Casting of Shadow

This spell seeks to harness the shadow energy inherent to an area.  Magical shadows spread from a point of your choosing to gradually fill an area of up to 40 feet foot-radius sphere for the duration.  Note: the darkness is confined to indoor areas or areas otherwise not exposed to outdoor sunlight and may not be cast outdoors in areas regularly exposed to sunlight.  Normal non-magical light sources are reduced to 20% of their normal radius as is darkvision.  Magical sources of light are likewise reduced to 20% of their normal radius unless they are cast at a higher level than this spell was cast at.  For each level above 2nd that the spell is cast at, the radius may be increased by up to 20 feet.

Note: This spell may be cast as a ritual, in which cast the duration is up to one hour so long as concentration is maintained.