I frequently have the problem where my laptop's screen is too dim prior to login and I can barely tell where my account or the mouse is. Is there a way to set the brightness to maximum on boot before any user has logged in by using the equivalent of an init script?

I've seen some useful applescript snippets here (How can I dim the screen from Terminal?) to adjust the brightness from the terminal, but I'm not confident these will work if no user is logged in.


creating an /etc/rc.local script

for i in {1 .. 1000}
    osascript /opt/utils/brighter.script

with an applescript script to brighten the screen

tell application "System Events"
    key code 113
end tell

only makes the screen a little bit brighter (perhaps a quarter of the way) and it doesn't seem to make much difference what number is used in place of 1000.


Trying to use screenbrightness in my /etc/rc.local appears not to work either. I suspect that the initial login screen that loads immediately is shown before the init script is executed.

1 Answer 1


Turn you screen fully bright. Open Terminal, type nvram backlight-level. Note the value. Create a logout hook to run nvram backlight-level=<value>. In my case the value was %a0%06.

If you run it interactively, you need to use sudo:

sudo nvram backlight-level='%a0%06'

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