When a tungsten-halogen
lamp
controlled by dimmers or any other control mechanism is run at a low voltage, the minimum
envelope
temperature necessary for the halogen cycle (250°C), is not attained. Reactivating the normal halogen cycle will contribute to the life of the lamp. This is done by letting the lamps burn at a high output for a few minutes after the show. A bright curtain call, if suitable, will have the same effect.
The quartz glass
envelope
should not be touched with bare fingers. Fingerprints are oily and when left on the bulb, they cause heat to concentrate on the oily area, causing an uneven distribution of heat on the glass surface. This causes rapid blackening of the glass and the eventual burnout of the lamp.
