Twilight: Blue light filter

Protect Your Eyes and Stop Letting Your Phone Ruin Your Sleep!

Struggling to wind down after scrolling at night? That harsh blue light from your screen is tricking your brain into thinking it's still daytime, wrecking your natural sleep rhythm (your circadian rhythm) and making it harder to fall asleep.

For those who experience light sensitivity (photophobia) or migraines, our app offers a visual sanctuary. It gracefully filters the harsh blue light spectrum that can act as a trigger. By also dimming your screen far beyond your phone's default settings, it helps create a softer, more comfortable display to ease your symptoms when you need it most.

For parents: Is your bedtime a battle after evening screen time? That blue light can keep kids feeling wired and restless. Twilight gently filters that stimulating light, helping them wind down naturally for an easier bedtime and a faster path to sleep.

After sunset, Twilight gently filters out the specific "wake-up" blue light (the 460-480nm range) that scientific studies link to delayed sleep. It bathes your screen in a soft, pleasant red filter that’s easy on the eyes and, most importantly, tells your brain it's time to rest.

WHY YOU'LL LOVE TWILIGHT:

😴 Fall Asleep Faster: Reclaim that "lost hour" of sleep. By protecting your melatonin (the sleep hormone), Twilight helps you wind down naturally.

👀 End Eye Strain: Perfect for late-night reading or browsing. Twilight's filter is gentle, and it can dim your screen far below the default settings for true comfort in the dark. Also a lifesaver for migraine-related light sensitivity!

☀️ Smart & Automatic: Set it once and forget it. Twilight automatically adjusts the filter intensity based on your local sunrise and sunset times.

🔒 Total Screen Coverage: Use our Accessibility Service (which is 100% private and never collects data) to filter your notifications and lock screen, so you're never blasted with bright light.

⌚ Wear OS Ready: Your smartwatch screen gets the same smart filter. Control it easily from a Wear OS Tile.

💡 AMOLED Friendly: Our smart dimming is designed to be safe for AMOLED screens and may even help increase screen life.

Based on proven science, Twilight is the perfect solution for anyone who uses their phone or tablet in the evening.

Ready to fix your sleep schedule and browse in comfort? Download Twilight and take back your night.

Documentation
http://twilight.urbandroid.org/doc/

Get more from Twilight
1) Bed reading: Twilight is more pleasant on the eyes for night reading. Especially as it is able to lower the screen backlight far below the ability of the backligt controls on your screen

2) AMOLED screens: We have tested Twilight on an AMOLED screen for 5 years without any sign of depletion or over-burning. If properly configured Twilight causes less light emission (by enabling dimming) with more equal light distribution (dark areas of the screen such as the status bar get tinted). This may in fact increase your AMOLED screen life time.

Basics on circadian rhythm and the role of melatonin
http://en.wikipedia.org/wiki/Melatonin
http://en.wikipedia.org/wiki/Melanopsin
http://en.wikipedia.org/wiki/Circadian_rhythms
http://en.wikipedia.org/wiki/Circadian_rhythm_disorder

Permissions
- location - to find out your current sunset/surise times
- running apps - to stop Twilight in selected apps
- network - access smartlight (Philips HUE) to shield you household light from blue

Accessibility Service

In order to filter also your notifications and lock screen the app may ask for enabling Twilight Accessibility Service. The app uses this service only to better filter your screen and does not collect any personal information. Please read more about this at https://twilight.urbandroid.org/is-twilights-accessibility-service-a-thread-to-my-privacy/

Automation (Tasker or other)
https://sites.google.com/site/twilight4android/automation