Stage lamps are used for stage, studio, or television lighting. They are often made of quartz instead of glass to provide higher pressure ratings, higher melting temperatures, and more energy-efficient designs. Specifications for stage lamps include average rated life, lamp power, initial light output, and light center length. Average rated life refers to the average number of lamp-burning hours (hrs) that stage lamps produce. Lamp power is measured in watts (W). Initial light output is measured in lumens (lm). With stage lamps, light center length is the distance between the center of the arc tube and the light center’s reference plane

Specifications

Color rendering indexes and color temperature are important specifications to consider when selecting stage lamps and other stage lighting products. The color rendering index indicates a stage lamp’s ability to render colors in a natural way. Higher numbers indicate better color appearance. Color temperature measures the visual “warmth” or “coolness” of light from stage lamps. As a rule, higher values indicate whiter or “cooler” light. 

Filament Types

Stage lamps use slender, threadlike structure called filaments to produce light. Filament types that start with the letter "C" indicate a coiled wire filament. Filament designations starting with the letters "CC" indicate a coiled wire filament that is re-coiled. The letters or numbers after the prefix indicate the positioning of the filament. Common filament types for stage lamps include C-2V, C-6, C-7A, C-8, C-9, C-13, C-13D, C-2V, CC-6, CC-8, and 2CC-8. 

Selecting Stage Lamps

Selecting stage lamps requires an analysis of available lamp bases, most of which come in medium or mogul varieties. Medium lamp bases can be skirted, flared, bi-post, or pre-focused. They are found mainly in household lamps up to 300 W, and in some mercury and sodium stage lamps below 100 W. Mogul bases for stage lamps are also available in bi-post, pre-focus, and end-prong models. Typically, mogul bases are used in mercury, metal halide, and sodium lamps over 300 W. Stage lamps that require more than 200 V are more likely to have a mogul base than a medium base. Lamps with other tapes of bases may also be available from some stage lamp suppliers.