By installing this mod, your Minecraft version will receive an immense graphic update. The default visuals are replaced by the incredible Shaders, what also reduces the FPS rate, if your computer is too slow.

It can work with OptiFine_1.8.0_HD_U_D2 but not D3 (install OptiFine before ShadersMod)
Forge can load it from mods folder but it may still have some graphics glitch.
It is normal that ShadersMod does not appear in Forge/FML mod list.
This is compatible with Forge 1486 but you cannot use it with OptiFine_1.8.0_HD_U_D2 at the time

Mobs do not flash red when hit. Creepers do not flash when they are about to explode.
Vanilla lighting are not completely eliminated when „old lighting“ option is off.
Poor performance chunk clipping.
Crash while toggling normal map or specular map. Not compatible with OptiFine_1.8.0_HD_U_D3.

Locate the minecraft application folder.
On windows open Run from the start menu, type %appdata% and click Run.
On mac open finder, hold down ALT and click Go then Library in the top menu bar. Open the folder Application Support and look for Minecraft.
Place the mod you have just downloaded (.jar file) into the Mods folder.
When you launch Minecraft and click the mods button you should now see the mod is installed.

ShadersMod v2.4.12 Installer for Minecraft 1.8