6/15/2010: "Protection from colored spells" means that Emrakul can't be the target of colored spells (including colored Aura spells) or of abilities whose sources are colored spells (such as the "when you cast" ability of an Ulamog, the Infinite Gyre that's been turned red by Painter's Servant). It also means that all damage that would be dealt to Emrakul by colored spells is prevented. Like every protection ability, it works only while Emrakul is on the battlefield.