I have 3, 500 watt, Profoto strobes--will those be powerful enough to bring down the exposure time much for wet plate photography? What are other people on here using?
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I have 3, 500 watt, Profoto strobes--will those be powerful enough to bring down the exposure time much for wet plate photography? What are other people on here using?
I don't have such high power Profoto strobes.
It said that Profoto flashes used crystal(not glasses) for its lights according to the manufacturer instruction. Crystal stops the UV light.
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Probably not. We used two Profoto Acute 2 packs in our tintype studio, at 2400 watts each. They were firing through a huge softbox, so it might be that three bare strobes ganged together would be enough.
Set your light meter to ISO 1 and fire your strobes and see what you get.
Lots of missing information: How fast is your lens? what kind of reflectors or modifiers are you using? How close are the strobes to the subject?
There are lots of posts on this. Do a search.
What light meter do you use that reads ISO 1?Quote:
Originally Posted by vdonovan2000
In theory, a less powerful monolight could compare to an Acute 2 pack, since power is lost between the power pack and the head. I don't do wet plate, but I've shot portraits on Ilford Direct Positive Paper rated at ISO 3 with a Symmar 180mm f/5.6 stopped down to f/6.7 using a single White Lightning X3200 about 3ft from the subject at full power (and a second one as fill at 1/2 power) for fill--both in shoot-through umbrellas.Quote:
Originally Posted by vdonovan2000
If the OP has access to a lens that can open up to at least f/3.5 (maybe a Xenotar 135mm or a fast Xenar/Tessar) and can get all three strobes close enough, I'd say getting an ISO 1 reading should be possible. If he has D1's, even better. They're much more efficient than than my White Lightnings.
If you remove the protective globes that cover the actual strobe bulb it will increase the UV power, Profoto strobes produce more UV than other strobes, that's why the protective globe has a UV blocker added. Just don't break the bulb, obviously with the globe removed the bulb is more susceptible to getting damaged.
I don't do WP but from what I understand you're going to need a LOT more power, more like 6 individual 2400 WS bulbs on separate 2400 power packs or split on 3 4800 power packs to get good power at a normal shutter speed. If on the other hand you're happy with a few seconds you could probably pop the strobes a few times in a row to stack the power.
You'll need the lights to be close to the face, like a few feet probably.
Normal light meters don't measure UV light so they aren't entirely helpful but in general you can assume a correlation that might work OK for metering purposes once you've done a few test plates, the higher end sekonic will stack strobe pops for you and add them up, not sure about all meters.
If I had actual WP experience I would be able to give you solid numbers.
I do recommend that you do a search, but here is what I used.
I used two Speedotron 4800ws boxes with a single 9600ws head. These are not uv coated bulbs, but I'm not sure that makes a discernible difference. I used a 22" beauty dish, that was about 4 feet from the individual. With glass, depending on the salts, age, as well as the subject, I shot between F8 and F11. As I recall, aluminum was a little faster, and negatives were significantly slower. I think the last negative I shot was at F5.6. I noticed I could get an extra two stops if I used a highly reflective 16" sports reflector but these are not made for portraiture and make the subject look really blasted out. Shooting through an umbrella or soft box pulled way too much light, so I never bothered.
I will say that 9600ws is a little much for human subjects. It feels like a hot blast of air. I also don't think that WP looks very good with strobe. The highlights very quickly block up, and it takes the right salts, a lot of work and precision to get the right exposure.
Attachment 148832I just made some measurements of Norman electronic flash equipment with wet plate photography in mind. First up was a Norman bi-tube head at 4800WS in a Norman 22" Beauty Dish reflector. The distance from reflector to the flash meter was 8'. The meter was set to ISO 1, and the indicated exposure was F45
Next I measured the output of a 10" Norman-converted Bardwell-McAlister Fresnel spot/flood keg light. On the full flood setting, 2400WS produced an ISO 1 exposure of F45 2/3. Surprisingly, the output did not vary significantly as the beam was narrowed from flood to spot, dropping to F45 at the spot setting.
Richard Pippin plans to visit me with a wet plate outfit next week and we will have more to report after some real world testing.