Product Description:
BlackLight allows you to invert the colors on your screen. It does so by inverting the gamma curve of your screen. When you open BlackLight, it automaticly invert the screen. When you quit it, the corlors revert to normal. Clicking on the BlackLight icon in the Dock toggle between inverted and normal screen.
What's new in this version:

* Improved the inversion algorithm to respect the gamma correction curve in use on the screen. Previously the gamma correction was inverted when the colors were, the correction was applied in reverse and could make gray levels appear coloured.
* Added the color filter effect to the Black Light application.
* Black Light is a universal binary that can work nativly on Mac OS X for the Intel processor.

WHY SHOULD ONE WANT THIS?