Wirehead Studios

Let me start off by saying that this is not a problem I've ever had before, but am now having on two separate computers with very similar settings. What happens is that Generations appears rather dim, both in menu and in game. Setting the brightness up in the menu doesn't seem to have any affect either. Even stranger, vanilla Quake 3 appears to be unaffected and can go up as bright as possible. I wonder if this isn't caused by my switch to 64bit Vista?

That does sound odd.  Try manually setting "r_gamma" at the console.  Higher values are brighter, and it should be decimal.  For example, "1" is default, "1.2" is brighter.  "2.0" would be VERY bright.  This is the setting that is affected by the "brightness" control in both Generations and normal Quake 3.  If it has no effect, try a /vid_restart from the console.  Let me know what happens.

Manually setting the brightness to default seems to have fixed the visuals themselves. If I try to adjust it in the menu from there it becomes dim again however. Trying to manually set the brightness up past the default gives me a reply of  "setdevicegammaramp failed". Likewise, /vid_restart throws everything back to the dim setting as well.

That's an error caused by a failed Windows API call.  That's either a driver issue or a problem with the OS.  Try checking this setting:

r_ignorehwgamma

Toggle it to 1 or 0, and see if it helps.  Also, check the following settings:

r_overbrightbits
r_mapoverbrightbits

Let me know what those are, as they affect brightness as well.

I'm sorry that it's taken so long for me to post back. The power supply in my computer went out the other day and I had to wait around on UPS. :P

Anyway... My settings show up as follows:
r_overbrightbits 1
r_mapoverbrightbits 2

Upon setting r_ignorehwgamma to 1, my menu seems to be at something akin to the default brightness. Once I loaded a map however it looked far too bright, lacking much of the atmosphere inherent.

As it is, I have added  "+set r_gamma 1" to my shortcut until I get this all sorted out.

Your overbright settings are correct.  As for the r_ignorehwgamma, try adjusting your brightness with that set to 1 and see if you still get the error.  Since you said your power supply went boom, you might start tinkering from scratch.  A bad power supply can cause all sorts of problems.

If nothing else works, try renaming your q3config.cfg in your generations folder to q3config.bak, and let Generations create a new one based on your working config in baseq3.  Test the brightness from that, and if it works, go on rebuilding your configuration from there.