Umbra penumbra

Umbra penumbra

The shadow volume behind an object lit by an area light source (in contrast to a point light source) that does not have sharp boundaries, given that each point in the boundary area is only partially shadowed. The area or volume in full shadow is the umbra, the boundary area the penumbra.
References in periodicals archive ?
The event features metal bands Ceremonial Castings, Tormentium, Banewreaker, LORD, Maestus, Stalagmite, Vomit Violence and Umbra Penumbra beginning at 7 p.
Tormentium, Banewreaker, Vomit Violence and Umbra Penumbra are all Eugene bands.