Re: DIY cold light...greenspun.com : LUSENET : B&W Photo - Printing & Finishing : One Thread
Need someone who can explain the kind of bulbs used in cold light heads such as those made by Aristo. Have found a good source for scientific grade opal glass for diffusers, but I need to know if the tubes are nothing more than flourescents...
-- Bob Kaczka (firstname.lastname@example.org), October 07, 2000
The tube used is essentially a fluorescent disharge tube, but it's specially shaped to give an even spread of light over a specific area. That is, it's formed into a folded grid or serpentine shape.
The gas filling and coating of the tube aren't standard either, the blue output of the tube is maximised.
In addition to all that, a much higher than normal voltage is used to operate the tube, so that it strikes without the necessity for hot filaments and 'starter' circuits.
-- Pete Andrews (email@example.com), October 09, 2000.
The cold-light head on my Omega D-2 uses a normal 40W circular flourescent rapid start tube. That's it, nothing fancy.
-- Brian C. Miller (firstname.lastname@example.org), October 09, 2000.
Aristo will sell their tubes as replacements. They might even tell you what circuitry you need. However, as I see it, all the pain and trouble to make your own will end up costing more than buying one outright. Single tube models are about $200 for a new one for 4x5 units. You could easily spend that in making it yourself.
-- Charlie Strack (email@example.com), October 09, 2000.