Manually adjusting the Brightness and Warmth

[KoboClaraHD609]

I've recently bought the Kobo Clara HD and installed KoReader on it. Since I only read at night in the dark before bed, I thought the blue light filter on the Kobo Clara HD would suffice for that (I'm very sensitive to bright and blue light before bed).

Unfortunately, even at 1% brightness and maximal warmth settings on KoReader, it's still way too bright. I haven't used my Clara in weeks now since it keeps me up at night.

I read that it's possible to configure the "sysfs_light.lua" settings in order to decrease the brightness and increase the warmth/red colors and have been tweaking around with it myself without any success so far. I've also tried the settings on the following site (https://github.com/koreader/koreader/issues/4186) but I'm not sure if I'm doing things correctly in the first place.

I was wondering if someone else has some premade settings for lowering the brightness and increasing the warmth/red colors (/limiting the blue light emitted from the device) or can point me in the right direction what settings I should change and in what manner (increasing or decreasing the value).

I already found some other topics related to decreasing the brightness by changing the internal light of the device, but I'm not a very technical person and don't want to risk the warranty of the device.

I've attached 2 notepad files with my original "sysfs_light.lua" settings for KoReader and the latest settings that I've experimented with.

Anyway, thank you for taking the time to read this post!

[pazos]

IIRC - I might be completely wrong:

The warmth is fixed to 10 values, all these covered by KOReader. So it is impossible to "add more red"
The brightness might be different: there're 255 values and we map those to 100 steps. So each new brightness step covers 2.55 values.

It should be barely perceptible, but you can try it yourself writting 1 to your device's sysfs node.

Something like

echo 1 > /sys/class/backlight/mxc_msp430.0/brightness

would give you the minimum brightness the HW is capable.

[NiLuJe]

Yep, you'll have no control over the color mix on the Clara, only the brightness.

And I'm not entirely sure the scale isn't *already* 0-100 there, too?

IIRC, it *is* in the ioctl, which is what we use, and it also *is* for the sysfs *read* knob (actual_brightness), so, I'd assume it's the same for the *write* one .

EDIT: Yup, 1-100 on both counts over here (Forma & Elipsa).

(Which would mean, that, no, you can't do better than what's available in the UI).

[KoboClaraHD609]

I see... that's unfortunate. Thank you for your replies the both of you! Very much appreciated!