by soimless » Thu Feb 07, 2013 11:41 pm
As a warning to the weak of heart the following post contains copious amounts of (probably unnecessary) nerd rage.
Most electronic flashes ionize xenon gas not sodium-vapor. There are a variety of reasons for this. At low pressure sodium-vapor lamps produce a very monochrome spectrum of light. As seen in orange-yellowish street lamps. These lamps do not produce good color pictures especualy, for the pinkish skin tones found in human gentilia. Sodium-vapor lamps only produces a wide spectrum of light when it is operated at high pressure. It takes time for the sodium-vapor to heat up and reach such a pressure. So other gases like mercury or xenon are used as starter gases to increase the temperature of the sodium-vapor while still operating at a low pressure. Which is why some street lamps when first turning on are a very bright white light later shifting to a duller white color. The main thing with this is it takes time, on the order of seconds instead of 1/1000ths of a second necessary for a clean sync-able flash. Sodium is also very reactive and tends to eat at the electrodes in the bulb.
Xeon on the other hand, produces a very intense wide spectrum of colors (although most of it is in the UV and blue range). It’s a noble gas so it is non-reactive.Despite it's cost it's found in most flash bulbs today.
Just for the hell of it here is some spectral outputs of various noble gases in flash tubes from wikipedia.
As a warning to the weak of heart the following post contains copious amounts of (probably unnecessary) nerd rage.
Most electronic flashes ionize xenon gas not sodium-vapor. There are a variety of reasons for this. At low pressure sodium-vapor lamps produce a very monochrome spectrum of light. As seen in orange-yellowish street lamps. These lamps do not produce good color pictures especualy, for the pinkish skin tones found in human gentilia. Sodium-vapor lamps only produces a wide spectrum of light when it is operated at high pressure. It takes time for the sodium-vapor to heat up and reach such a pressure. So other gases like mercury or xenon are used as starter gases to increase the temperature of the sodium-vapor while still operating at a low pressure. Which is why some street lamps when first turning on are a very bright white light later shifting to a duller white color. The main thing with this is it takes time, on the order of seconds instead of 1/1000ths of a second necessary for a clean sync-able flash. Sodium is also very reactive and tends to eat at the electrodes in the bulb.
Xeon on the other hand, produces a very intense wide spectrum of colors (although most of it is in the UV and blue range). It’s a noble gas so it is non-reactive.Despite it's cost it's found in most flash bulbs today.
Just for the hell of it here is some spectral outputs of various noble gases in flash tubes from wikipedia.
[img]http://upload.wikimedia.org/wikipedia/en/thumb/2/27/Rare_gas_flashtube_spectral_outputs.JPG/572px-Rare_gas_flashtube_spectral_outputs.JPG[/img]