HOW TO CHANGE YOUR VIDEO CARD'S GAMMA SETTINGS
 Right click on a clear area of your desktop and chouse properties in the menu
 
This will bring up your Display Properties Window, and should look somthing like this.
 
Pick the tab Settings and you should see something similar to this.
Pick Advanced and you will then get into the area to change your gamma settings.  This is where your display windows will probably be different from mine.
 So inorder to explain a few things I have shown you my display windows.
This is what I get when I chose Advanced
As you can see I get a lot of options of things to play around with my Radeon card. 
Which tab your Gamma settings will be at I don't know but a good guess would be color.
As you can see under my color tab I get the gamma settings.
Your display screen may only have the slide bars for Gamma Brightness and Contrast, or maybe just the Gamma bar. 
You may then also have a lot more to play with than what I have.
This is the default settings for my computer.
Below is the settings I use for DoD.
The line graph shows the change and what it actually is telling me is beyond me other than it shows things are off the default settings. When I change anything on this window I can type in a description in the Profiles for: Desktop and save that profile.  So when I want to play DoD I just now have a pull down menu and it sets everything accordingly.  With my card the Full Screen 3D if set on allows me to set up a profile that turns on the settings as soon as I start the 3D application.  It also allows me to set HotKeys so I can change the gamma, brightness and Contrast in while in the application.  I had thought this would work inside the game but it doesn't.  So I'm not sure if I am doing something wrong or if DoD is not considered a Full Screen 3D application.   But I have found these settings I use is good throughout all the maps even the really dark ones that are for night and dod_forest.  I can see someone across the map as they move around in forest.  And this is not a cheat or anything as there is no effect to fog settings. It only changes how shadows appear.  
You don't have to change the gamma and things by much to see a hugh difference. 
Experiment with it and good luck.  I think you'll love the results.