How to invert screen colors in Unity without using CCSM

Say I want to temporarily invert the colors on my screen for a better reading experience at night. However, I don't want to install CompizConfig Settings Manager and use its Invert plugin. How can I do it?

Solution 1:

Install xcalib package, e.g. in terminal (Ctrl+Alt+T):

sudo apt-get install xcalib

Switch to inverted colors in terminal using:

xcalib -i -a

And switch back using the same command.

Add the command (xcalib -i -a) as a new keyboard shortcut (nice choice is Ctrl+Alt+I) or to start up applications. (Edit: You may need to restart to be able to use the short cut.)

I'm using this regularly on Ubuntu 12.04 (with Unity) but also 10.04 worked as well as 13.10 works now. An alternative is magnifier -z 1 -fi from package gnome-mag, but this is no longer available in Ubuntu 16.04.

Solution 2:

Install Redshift. Redshift adjusts the color temperature of your screen according to your surroundings. This may help your eyes hurt less if you are working in front of the screen at night.

http://compizomania.blogspot.com/2013/01/redshift-ubuntulinux-mint.html