brightness. But, the simplicity of configuration feels better to me, personally. Also, the automatic mode is free. [Note: I don't play Angry Birds. I prefer Subway Surfers.]

  • Varna Sri Raman

    Varna Sri Raman

    Reviewed in Google Nexus Picks

    Changes ambient lighting on your device to red based on time of the day. Save your eyes.

  • Playboard Team

    Playboard Team

    Reviewed in Reddit Saturday APPreciation thread, Nov 23rd 2013

    syosyosyo: like fl.ux. this has helped me fall asleep so easily at night now despite my gadget use.

  • Simon John

    Simon John

    Reviewed in Must have apps for New android users

    If you get Eye Irritations when your using your phone at night this app changes the screen color from blue to red so you won't get irritated


Show me more

Are you having troubles to fall asleep? Are your kids hyperactive when playing with the tablet before bed time?
Are you using your smart phone or tablet in the late evening? Twilight may be a solution for you! Recent research suggests that exposure to blue light before sleep may distort your natural (circadian) rhythm and cause inability to fall asleep.

The cause is the photoreceptor in your eyes, called Melanopsin. This receptor is sensitive to a narrow band of blue light in the 460-480nm range which may suppress Melatonin production - a hormone responsible for your healthy sleep-wake cycles.

In experimental scientific studies it has been shown an average person reading on a tablet or smart phone for a couple of hours before bed time may find their sleep delayed by about an hour.

The Twilight app makes your device screen adapt to the time of the day. It filters the blue spectrum on your phone or tablet after sunset and protects your eyes with a soft and pleasant red filter. The filter intensity is smoothly adjusted to the sun cycle based on your local sunset and sunrise times.

Please read the basics on circadian rhythm and the role of melatonin:

Permissions explained:
- location - to find out your current sunset/surise times
- running apps - to stop Twilight in selected apps
- write settings - to set back-light

Automation through Tasker or other:

Examples of related scientific research:

Amplitude Reduction and Phase Shifts of Melatonin, Cortisol and Other Circadian Rhythms after a Gradual Advance of Sleep and Light Exposure in Humans
Derk-Jan Dijk, Jeanne F. Duffy, Edward J. Silva, Theresa L. Shanahan, Diane B. Boivin, Charles A. Czeisler 2012

Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans
Joshua J. Gooley, Kyle Chamberlain, Kurt A. Smith, Sat Bir S. Khalsa, Shantha M. W. Rajaratnam, Eliza Van Reen, Jamie M. Zeitzer, Charles A. Czeisler, Steven W. 2011

Effect of Light on Human Circadian Physiology
Jeanne F. Duffy, Charles A. Czeisler 2009

Efficacy of a single sequence of intermittent bright light pulses for delaying circadian phase in humans
Claude Gronfier, Kenneth P. Wright, Richard E. Kronauer, Megan E. Jewett, Charles A. Czeisler 2009

Intrinsic period and light intensity determine the phase relationship between melatonin and sleep in humans
Kenneth P. Wright, Claude Gronfier, Jeanne F. Duffy, Charles A. Czeisler 2009

The Impact of Sleep Timing and Bright Light Exposure on Attentional Impairment during Night Work
Nayantara Santhi, Daniel Aeschbach, Todd S. Horowitz, Charles A. Czeisler 2008

Short-Wavelength Light Sensitivity of Circadian, Pupillary, and Visual Awareness in Humans Lacking an Outer Retina
Farhan H. Zaidi, Joseph T. Hull, Stuart N. Peirson, Katharina Wulff, Daniel Aeschbach, Joshua J. Gooley, George C. Brainard, Kevin Gregory-Evans, Joseph F. Rizzo, III, Charles A. Czeisler, Russell G. Foster, Merrick J. Moseley, Steven W. Lockley. 2007

High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light.
Lockley SW, Brainard GC, Czeisler CA. 2003

Sensitivity of the human circadian pacemaker to nocturnal light: melatonin phase resetting and suppression
Jamie M Zeitzer, Derk-Jan Dijk, Richard E Kronauer, Emery N Brown, Charles A Czeisler 2000

Phase-shifting human circadian rhythms: influence of sleep timing, social contact and light exposure
J F Duffy, R E Kronauer, C A Czeisler 1996

Search for more evidence in many scientific articles and empirical studies online. Keywords: Circadian, Melatonin, Melanopsin, Light, Wavelength...

Similar to f.lux on Windows or Red Shift on Linux.

Users Also Installed

  • Twilight Pro Unlock Twilight Pro Unlock

    Twilight Pro Unlock

    Urbandroid Team

    319 ratings

    Thank you very much for your intention to support our development. This is a pro application for the Twilight app. Please install on top, do not uninstall Twilight first. Twilight Are you having troubles to fall asleep? Are your kids hyperactive...

  • Mindroid Mindroid


    Urbandroid Team

    1451 ratings

    Mindroid is an AVS (Auditory Visual Stimulation device - aka Mind Machine or Psychowalkman) app for Android. It provides each of your brain hemispheres with a signal (either audible or visual) with a slightly different frequency in order to...

  • Mindroid Unlock Mindroid Unlock

    Mindroid Unlock

    Urbandroid Team

    383 ratings

    This application is an Unlock for Mindroid Please install the Unlock if you like to access all options and features of Mindroid. Always install on top of the Mindroid free version. Mindroid is an AVS (Auditory Visual Stimulation device - aka Mind...

  • S Tools - Sensors and compass S Tools - Sensors and compass

    S Tools - Sensors and compass


    272 ratings

    S Tools is a pack of 5 different useful tools for your device. These includes •CPU frequency - Keep an eye on your CPU frequencies to see at what frequency your CPU was for how much time. •Sensors - A fully featured Sensor manager for your dev...

  • JB LockNow JB LockNow

    JB LockNow

    426 ratings

    JB LockNow is runs over Android 4.1(Jelly Bean). You can now swipe up from the system bar to quickly turn off screen. Google search with Google Now will start by swiping on the system bar, You can replace the Google search, will be able to turn off...

  • Sleep Lullaby Add-on Sleep Lullaby Add-on

    Sleep Lullaby Add-on

    Urbandroid Team

    611 ratings

    Add-on for Sleep as Android and Mindroid. Lullabies is a feature of the Sleep as Android alarm clock and sleep cycle tracker which help to fall asleep in a faster and fun way. Rather that fixed recordings our lullabies are real-time synthesized,...

  • Type Machine Type Machine

    Type Machine


    252 ratings

    Have you ever typed something and then accidentally erased it? Written down something important and couldn't find it again? App crashed and lost everything you wrote? With your own Type Machine, that's no problem. Type Machine saves everything you...

  • Photile Pro Live Wallpaper Photile Pro Live Wallpaper

    Photile Pro Live Wallpaper

    Joko Interactive

    790 ratings

    Photile turns any picture you choose into a grid of floating, fading, sliding tiles! Touch the tiles and watch as a shockwave ripples across your screen! Features: + Choose any picture on your device, including those taken with your camera or...

  • PowerLine PowerLine


    Urbandroid Team

    3363 ratings

    PowerLine - smart line-indicators in your status bar. Battery, CPU, memory, signal, WiFi, storage, SMS, missed calls, network usage and more... Better than a widget! Always visible, even on the lock screen. FREE version with two indicators, more...

  • SleepStats SleepStats


    Urbandroid Team

    2080 ratings

    NEW weekend/weekday filtering, sleep pattern heat maps. This application is an Add-on for Sleep as Android - the smart alarm clock which can track your sleep patterns, please make sure Sleep as Android is installed. This add-on brings advanced sleep...