a. The key light is the principal source of directional illumination
falling upon a subject or area. As the main or source light, the key should
dominate whatever its direction. The key light develops desired shadows.
(1) The normal position of the key light is in front of and to the side
of the subject (fig 4-9).
(2) Position and angle of key can be other that in front of and to the
side. The choice of position and angle depends on the emphasis and appearance
desired (fig 4-10).
Key light positioning