ABSTRACT
This chapter explores the major lighting instruments used in the theatre. The lenses, or lens systems, used in theatrical lighting instruments are grouped into two general categories profile and wash. The multiple plano-convex lens trains and fresnel lenses used in most stage lighting instruments absorb less light than a single thick lens with the same focal length. The primary light source for conventional stage lighting instruments is the tungsten-halogen lamp. An incandescent lamp comprises a glass bulb that houses a tungsten filament in an inert gas environment at near-vacuum pressure. Fresnel lenses are used in fresnel spotlights. The plano side of these lenses is finished with a surface treatment to diffuse light. Glass reflectors are becoming widely used in the current generation of ellipsoidal reflector spotlights. The color of light is measured by using the color temperature scale. The sole purpose of the color temperature scale is to accurately describe color.
