Questions about lighting for wet plate photo (studio portrait)

[AgX]

Geeze that's a little bit over the top. In twenty years of using Profoto and 13 years of working with other pro photographers, I've never once seen or even heard of a flash tube exploding. Has anyone here using strobes ever seen a flash tube explode?

I explicetedly said that I see no reason for a flashtube to explode on its own. If being apt for the respective generator charge.

A different thing are bare halogen lamps!

I experienced a lamp exploding in a luminaire I held in hand. Fire and blood all around. My blood.

 

[Eric Hiss]

I think that the bulbs in old style luminaire are different from modern modeling lights in strobes. And in the case one is worried about that 'exploding' you could always turn off the modeling light when the cover is off for doing wet plate or whatever.

 

[MattKing]

I took AgX's comment to be a caution, not a denial.
If you take the covers off for a particular use, consider replacing them.
I have seen flash tubes and halogen lights explode, but I agree that it doesn't happen regularly, except when working in wet conditions.

 

[Arthurwg]

You might consider renting 4800 w/s strobes for your portrait sessions. And have you considered natural light outdoors? I think most subjects can sit still for 5 sec. exposures.

 

[awty]

Speaking of lighting has any one got any experience with one of these? Lund photographics Led UV light

LED Lamp, Studio Blue

We're approaching studio lighting from a completely different perspective; one that's specifically made for collodion and alt pro photography.

www.lundphotographics.com

I have one, haven't tried it yet, guess its too slow for people unless I sedate them first.

 

[AgX]

Thank you, for hinting at that light anyway.


(Maybe San can add a new forum "Medication"....)

 

[koraks]

guess its too slow for people unless I sedate them first.

Apart from that, I'd be uncomfortable asking my models to look into bright UV light. A few seconds likely won't hurt, but from an ethical perspective, it doesn't feel right. I don't like contributing to someone's cateract.

 

[awty]

Apart from that, I'd be uncomfortable asking my models to look into bright UV light. A few seconds likely won't hurt, but from an ethical perspective, it doesn't feel right. I don't like contributing to someone's cateract.

Compared to the sun it's quite pleasant.
With a 300 watt uv lamp and the UV LED, I can get f8 @10 secs.
I've had many decades of UV eye abuse and no cataract problems....yet.

 

[koraks]

Compared to the sun it's quite pleasant

No, not necessarily. While sun protection is also important, the difference between a UV source and the sun is that the pupil will contract in bright sunlight, protecting at least part of the eye from UV damage (so it won't protect against conjunctivitis / 'Klieg eye'). Since a UV source only emits a small fragment of its light in the visible spectrum, the pupil response is less pronounced, resulting in a much larger risk for e.g. retinal damage.

I've had many decades of UV eye abuse and no cataract problems....yet.

I had an aunt who smoked a pack a day and lived to the ripe age of 90...as with many things, you only know how much to appreciate it when it starts to fail. Moreover, like I said: it's not so much the photographer; they make a deliberate choice. It's the model and the ethics related to them.

 

[awty]

No, not necessarily. While sun protection is also important, the difference between a UV source and the sun is that the pupil will contract in bright sunlight, protecting at least part of the eye from UV damage (so it won't protect against conjunctivitis / 'Klieg eye'). Since a UV source only emits a small fragment of its light in the visible spectrum, the pupil response is less pronounced, resulting in a much larger risk for e.g. retinal damage.



I had an aunt who smoked a pack a day and lived to the ripe age of 90...as with many things, you only know how much to appreciate it when it starts to fail. Moreover, like I said: it's not so much the photographer; they make a deliberate choice. It's the model and the ethics related to them.

Only in your imagination.

 

[awty]

3 secs @ F9 using 2x 100watt uv LED spot lights that cost $60 each (same as the types they use in night clubs etc ). Have lights connected to a enlarger timer triggered by tow. No lag, open shutter with bulb in dimly red lit room just before and close shutter once lights go out.
They are cheap not very bright compared to other UV's Ive been using but very effective
Should be able to get 1.5secs with F5.6, could light the room just before to get eyes better accustomed.
Just need to better set the lights and fix all the other wet plate variables.

 

[ludwik]

Collodion is sensitive to UV and visible blue spectrum. I wonder why people bother to use thousands of Ws flash lights if collodion will "see" only a fraction of it and flash itself is only 1/8000th of a second or so...
blue LED light - like royal blue (450-465) + Ice blue (470-475nm) should be well enough for collodion and its not a UV so its safe to use. You could probably get away with 200-300W and time as long as 1/125s

 

[Pieter12]

Geeze that's a little bit over the top. In twenty years of using Profoto and 13 years of working with other pro photographers, I've never once seen or even heard of a flash tube exploding. Has anyone here using strobes ever seen a flash tube or modeling light explode? I mean if you throw cold water at it or knock the thing over that's different, but just explode all on its own? The great thing about tin type / wet plate is that you just need one pop every 10 minutes or so at most. And Halogen bulbs the same - never seen one blow. You can buy non UV coated covers for the profoto heads if you want a cover. I suspect the real reason why Profoto puts covers over the flash tubes is mostly to make a slightly softer and even light. I would not advise using your flash heads naked long-term, just saying it really made a difference for wet plate work.

My Hensel glass domes are clear, and available coated or uncoated. They also have large holes for ventilation, so I don't think they are designed to protect from an exploding lamp. And I have never heard of a halogen bulb exploding. They are (or at least have been) in use for domestic and automotive purposes for years and years now. I think the bulb glass might crack from the heat produced by the bulb if it has been handled and skin oil has been transferred to the glass.

 

[Pieter12]

When Chuck Close made his Daguerrotypes, he and Jerry Spagnoli devised a strobe that produces 30,000 watt-seconds of illumination, which is enough to make an instantaneous exposure. The level of light is so bright it can redden the sitter’s skin and even singe hair.

 

[koraks]

Collodion is sensitive to UV and visible blue spectrum. I wonder why people bother to use thousands of Ws flash lights if collodion will "see" only a fraction of it and flash itself is only 1/8000th of a second or so...

Because flash tends to emit quite a bit of UV, which is very useful for collodion, and the short exposure makes it very suitable for portraiture.

blue LED light - like royal blue (450-465) + Ice blue (470-475nm) should be well enough for collodion and its not a UV so its safe to use. You could probably get away with 200-300W and time as long as 1/125s

No you won't. Go on and try it. You'll be mightily disappointed. Wet plate sensitivity is pretty low to begin with, especially so in the visual spectrum, even on the blue side.

If you want to figure out why people are doing it the way they're doing it, you have no choice but to (1) take their word for it or (2) pick up collodion photography yourself.

 

[Eric Hiss]

I can't remember if I posted this or not, but I've got a C-700 Sekonic spectrum analyzer and I measured all of my flash units and flash heads in the studio - they are all Profoto but some were acute heads and some pro heads and I know a few had bulb replacements -- all came to me used. Obviously the coated cover glass reduced the UV, a few didn't have UV coatings but still blocked some of the UV so we went bare. Anyhow there were two that emitted significantly more UV so we used those. We worked mostly with f/6.8 to f/8 and had no problems with getting good exposures with the flash units. I later lent the strobes to my friend Jenny Sampson who used them for a few other studio projects. No problems, everything worked well. It seems that possibly there are some flash tubes which are uncoated and some which are coated. I'm betting that the lower priced strobes will have uncoated tubes and cover glass. The Blue LED lamps seem like a possible solution but looking at the spectrum - it's just a thin peak - like a specific wavelength so not much area and therefore the exposure times will be pretty long unless you have a ton of them.

 

[Nicholas Lindan]

Sounds like a job opportunity for models that have already had cataract surgery.

 

[Pieter12]

Sounds like a job opportunity for models that have already had cataract surgery.

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