RLOD#36 (2020.06.20) 2011 Osram HMI 12000W GS

The development of the motion picture industry, and of outdoor film sets in particular, has set new requirements for stage lighting which needs light in very large quantities in order to compensate first for the weak sensitivity of early film stocks, and later to emulate sunlit scenes during cloudy days or even at night. This pushed first the development of large incandescent lamps operating at high temperature, and later resulted in the use of high-wattage flaming arcs (with cored carbon electrodes operating in air) for the most demanding applications. The latter were eventually replaced during the 1980s by large metal halide arc lamps following Osram's invention of the rare-earth-filled HMI in the late 1960s. The first viable alternative to powerful carbon/flaming arcs appeared in 1982 with the 6 kW HMI, followed by the 12 kW variant released in 1984. The latter produces over one million lumens of artificial daylight (6000 K at 95 Ra8) and features an extremely bright arc that enables a very effective control of the emitted light. The lamp shown here is a later variant with a shaped burner and a reduced electrode gap length for a brighter and more stable arc. That lamp is truly massive but its burner is relatively small given the enormous amount of power dissipated between its electrodes. That's the requirement for this sources's extreme performances (96 lm/W) but also the cause of its relatively short life (500 h).