You have probably noticed it yourself but its never actually pitch black in minecraft. Even if you are in a cave with no torches you will still be able to see something independent of your gamma setting. This mod changes this, it removes the minimum block & sky light so if there is no light source its actually dark.
After you install this mod it will be in mode 0, there are 3 different modes and they can be changed in the config file:
0. There is no minimum block & sky light
1. There is no minimum block light
2. There is no minimum block light & the sky light is dependent on the moon phase
There are also some other options in the config file:
"Dark Nether" : "Whether the minimum light of the nether should also be removed"
"Dark End" : "Whether the minimum light of the end should also be removed"
"Dark Twilight Forest" [1.7.10] : "Whether the time in the Twilight Forest should be fixed to midnight instead of dusk"
"AlternativeNightSkylight" : "In Mode 1 & 2 the skylight has a slightly blue tint, this option replaces that with a slightly green/yellow tint"
"Dimension Blacklist" : "A list of dimension ids separated by "," in which Hardcore Darkness will not take effect"
If you install this mod on a server all clients will have to have Hardcore Darkness installed. Clients will also be forced to use the config file you specify on your server.