Split Lighting
A portrait pattern in which the key comes from directly to one side, lighting exactly half the face and leaving the other in shadow.
In depth
Split lighting is the most dramatic of the classical patterns and the least forgiving: it emphasises texture, divides the face and reads as tense or secretive. A small amount of fill or a catchlight in the shadow-side eye keeps it from becoming a silhouette on that half.
Examples in practice
A strip light placed at 90° to a musician's face lights one side fully and leaves the other in near-darkness.