Does anyone have experience with the Sunmaster Cool (6000K) 1000Watt UV light for contact printing processes? This is a "grow-light" for hydoponic gardening, but seems to have a more perfect cool light spectrum distribution for UV printing than the 5000K Venture lightbulb that Sandy King writes about in his article at Unblinking Eye about UV light sources.
Those color temperature readings are really misleading. There are actually MH bulbs that are rated at 20k!
Thanks for that reference! I still feel pretty good about the spectrum of the Sunmaster lamp from what I read in the above reference. The only thing that worries me is the amount of UV that gets through the lamp glass. This appears to be variable because:
"The single ended lamps used in the [aquarium] hobby are surrounded by a borosilicate glass bulb that absorbs a significant amount of the UV"
I'll have to check what kind of glass the Sunmaster uses. Since it is not made for aquarium use, I'm hoping the "grow-lite" characterisitics are more in line with what the alternative photographer needs. It still looks like the distribution of light energy is a good one from the spec sheet. It is a broad range light energy source and contains spectral energy from red all the way up. It is just concenetrated in the blue/violet range. This lamp is also made by Venture. I'm hoping they know something about light.
In the end, only a good trial of the lamp is what's important. I can't wait to see what I find. The only thing I have to compare with though, is a homeade light box with flourescant tubes. I also don't have a densitometer to measure outcomes like Sandy King did in his article on UV light sources.
The reason I didn't build my own light box (or put it on my hubbys HoneyDo list) is because I read somewhere that the tubes can cause a wave-like pattern on the print during exposure (don't think that came from Sandy's article?), and the theory of the advantages of a semi-columated light source sounded reasonable to me. The MH unit is also much cheaper than any other solution I've found. I would consider a "plate-burner", but have not found one locally yet that I can get for a good price. I would also consider just using sunlight in the summertime (the most perfect light source), but feel I would need a light integrator like the Metrolux or Zone VI. Those guys are way more expensive than this lamp. So until I'm able to afford some other avenue, I'm going to try this Sunmaster...
Wish me luck...
I would agree that spectral output and color temperature are two only loosely related scales. Generally speaking, however, an actinic (violet and ultraviolet) bulb intended for saltwater reef aquaria and vegetative plant growth (don't ask me how I know this) will work well as an UV light source for printing. I use a plain Jane GE 400W MV with excellent results. My print times for Pd using dense negatives range from a minute to around 30 minutes. Granted I could do much batter with a 1000W setup, but I had a 400W (for another use) laying around, so that's what I use.
Borosilicate glass only absorbes 'hard' UV light, so this shouldn't be a problem. My only suggestion would be to experiment.
After doing the research my best candidate would be cotinuous arc xenon lighting, but the bulbs and power supplies are complicated and expenisive.