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Edanylycha
27-Feb-2017, 06:19
Hello all,
I am very new to this style of photography, I've just finished building my own 8x10 wet plate collodion camera and have just begun mixing my first batch of chemicals. Seeing as this is all experimental for me I'm trying to keep it low budget. Has anyone had any experience with using LED lighting for studio wet plate photography? Any information will be greatly appreciated!
Many thanks,
Ethan

Jim Noel
27-Feb-2017, 09:38
I haven't tried it with wet plate, but if any LED's will work it will be those which put out in the UV spectrum. The "white light" ones may also work.

goamules
27-Feb-2017, 11:32
Mark will weigh in soon, but you need a LOT of light for wetplate. Compact florescents, blacklights, and all the rest have been used. But usually fail. They can create a weird skin tone, or the sitter has to be staring into 3 banks of light with as much candlepower as the sun. It's ISO 1 afterall. Mark uses strobes to good effect.

Edanylycha
27-Feb-2017, 16:35
I've read that lights in the 5500k range are correct for wet plate, Is this accurate?

Mark Sawyer
27-Feb-2017, 20:45
Mark will weigh in soon, but you need a LOT of light for wetplate. Compact florescents, blacklights, and all the rest have been used. But usually fail. They can create a weird skin tone, or the sitter has to be staring into 3 banks of light with as much candlepower as the sun. It's ISO 1 afterall. Mark uses strobes to good effect.

Oh yeah, drag me into it... :rolleyes:

I haven't played with LED's, so I can't comment other than the already stated need for UV and blue wavelengths. But I've used CFL's for still life, (yup, 5500k, Edanylycha) with good results. But for portraits, any hot lights will make the subject very uncomfortable, which generally has a very negative effect on the results. Go with strobes there.

DKirk
28-Feb-2017, 02:20
More for the printing side of things, but you could have a look at http://thewetprint.com/en/2016/09/16/exposure-unit-part-1-design/ to give you a rough idea for one way to use LEDs. Though if you're photographing people, I'd go with a mix of the UV he uses, blue and perhaps some of the white "daylight" (check the specs for the LEDs see which kick out the most towards the blue end of the spectrum)

seezee
1-Mar-2017, 09:47
The UV wavelengths needed to properly expose may be damaging to your subjects' eyes! Better have them sign a waiver if you plan to go that route.

Mark Sawyer
1-Mar-2017, 13:38
The UV wavelengths needed to properly expose may be damaging to your subjects' eyes! Better have them sign a waiver if you plan to go that route.

"The UV wavelengths needed to properly expose" are equivalent to standing in the sun for two seconds (about the normal exposure for an outdoor wet plate portrait). Unless you know something I don't?

seezee
1-Mar-2017, 18:11
"The UV wavelengths needed to properly expose" are equivalent to standing in the sun for two seconds (about the normal exposure for an outdoor wet plate portrait). Unless you know something I don't?

It's not the length of the exposure; it's the intensity of the lights themselves (https://www.aptechnologies.co.uk/uv-led-eye-safety/support/light-emitting-diodes/uv-led-eye-safety) that is problematic. I should have phrased that more precisely.

Mark Sawyer
1-Mar-2017, 18:28
I think it's not so much the intensity of the UV, which would be similar to or less than the sun's. It's the absence of white light to discourage one from staring directly into them. I'd agree with your original assessment, and stay away from LED's for just that reason.

seezee
2-Mar-2017, 17:21
I think it's not so much the intensity of the UV, which would be similar to or less than the sun's. It's the absence of white light to discourage one from staring directly into them. I'd agree with your original assessment, and stay away from LED's for just that reason.

I think you may be onto something. I probably confused the logic for avoiding them, but UV LEDs (and fluorescents) are potentially dangerous to one's health, hence the stern warnings from the manufacturers and the goggles issued at tanning salons.

photojeff3200
2-Mar-2017, 20:10
I just finished a project where I shot 140 wet plate portraits in the studio. I never shoot indoors, always out in the sun, so I wanted to invest the least amount of money in lights. I bought two high powered LED floodlights at 6500K. These lights illuminated half a block in the promotional images however when I set them up they really weak and I quickly realized I needed a lot more light. I then built two sets of 4 foot florescent lights with 6 bulbs on each side for a total of 12 additional lights. My exposure was still 6 seconds at 4.5.

Mark Sawyer
3-Mar-2017, 11:47
The thing to understand about LED's is that they can emit a very pure, narrow wavelength. I have a bright cluster of 48 red LED's that I can shine into my silver bath at close range to inspect the plate as I pull it (watching for little floaties) without any fear of fogging because the wavelength emission is so narrow and pure. When working with high-power UV LED's, that means you can have a lot of intensity in the UV wavelength, which won't be very bright visually, yet could fry your eyes.

My original response to Seezee was based on the thought, "well, it's no more UV-intense than the sun, which we deal with every day". But imagine if the sun was visually so dim that we could comfortably stare directly into it for long periods, yet it was still putting out the same volume of eye-damaging UV light. That's what you're dealing with when you use those pure UV LED's...

All things considered, I'd stay away from the UV LED's.

knuf
13-Mar-2017, 14:43
1. UV portion is almost useless - won`t pass through glass below 350nm. you need massive blue portion instead

2. hybrid (custom wavelenghts) LED modules are best for this . I use hybrid aquarium LEDs with 5 channels (10000K+15000K+420nm+445nm+455nm) and can get to 1s@f5.6 with OWH

with such short exposure time it would be possible to add two UV-channels - 360nm / 380nm or 380nm/400nm in place of those two white channels. and still you can light up the channels individually - blue/whites for setting things up and then blue+UV for exposure

chassis
14-Mar-2017, 17:17
What kind of studio strobe power is needed for an f/8 or f/11 exposure at head and shoulders portrait distance? Would 3600 W-s do the trick?

I have never done wet plate.

janosch simon
15-Mar-2017, 04:53
hey there i have a Hensel 3000ws head and for head and shoulder portrait with powersetting of p7.5 of p10 with aero ektar at f2.5 i got a good exposure why you want to shoot portrait f8 or f11? with p10 setting of my flash you feel the head and its VERY bright :-)

cheers janosch

chassis
16-Mar-2017, 08:11
The interest in f/8 and f/11 exposure is more easily attained critical sharpness due to a bit more DOF.

janosch simon
17-Mar-2017, 01:51
hm to me thats the beauty of LF :-) that razor thin DOF :-)