MAKE SURE YOU HAVE OPTIFINE/MCPATCHER!
Official Curse Download:


You can see here that it's as accurate as Not Enough Items, but it's just a resource pack. The only mod you need installed is Optifine and/or MCPatcher because it takes advantage of the Custom Color feature provided by both mods.To use, install either Optifine or MCPatcher then load the resource pack.Mob Spawn Finder still shows spawning spots during broad daylight so you don't have to wait until night to see where your dark spots are.As long as your floor stays green, no mobs will spawn!This image highlights the distinction between light levels of 7 and below, and levels 8 and above. Normally it can be difficult to tell if you have enough torches, especially with variable brightness settings, but now you can easily scan your world to check for dark spots.