Want a screen filter that *only* filters out blue light

[Chriswaterguy]

I want a screen filter for use at night, to remove some or all of the blue light from the display. (Blue light affects our circadian rhythm, makes us less inclined to sleep, and has a number of health effects if we get too much at night.)

Major problem with apps I've tried: I just need to remove the blue light, but the ones I've tried actually add light - so black becomes yellowish when it should stay black, adding to the screen glare instead if reducing it, and reducing contrast.

I've tried Night Filter (dev: digipom) and Filter Your Screen (dev: KP), and they both have this problem. Is there a technical reason that Android apps can't do what I'm asking?

I know there are screen filters to reduce overall brightness - these are a great partial solution, but I'm specifically asking here about color filters.

FWIW, I have an AMOLED screen on my Note 2 and an LCD screen on my Note 10.1. Thanks!

 

[funkylogik]

The trouble is that if you imagine white as being made up of equal levels of red green and blue, if you filter out the blue, you cant possibly have white lol what we see as white is our eyes sensing every colour of the visible spectrum so take away the blues and our brain wont see what we call white. Hope that makes sense
EDIT sorry i re-read. Dont know why the apps are affecting the blacks on an amoled display

 

[Chriswaterguy]

@funkylogik, yeah, I actually *want* the whites to change, to go more yellowish ("warmer").

Looking at the advanced settings for JuiceDefender Ultimate, under controls > "night tint", it says that altering the color temperature cannot be done in Android due to system limitations. I guess that's my answer, for now

JuiceDefender Ultimate can apply a night tint to somewhat approximate changing the color temperature. It's subtle, but seems helpful, and not glare-y. I'll keep trying it out.

 

[funkylogik]

Just be sure to use ONLY that function of Juice Defender. Dont be tempted by its task killing functions
Surely at least with root access an app could just switch off the blue LED. Good luck with that anyway and let me know how it goes

 

[lexluthor]

Lux allows you to choose the color temperature for night mode using a slider. Would that help?

 

[funkylogik]

I havent tried Lux but i thought it only adjusted brightness. Might check it out