Darkness

Area 
Cloaks the area of effect in pitch darkness. A person inside the area can see out normally, but can see nothing else within the area. Those outside the area can see only darkness within. Thus, attacks out of darkness suffer no penalty, but attacks into darkness are at a penalty; see p. B394 for combat rules. 
The Dark Vision (P, X) advantage lets you see through a Darkness spell, but Night Vision (P) and Infravision (P, X) do not.

Duration: 1 minute. 
Base cost: 2 to cast. 1 to maintain. 
Prerequisite: Continual Light.

Item 
Floor, ground, or a rug can be enchanted so that the area above (about 6 feet) is in permanent darkness. 
Energy cost to create: 12 per square foot.