Something is filtering blue light and I can't figure out how to stop it

Question

I just got a Samsung Galaxy S9 last week and since day 1 it has been applying a blue light filter even though I turned blue light filter off in the settings (Blue Light Filter turned off and also schedule turned off under Settings/Display/Blue light filter).

The blue light filter's behavior is strange. The filter turns on around 6:56 every evening and turns off around 5:56 in the morning. Sometimes when I unlock my phone the filter isn't applied and a split second later I see it get applied. Even less often I see it applied in blocks quickly filling the screen. If I turn blue light filtering on in Display settings, the affect is additive.

When I got the phone all of the applications from my previous phone, a OnePlus 3, were installed, so I supposed it could have been one of those. I went into application permissions and turned off overlay permission (Settings/Apps/Special Access/Apps that can appear on top) to everything I thought might be affecting the screen color.

What else can I look into? Is there a way to check every process that's running to see what is changing the screen color?

— Matt Casto | Sources

Answer

So I did a bit of digging and found two related threads describing your problem:

User Friendly Solution

As you've described you had transferred over your settings from a different device and the 'Night Light' settings were hidden by the Samsung software.

The most user friendly way is from Reddit:

PSA: Night Light and Blue Light Filter Overlap

where the solution is use Nova Launcher and to create a Night Light shortcut from Nova Launcher:

Easy fix is through Nova Launcher / Activities. Press somewhere on the home screen so you can select widgets. From there select Activities>Settings>Night Light. Open Night Light from your home screen and turn it off - and the scheduling, too, of course... Unless you'd rather use Night Light.

Reddit author made a video for visual aid: https://youtu.be/J9J1B2Q8Eu4

Alternate ADB solution

In my research I also found a different way, and while it didn't help you perhaps it may help someone else:

Weird Night Mode type issue

The XDA one lists adb commands to try:

Using adb to list out device settings

adb shell 'settings list secure

and then attempting to clear the appropriate ones:

adb shell 'settings put secure night_display_activated 0'



adb shell 'settings put secure night_display_auto_mode 0'

— Morrison Chang | Sources

Something is filtering blue light and I can't figure out how to stop it

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