this mod is mostly to keep my Florence Duomo looking fine in 1.1 (even though the Duomo doesn't need it anymore since I switched it to a flatmap), but others might find it useful.

1.8 and beyond added void fog near bedrock level. This is not conducive to megabuilds that begin low. Fortunately there was a mod to remove it.

Unfortunately, 1.9 and beyond added a second effect when near bedrock: everything gets slightly darker. This mod removes both the fog and this second effect.

Vanilla Minecraft version 1.1 and up removes the fog if you are in creative mode (but not the dimming ugh). It also removes the fog AND the dimming if you are on a flat map. Use this mod to remove both of them no matter what: in survival, non flat maps, whatever

See the images for an example of

1. no voidfog but with dimming (creative mode)
   
2. no voidfog and no dimming (this mod)
   

Installation instructions
Jarmod version:
it's complicated now

Modloader/Forge version:
install Modloader or Forge
put the .zip in your .minecraft/mods folder

Minecraftforum.net thread for my mods; includes links to old versions