Quality of emitted light[edit]
The sulfur plasma consists mainly of dimer molecules (S2), which generate the light through molecular emission. Unlike atomic emission, the emission spectrum is continuous throughout the visible spectrum. As much as 73% of the emitted radiation is in the visible spectrum, with a small amount in infrared energy and less than 1% in ultraviolet light.
The spectral output peaks at 510 nanometres, giving the light a greenish hue. The correlated color temperature is about 6,000 kelvins with a CRI of 79. The lamp can be dimmed to 15% without affecting the light quality.
A magenta filter can be used to give the light a warmer feel. Such a filter was used on the lamps at the National Air and Space Museum in Washington, D.C.[3]
The addition of other chemicals in the bulb might improve color rendition. Sulfur lamp bulbs with calcium bromide (CaBr2) added produce a similar spectrum plus a spike in red wavelengths at 625 nm.[4] Other additives such as lithium iodide (LiI) and sodium iodide (NaI) can be used to modify the output spectra