Invert color

[Benzaa]

Hi,

Im looking for a way to invert the colors of the screen in XFCE.
My eyes are getting tired after reading for too long white PDF's.

I know that if I use gnome I just need to hit SUPER-N.
Is it a compiz feature?

Does anyone have an idea?

[easybake]

Yes it is a compiz feature. I believe it's called negative. It can be enabled in CompizConfig Settings Manager.