Stage Wash Coverage Calculator

The area lit by a stage light depends on its beam angle and how far it is from the stage. The diameter of the pool of light is about two times the throw distance multiplied by the tangent of half the beam angle. A fixture hung 6 meters above the stage with a 40 degree beam covers a circle roughly 4.4 meters across.

To make an even wash, the pools of light from neighboring fixtures should overlap, often by about half. The fixture count follows from the stage width and depth, the trim height, and the coverage of each fixture. Front lights from the house usually come from about 45 degrees above the performers to light faces without harsh shadows, and back and top washes add depth and separate performers from the background.

Different washes have different jobs, with front washes for faces, back washes and cyclorama lights for the backdrop, and top washes for general coverage. Check that the intensity is sufficient for the venue and any cameras, and consider color mixing and dimming. This is a planning estimate, and a lighting designer should confirm the plot for a real production.