Blue light at night is bad for us for a few reasons, including affecting our sleep or straining our eyes. Blue light can confuse your circadian rhythm, disrupting melatonin production in the brain, and inducing a lagged sleep schedule. It can also lead to increased eye strain in low-light, especially upon waking up or going to bed. On Android, you get many applications which generate an overlay to cancel out blue light, and OEMs have begun adopting blue light filter features as well. Normally the third party options don't work too well and prevent the user from doing things that won't work with overlays, such as application installers. This is a security feature, but can be annoying for the end user. Thankfully there are other, better options available such as Night Light using KCAL.

Thanks to KCAL, we have the option to manipulate Qualcomm's post processing on-device with root access. This means rather than running an overlay, we can simply change how the colours are displayed instead at a driver level. This is more efficient and can be made a lot simpler, thanks to the free and open source application "Night Light".

[appbox xda com.corphish.nightlight.generic]

Simply install the application and you can enable it from the get-go, or even better enable it on timed schedule. This means you can benefit from it when going to sleep, but not be annoyed by the weird looking colours during the day. Give it a try!