For general purposes, it is desirable to provide what are called washes of light. Washes are general, unfocused light designed to
evenly light a certain area of the stage. Typically several different
washes are used to give each scene a different feel. Often several
instruments are used that can be used for general purpose filling of
dark spots and other effects.
Obtaining a usable dim wash is a task many lighting designers face.
Many novice lighting designers think that a satisfactory dim wash can
be obtained with only a few instruments. The truth of the matter is
that it typically takes more instruments running at lower levels to
produce a usable dim wash.
Fresnels and PAR cans are most frequently used for washes.
Ellipsoidal instruments may also be used if they are shot from far enough
away or defocused.