Monitor not displaying color red. Is this the monitor or some setup I'm missing? I've plugged the monitor into both an iMac 2006 and a MacBook 2008. Red shows up as black. I've set up the monitor in System Preferences and on the monitor itself. The color red simply shows as black. Is there something I'm missing or is the monitor likely broken? 

I've searched online and can't find similar issue. 

Edit: Now I'm *really confused: can't be the monitor, because I tried plugging a different monitor (from a friend's computer) and I have the same problem.
There are applications that let you control how much of each color component in the display generated by your machine gets to the monitor. An example of this is Dark Adapted.

These are useful for adjusting your monitor for night time viewing, and other special cases. Unless you have something like this running on BOTH the machines, it's likely that the problem is either with the monitor itself, or with the cable.

Are you connecting via VGA or DVI? A problem with the cable wouldn't manifest like that on DVI, but could on VGA, where individual pins literally correspond to component colors. If on VGA, try another cable and see if that helps. If that doesn't work, it's most likely that the monitor is broken.