Studio lighting using LF IR film (NSFW)

[StoneNYC]

So the other day I was working with a model, and decided to try out some IR film on a shot I was doing, I knew that to get a decent image inside with EFKE IR 820 I would need to let the exposure go for about 3 minutes, which was a long time. So I decided to try popping the strobes, I decided a good test would be 5 pops at full, my guesstimate was just about right.

My equipment is Profoto brand 1200 ws power pack (7B) and normal ProHead with a single silk diffusion layer in a small wafer brand softbox/lightbank.

So the total output was 1200ws.

As I understand it, Profoto tends to throw off a bit more IR and UV light with their strobes than some other brands, and you can increase that by removing the glass protection dome (which I did not do).

The light was 3-6 feet from the models body.

Because this was mostly a test, I wanted to see how the outside natural IR light balanced with the strobe light (hence the harsh directional light).

f/22 and R72 filter at however long it took to pop 5 full pops and recycling between which was about 15 secons total.



In contrast here is a non-strobe image which took 3 minutes at f/22 with R72 filter.



So cumulatively we are talking 1200ws X 5 = 6000ws required for a decent exposure. Sadly I didn't pick up that 4800ws pack I could have a few years ago, and I just sold my 2400ws pack so multiple pops is my only option.

Has anyone else attempted this with other strobe brands and found different results with their brand?

Or found any other techniques to expose IR film? Because of the LF aspect, and subject matter, getting a decent DOF for me means smaller apertures so f/22 is more the range I'm comfortable with. The smaller formats I could go as low as f/4 and not have to worry too much, possibly handheld (like with the Mamiya7 where you have a separate viewfinder) but with LF the light control gets a little more tenuous.

Also, has anyone worker with HIE that's a little more sensitive to IR or Rollie IR400/200 sheet film that's a lot less sensitive to IR? I would be particularly interested in the latter as that's all we will have left once the stocks of EFKE are all gone.

I feel like this is a good start to the studio lighting forum that could benefit others in this unique niche partial to LF issues.

Thanks!

[Tracy Storer]

I have not done much with IR, but when I did experiment several years ago(small format) I found various Lowell hot lights to be pretty effective. (probably a much higher proportion of IR to visible than strobes.)

[jp]

Your strobe image seems to have less IR; perhaps it's just overpowering the filter. Your non strobe image exhibits more IR character; blood vessels visible in the shoulder, paler skin. (Things I've noted in my limited experiences photographing people in IR with my converted DSLR)

It's not really a genre I'm working in, but this looked like an interesting class. http://www.mainemedia.edu/workshops/...ed-female-form

[StoneNYC]

Your strobe image seems to have less IR; perhaps it's just overpowering the filter. Your non strobe image exhibits more IR character; blood vessels visible in the shoulder, paler skin. (Things I've noted in my limited experiences photographing people in IR with my converted DSLR)

It's not really a genre I'm working in, but this looked like an interesting class. http://www.mainemedia.edu/workshops/...ed-female-form

I don't know if it can "overpower" the filter, the filter FILTERS a certain wavelength of light, so it's my understanding that the light would be blocked, wouldn't it?

I can see the high end of the nm range maybe passing though and overpowering the scene or whatnot, good thought, you're right there aren't many veins.

I shot a non-IR filtered 8x10 sheet of the EFKE IR820 yesterday with a model, so I'm curious if any IR effects will show up.

I did shoot one IR 8x10 sheet with the filter but I didn't use any lighting (but the sun) so that doesn't pertain to this thread.

Does anyone else know about the IR releasing light of certain strobe producing companies? Or if removing the glass protection dome would increase the IR significantly in the Profoto strobes?