lights for wetplates

[TXFZ1]

People are building UV light boxes with them for alt printing.

David

[knuf]

I thought wet plate relied on UV light? Do they make LED's that emit high UV now?

well, some say combination of UV-rich light and vintage (uncoated) lens is fastest, but i would really doubt the UV transmittance of any glass. Looking at salted collodion spectral sensitivity, it starts at 500+nm, peaks at 450nm/420nm (bromide/iodide) and extends to UV.

But wikipedia says : "Most types of glass will allow longwave UV to pass, but absorb all the other UV wavelengths, usually from about 350 nm and below. For UV photography it is necessary to use specially developed lenses having elements made from fused quartz or quartz and fluorite."

So you still have only ~50nm of near-UV portion usable for exposure with common lenses. Next thing is that conventional UV-rich light sources as mercury vapor lamps or MH should be really considered as "hot", uncomfortable or even dangerous for sitter.

That`s why i think that in searching for ideal wetplates light, it would be better to find source which is rich in 400-500nm band and hybrid LEDs seem ideal in this. Broad blue light should be more comfortable as eye sensitivity is lower in blue (opposed to collodion) and LEDs can be switched on/off immediately and repeatedly or diminished (opposed to gas discharge lamps) saving the sitter from unnecessary exposure to near-UV/blue light (see UV / blue light hazard).

And the best thing : Those hybrid aquarium LEDs were designed by/for different community. Some manufacturers offer customized LEDs - you can have any combination of chips with wavelengths from 350nm to 800nm easily. So we could have a 90w LED with channels in 360nm,380nm,400nm,420nm,450nm.

[StoneNYC]

well, some say combination of UV-rich light and vintage (uncoated) lens is fastest, but i would really doubt the UV transmittance of any glass. Looking at salted collodion spectral sensitivity, it starts at 500+nm, peaks at 450nm/420nm (bromide/iodide) and extends to UV.

But wikipedia says : "Most types of glass will allow longwave UV to pass, but absorb all the other UV wavelengths, usually from about 350 nm and below. For UV photography it is necessary to use specially developed lenses having elements made from fused quartz or quartz and fluorite."

So you still have only ~50nm of near-UV portion usable for exposure with common lenses. Next thing is that conventional UV-rich light sources as mercury vapor lamps or MH should be really considered as "hot", uncomfortable or even dangerous for sitter.

That`s why i think that in searching for ideal wetplates light, it would be better to find source which is rich in 400-500nm band and hybrid LEDs seem ideal in this. Broad blue light should be more comfortable as eye sensitivity is lower in blue (opposed to collodion) and LEDs can be switched on/off immediately and repeatedly or diminished (opposed to gas discharge lamps) saving the sitter from unnecessary exposure to near-UV/blue light (see UV / blue light hazard).

And the best thing : Those hybrid aquarium LEDs were designed by/for different community. Some manufacturers offer customized LEDs - you can have any combination of chips with wavelengths from 350nm to 800nm easily. So we could have a 90w LED with channels in 360nm,380nm,400nm,420nm,450nm.

Very cool!

A friend, who does only WetPlate for a living (and he makes a TON off his work which are huge 16x22 size wet plates, once told me that he thought the whole lens thing was bunk, that he had used modern coated glass and there was no difference in exposure and the only reason he preferred brass was for the look he could get, not the "un-coated-ness" of the older lenses. So I'll just throw that out there as second hand knowledge. Would love someone to double blind that test.

But the UV LED's are a neat idea, varying and controlling the frequency, neat!

[Mark Sawyer]

A friend, who does only WetPlate for a living (and he makes a TON off his work which are huge 16x22 size wet plates, once told me that he thought the whole lens thing was bunk, that he had used modern coated glass and there was no difference in exposure and the only reason he preferred brass was for the look he could get, not the "un-coated-ness" of the older lenses. So I'll just throw that out there as second hand knowledge. Would love someone to double blind that test.

I'll confirm from first-hand experience, the AR coatings don't affect exposure times on wet plate. I often switch back and forth between coated and uncoated to control contrast. If people aren't doing this, they're sacrificing a valuable option...

[cgrab]

Eric Antoine (http://www.ericantoinephoto.com/) recommended using 250w compact fluorescent light bulbs at a Workshop I took with him. You can get them at "grow-shops", most other lighting sources will not have them in stock, but might order them.

[Tobias Key]

Eric Antoine (http://www.ericantoinephoto.com/) recommended using 250w compact fluorescent light bulbs at a Workshop I took with him. You can get them at "grow-shops", most other lighting sources will not have them in stock, but might order them.

Interesting. Just hope the police aren't watching the store when you emerge with enough lights to start a small drug empire!

[Mark Sawyer]

Interesting. Just hope the police aren't watching the store when you emerge with enough lights to start a small drug empire!

Especially when you also buy the biggest grow-tent to use as your darkroom!

[goamules]

To me, the best light for wetplate is that which is free: the sun!

[cgrab]

Interesting. Just hope the police aren't watching the store when you emerge with enough lights to start a small drug empire!

Wet-plate mugshot selfie!
Because the Police have gone all digital nowadays.

[MAubrey]

Eric Antoine (http://www.ericantoinephoto.com/) recommended using 250w compact fluorescent light bulbs at a Workshop I took with him. You can get them at "grow-shops", most other lighting sources will not have them in stock, but might order them.

They're online, too, for about $50 a pop. How many do you think we're talking about for a decent exposure? A 250w CFL is like a 900w Halogen in terms of lumens, but obviously, that's not UV...