After the application has been installed, click the light bulb in the Finder bar. A menu will open with two sliders. Drag the first slider left or right to adjust the luminosity, then drag the second slider to adjust the color saturation. If the screen is red, drag it to the left to decrease coloring and that's it. I tested the application on a Mini-Mac with MAC OS X 10.8.5 installed and it worked normally.