Azreal is right. 0.3 is the default setting, which is usually way too dark.
Lightsetting is not easy, you need a perfect match between all these factors:
-The detail texture you choose for each layer
-The colormaps you have painted
-The general lightsettings of the map
-The generated lightmaps on both terrain and statics
The BF2 engine is not bad at this, but it requires you to have an insight in to exactly how it works, sadly they didnt really had any reason to publicly explain how their lightmanages works, so unless you study every variable and how it affects your level, you will end up with a badly lighted map.
My best suggestion to anyone making their first level is to copy the settings from an official DICE map that has a similar light as the one you are making. And tweak it from there.
