Wet plate / artificial lighting

[BarryS]

In the past when I need small I built lights based on four 55w 21" 5500k fluorescent bulbs from an aquarium supply, but these weren't so cheap, and the Fotodiox uses twice as much power. If course, this might not equal twice as much light, but still, it looks like a nice product. How is the finish on it Barry?

Jason-- For a $135 fixture, I'm very happy with the build quality of the Fotodiox units. I've got a wide variety of lighting instruments--Hensel, Balcar, Norman, Arri, and Kino-Flo--and the Fotodiox units are pretty decent in comparison.

@ Cyrus-- 20"x24"? You're going to need a lot of UV for an f/9 portrait sitting. That's a lot of radiation. You can run 4-5 Fotodiox units off a 20 amp circuit, but 6-8 units would be painfully bright. There's not going to be any easy solutions for what you're trying to do.

[cyrus]

There's not going to be any easy solutions for what you're trying to do.

That's what I'm starting to think.
Seems to me that ULF wet plate requires easy access to outdoors shooting, which would impose various restrictions on your photography style/content. If that is the case, I may still go with a ULF plate camera but only if I manage to make dryplates that respond to "normal" light. So I guess time to buy gelatin instead of collodion...

[cyrus]

Probably - looks like a high-pressure street lamp. But the UV output should be very limited unless these ones are some illegal high-risk device. Approved stage or club blacklights are supposed to be UV safe, and most of the light would vanish in the filter glass.

I think "UV safe" means no UV-C radiation (the type used for sterilization in hospitals) but it has to have UV light because (back in my clubbing days ) these sorts of lights could make your girlfriend's teeth glow on the dance floor, 50 feet away!

[E. von Hoegh]

I think "UV safe" means no UV-C radiation (the type used for sterilization in hospitals) but it has to have UV light because (back in my clubbing days ) these sorts of lights could make your girlfriend's teeth glow on the dance floor, 50 feet away!

Due to the fluorescent "whiteners" put in toothpaste. Laundry detergent, too

[cyrus]

Thinking about this some more - I wonder why UV light works for collodion at all. Doesn't the glass on the lens block the UV, leaving perhaps only the blue/purple light to actually cause the reaction? In that case, instead of getting a UV light, I should experiment with blue colored lights! (If your lens uses quartz, that would be different but I am sure there are no quartz lenses)

In fact we still have to pin down the spectral sensitivity of wet plate collodion. It would vary depending on the chemistry - Bromide, Iodide, both etc. I would guess they average peak at about 420-450nm - that's purple/blue not really UV which begins from 400nm - -in which case I would need BLUE gel filters not UV lights (or, really cheap UV lights that leak a lot of blue!...or maybe mix n match)

[BarryS]

Salted collodion is sensitive over a range from blue through near UV wavelengths. Glass still transmits a good proportion of UV--especially in the range of collodion's sensitivity. I'd love to test a Kalosat lens with quartz elements to see the difference in exposure--but they're sort of...scarce. I still have to take Scott up on his offer to test out his non-uv coated flashtubes. There's theory--and then there's practice. Can you find some studio space with large windows--a loft? Nothing beats the sun for collodion and you don't need quartz windows.

[Jason Greenberg Motamedi]

Sometime back I read about an experiment using Daguerreotypes (similar color-blind sensitivity as Collodion) in which results from a special Zeiss Planar lens designed for passing UV light were compared to a regular lens. Interestingly the Planar was only negligibly faster than then the regular lens, suggesting that the the UV blocked by glass is not all that important to our exposures.

[Sevo]

I think "UV safe" means no UV-C radiation (the type used for sterilization in hospitals) but it has to have UV light because (back in my clubbing days ) these sorts of lights could make your girlfriend's teeth glow on the dance floor, 50 feet away!

Tooth (and dayglo paint) fluorescence is stimulated by a spectrum range from visible blue to near UV. Even plain blue ultrabright LEDs do it (these deliver no UV at all).

[Sevo]

I would guess they average peak at about 420-450nm - that's purple/blue not really UV which begins from 400nm - -in which case I would need BLUE gel filters not UV lights (or, really cheap UV lights that leak a lot of blue!...or maybe mix n match)

Deep UV might not do much in terms of silver photography - in the print lab at the academy the short-arc UV lit contact frames and process cameras were for screen printing and lithography, whose bichromate gum and azo coats are sensitive in regions of the spectrum far off the visible light.

[cosmicexplosion]

well i think its time to do a test.