I've been looking for focusing aids for IR and UV multispectral imaging, and while browsing on a whim at our local salvage store, Urban Ore, in Berkeley, I happened across an item that might be useful. It's a vintage face tanning device with both a UV lamp and IR resistance-heating sources. I'm guessing it dates to the '50s or '60s. It's a German made device by "Dr. Kern & Sprenger, KG" and it runs on 220V AC. I picked it up for $10. I haven't checked, but I wouldn't be surprised if you could find one of these on eBay.
The IR heaters would radiate mostly in the thermal-range (3,000 to 30,000 nm, or 3-30 microns), outside the range of the CMOS sensors on most cameras, but they certainly also radiate in the near IR (700 to 1,300 nm). However, I'm thinking of disconnecting them or rewiring the switches because they draw a lot of watts and produce mostly heat. They can't be switched off while the UV lamp is on, unfortunately (the switches offer only IR "Wärme," or IR+UV "Sonne + Wärme"). I also have an IR LED flashlight from maxmax.com.
I'm trying to find out more about the UV lamp in this device, particularly about the spectrum it emits and whether there are modern lamps that I can replace it with to get specific UV wavebands. It appears to be a high-pressure mercury lamp, but could also be a low-pressure lamp. A label on the back of the device identifies it ("Typ UV Brenner") as a "UV800". I've attempted, but haven't yet found a way to remove the lamp to replace it. It emits quite a bit of visible light, and while testing it I've been wearing sunglasses with a good UV-blocking rating to protect my eyes, and I avoid looking at the lamp directly.
I'd also like to find out if I can attach dichroic or other filters in front of the UV lamp to specifically select certain wavelengths or wavebands of UV light. For safety reasons, I'd like to filter out any UVB and UVC. If anyone has experience with filtering for specific UV bands on the light source, I'd be interested to hear of your experiences. Other UV light sources for use as focusing aids would be welcome. I know others in this forum have made good suggestions for UV sources for actual imaging. For UV imaging, here's another example of a tunable UV light source:
"High Power UV LED Radiation System: 365nm 385nm 395nm 400nm 405nm"
Dr. Schmitt's blog is my favorite resource for UV photography, and his inventory of macro lenses is another fantastic resource:
The Macro Lens Collection Database
Thanks to Dr. Schmitt for permission to link to his sites here.
Anyway, apart from the novelty appeal and low cost, the tanning device is relatively small and light, and it has a nice hinge that allows the light to be directed at various angles. It's an interesting addition to my inventory for multispectral RTI.