Which term refers to making adjustments to the arrangement of lights for optimal effects?

The term that refers to making adjustments to the arrangement of lights for optimal effects is "focussing." In a theatrical setting, focussing involves refining the angles, intensity, and position of the lights to achieve the desired look for a scene or stage area. This process ensures that the lighting complements the actors and set design, highlighting key moments and creating the right mood for the production.

Focussing is a crucial part of lighting design, as it directly affects how the audience perceives the performance. Properly focussed lights can enhance visibility, draw attention to specific areas or performers, and contribute to the overall atmosphere of the piece.

The other options do not pertain specifically to the adjustment and arrangement of lights:

• Crossfade refers to transitioning smoothly from one lighting state to another.
• Fade up/down describes the gradual increase or decrease in light intensity.
• The term spotlight refers to a specific lighting instrument designed to highlight a particular area or performer on stage.

Understanding these distinctions helps clarify why focussing is the correct choice when discussing adjustments to lighting for optimal effects.