The characteristics of spark discharges in confined volumes of the gases nitrogen, carbon dioxide, argon, and helium are measured in the pressure range from 1 to 40 atm. It is found that both the brightness and efficiency of the discharge increase rapidly with pressure. The results of this investigation show that high pressure spark discharges can be used to produce extremely bright submicrosecond pulses of light having peak luminous powers in excess of 105W radiating into 4&pgr; sr over the wavelength range from 3200 to 7000 Å. Because the luminous area is localized to 0.01 cm2, a brightness of 107W/cm2is readily obtained.