Ultraviolet and visible light output were measured for 11 commercially available flash attachments and 1 studio flashlamp. Both dose and spectral distribution were determined. The UV doses received per flash at 1 meter distance and maximum flash time length, were compared with that received by illumination with an incandescent bulb for 1 hour at 50 lux. The lamp with the highest UV output reached the equivalent in 9 flashes, the one with the lowest output did the same in 220 flashes. The average was 50. Most flashlamps had a UV absorbing layer, which absorbed up to 91per thousand of the UV between 300 and 400 nm, as compared to an unfiltered xenon lamp.