4x5 Kodak HSI: any special considerations?

[23rdhourphoto]

Hey everyone,

I've come to this forum because I can't find any accounts online of people shooting Kodak HSI in large formats, and I've just bought a box of 25 sheets (expired '01, sealed, allegedly cold stored its whole life) from eBay. I've been shooting 4x5 for a few months now with good results; do I need to be wary of IR specifically in my film holders? Have any of you had issues specific to this film? I've read the datasheet and it suggests subdued light; what does this mean practically in the field?

On another note, what subject matter do you like to shoot for LF infrared? I'm considering using my pinhole board for some landscape work, and obviously foliage is great, but have you ever tried Portraits?

Thank you for your guidance; I'm relatively new in LF compared to most of you and look forward to your advice.

[Doremus Scudder]

Making sure your bellows are opaque to infrared is a consideration. Some bellows aren't and will fog the film. Most main-stream filmholders should be fine, but check darkslide opacity to infrared if in doubt.

You'll have to figure out the focus shift too. There are likely charts for how much correction and which way for various focal lengths and subject-to-film distances online somewhere. Maybe someone will contribute here with one.

Load and unload (and develop) the film in total darkness just like other LF film. The "subdued light" recommendation is for handling roll film.

Best,

Doremus

[paulbarden]

Kodak HIE infrared sheet film of that age requires special handling: do NOT touch the emulsion side of the sheets with anything but cotton gloves, or there's a significant chance you'll leave marks (I speak from experience with 8x10 sheets of HIE)
Doremus's suggestions are good ones. Both my Intrepid bellows and the Vinyl bellows on my Deardorff are somewhat permeable to IR radiation, so it will be in your best interest to cover the bellows with your dark cloth for added protection. Film holders should be safe to use, but you should pack them into dark bags (I use the black plastic bags from silver gelatin paper packages) and only take them out when you are 100% ready to insert the holder in the camera. Always shade the holder with your body as you take the holder from the dark bag and move it to the camera (presumably under the dark cloth)
I also found there is some degree of IR penetration through the wood lens board on my Deardorff when shooting HIE, and so I wrap the lens board with a layer of aluminum foil to block IR. Its tedious, but it does resolve the issue. A metal lens board won't have this problem, of course.
As Doremus said, you must load film holders (and process the film!) in TOTAL darkness. I recommend doing it after dark to avoid any light leaks your darkroom (or whatever you have available for film loading) might have.

Kodak HIE has sensitivity quite a bit beyond the IR range of modern IR films, and so it responds spectacularly to the opaque IR filters, like the R72. Using an R72 will result in much longer exposure times (think multiple seconds at f22 in bright sunlight), and the filter is visually opaque, so you will have to remove the filter to compose, and make sure it goes back on the lens before you make an exposure. This hassle can be avoided by using the more common #25 Red (most photographers already own one of these) which you can see through, thus avoiding taking it off and back on the lens. However, the compromise is that a #25 Red filter isn't going to give you the same dramatic results compared to an R72.

Using a pinhole rather than a lens may produce disappointing results. I found that light coming through a pinhole is diffuse enough that it renders a very soft image on Kodak HIE (the Rollei IR film is better in this respect), so don't waste too much of this precious resource experimenting with things like a pinhole. In my opinion you will get much better results if you stick to a lens. (I did a few experiments with a cookie tin pinhole camera back in 2017, and you can see one of the more acceptable images here: https://flic.kr/p/ShxwxD )

You do also need to pay some attention to focus adjustments for IR radiation: it doesn't focus on the same plane as visible light. You can get around making any adjustments by using a very small aperture, which will generally insure sufficient sharpness. I'm talking f22 or smaller (on large format). I forget the formula for focus adjustment, but its a tiny amount, shifting the lens slightly closer to the subject. As I say, you can avoid this entirely if you work with small apertures.

[reddesert]

I never used Kodak HS IR in 4x5, only in 35mm. Even in 35mm, you are supposed to open the film can and load the camera in total darkness. Following the principle of having two layers of prevention, even if neither is guaranteed perfect, I loaded the camera in a changing bag in a darkish room (not literally a photographic darkroom), and didn't have any light leaks.

The IR film is very sensitive to light leaks; I think it's also sensitive to light piping through the substrate, and of course it doesn't have an anti-halation layer. I would try to keep film holders (and the camera when a holder is inserted) in subdued light as much as possible, and follow the precautions Paul suggests. Try to never let sun fall directly on the holders, light trap, bellows, etc, using the darkcloth and possibly a sheet of aluminum foil to cover as much as you can.

IR focusing marks are important for wide apertures common in 35mm, but maybe less critical at small LF apertures. For IR light, the focal length of a lens is always a little longer than for visible. One rule of thumb is that the focal length increases by about 1/400 - this is a crude approximation since it depends on the lens design. For say a 210mm lens that means moving the lens forward by just 210/400 = 0.5mm (for distant subjects), and if you're shooting at f/22 your depth of focus might be ~2.2mm, so the IR focus shift could be small compared to the total depth of focus. Obviously, this is guesswork, but it's a starting point.

[23rdhourphoto]

Thank you all for the advice. The most important bits of info I have seen are:

-Load film into holders at night in the dark. I use a changing bag, so this will add an extra layer of protection.

-Don't touch film with bare hands, only gloves. Question: do nitrile gloves work, or do they have to specifically be cotton?

-Film loaders are IR-Opaque, but bellows, not necessarily. I have just replaced my bellows on my Tachihara with good thick cloth, so hopefully they will be, but I'll do the half-sheet fog exposure test to know for sure. Failing this, it's aluminum foil to the rescue. I have metal lens boards so that shouldn't be an issue at least.

-Shift focus, potentially, and shoot at f/22 or so when possible, using IR720 or red filters. I have a Red 25 and a 720nm filter, so now all I need is a step-up ring to fit my 150mm lens.

-Never let the holders see direct sunlight. Dark bag the holders until loading time, then leave the dark cloth over the holder and bellows for exposure.

Thank you all, and if you have any more advice, I'm all ears!

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