discharge lamp

HID (High Intensity Discharger) CID (Compact Indium Discharge), CSI (Compact Source Iodide), xenon and most importantly for shooting purposes, HMI (Hydrargyrum, Medium Arc-length Iodide), are lamps containing special gases under pressure (some high, some low pressure) through which an electric arc is discharged to produce a highly efficient light source. They require a Ballast and starter. Their Color Rendering Index and Hot Restrike Time vary. Lamps may require individual Color Correction with gels. Also see: HMI.