How do dim screen, even if artifically, below the minimum? My laptop (a Toshiba Sattelite) runs far too bright, even in the ambient light from outside in the day, and I need to be able to dim it below its minimum setting. ~#cat /sys/class/backlight/acpi_video0/brightness ~#0 Setting it below 0 will not work, and apps like `flux` even with some hackery to force it to night mode via script by rolling the timezone fails to do too much and leave colours of course yellowed. Is there some sort of method to set it below its minimum somehow? (uses some integrated nvidia card by the way) Is there a program I'm missing that will artificially dim it by overlaying transparent black?

With `xrandr` you can affect the gamma and brightness of a display by altering RGB values.

From `man xrandr`:

* `--brightness`

> Multiply the gamma values on the crtc currently attached to the output to specified floating value. Useful for overly bright or overly dim outputs. However, this is a software only modification, if your hardware has support to actually change the brightness, you will probably prefer to use `xbacklight`.




I can use it like:


xrandr --output DVI-1 --brightness .7


There is also the `xgamma` package, which does much of the same, but...

* `man xgamma`:

> Note that the `xgamma` utility is obsolete and deficient, `xrandr` should be used with drivers that support the XRandr extension.




I can use it like:


xgamma -gamma .7