Display problem when adjusting brightness in ubuntu 12.04
I'm not sure how you're adjusting the brightness, but using xrandr, may yield different results.
As in xrandr --output VGA-0 --brightness 1.1 or 0.8 for darker, etc (see xrandr's output for your output name, maybe HDMI-0 or so)
[Q showed up in "Unanswered Questions", may help someone with a different brightness option. Probably will never get a reply from @Maverick Snyder though, last seen in 2013]