I.R in 4x5

[Robert Hall]

This is not exactly true, Scott. Chlorophyll has little to do with reflectivity of IR. It is the inner cell wall which reflects the light. The amount of reflectivity has to do with the size of the cell and the systemic pressure of the cells. This is the same reason why we see the deeper layers of skin as the reflected surface with IR shots.

This was proven by putting a leaf in a vacum, IIRC, and it became transparent under IR. I know if Helen gets ahold of this thread she could probably spread some light on the subject.

Our skin (epidermis) has similar properties to the leaves. We have lots of dead skin cells on the upper layers, they reflect blue really well. Take a look at skin shot under blue light the take a look at the same shot in IR or deep red. The skin appears smoother with red light as it penetrates the damaged or dead layers of skin.

 

[Shmoo]

I use a Zone VI field camera and was thinking of getting me a box of EFKE and a Lee 87C filter. Anyone have any advice or know of any pitfalls I should be aware of before I embark on the quest?

I think the Rollei IR works similarly to the Macophot. I haven't tried the Efke yet, but the 87 filter is a good choice. It takes about 1 more stop exposure than an 89b filter but it gives you a less "gimmicky" look. Here's one with the 87 filter:


(there was a url link here which no longer exists)

 

[David William White]

Actually, the IR effect has nothing to do with emitted light, but rather reflected light. To see how this works, try taking a photograph of the same subject under tungsten illumination and fluorescent illumination, using an 87 IR filter, where both light sources provide an identical light meter reading at the subject location. Tungsten lights are rich in infrared; fluorescent is lacking in IR. Your subject will look quite different under the two light sources; the fluorescent-lit shot will appear significantly underexposed, if it records an image at all.

Knowledgeable and coherent. So to summarize the risk of fogging in film holders shooting outdoors, I think we can summarize and say:

1) Foliage seems natural when shot on IR unfiltered. Only when visible is blocked do we see an effect -- and then only when we extend exposure many stops. Therefore reflected IR is only a small fraction of the total reflected light from foliage.

2) Skies contain almost no IR (because they appear black).

3) BobNewYork is also correct that HOT bodies emit tons of IR, and these can certainly fog IR film, but these are not normally present in a landscape scene.

Can we safely say that IR film is no more prone to fogging when shooting a typical landscape, and that the fogging is probably do to VISIBLE light?

If not, what are we missing?

D.

 

[BobNewYork]

Shmoo: That's what I'm looking for - Thanks a lot.

David: Hear you. However, if fogging is due to visible light why the additional precautions re loading, camera type etc with IR film? Surely, if it were just the visible light then all films should be subject to the same precautions.:confused:

 

[Ole]

3) BobNewYork is also correct that HOT bodies emit tons of IR, and these can certainly fog IR film, but these are not normally present in a landscape scene.

Only very hot bodies. At least red hot, to be precise. Just before they glow visibly red they will glow infrared, but very weakly compared to what they do when white hot.

Things that hot are not common in landscapes, unless you're shooting volcanic eruptions or forest fires.

Can we safely say that IR film is no more prone to fogging when shooting a typical landscape, and that the fogging is probably do to VISIBLE light?

Sunlight is also rich in IR, and a light leak that leaks only in IR won't be visible to anything but IR film. Small insignificant light leaks also become significant when you expose for several seconds in strong light through a dark filter - remember that the light leaks are unfiltered.

 

[David William White]

Shmoo: That's what I'm looking for - Thanks a lot.

David: Hear you. However, if fogging is due to visible light why the additional precautions re loading, camera type etc with IR film? Surely, if it were just the visible light then all films should be subject to the same precautions.:confused:

True, my line of reasoning is not yet coherent. We need to hear from people who've experienced light leaks with roll film: all our 4x5 film is loaded in complete darkness!

 

[PhotoJim]

Let's analogize it this way.

35mm infrared film can fog if handled in light. There will be leaks through the felt light trap. This is particularly true with Kodak HIE, which has sensitivity further into the infrared than other infrared films tend to have.

Clearly the felt trap blocks visible light but not infrared.

If sheet film holders have this same issue, then there will be fogging of the sheet of film while in the holder.

Similarly, if view cameras have similar issues, there will be fogging of the image while the dark slide is removed from the holder.

I've never shot infrared film in a sheet film camera so I can't tell you the real-life effects of this, but it wouldn't surprise me if there are some.

 

[Ole]

35mm infrared film can fog if handled in light.

Right.

There will be leaks through the felt light trap. This is particularly true with Kodak HIE, which has sensitivity further into the infrared than other infrared films tend to have.

Clearly the felt trap blocks visible light but not infrared.

Wrong.

What makes Kodak HIE fog more easily than other films is a combination of high sensitivity and clear base. The clear base makes the protrusing end of the film act like an optic fiber, piping light in and fogging the film even all the way to the core.

Other films with clear base also fog easily for the same reason, but since the sensitivity is lower they don't tend to fog quit eas badly from a few seconds in daylight.

 

[Murray@uptowngallery]

I have shot half a roll of 120 (4 @ 6x9) then repeated the exposures and had half a roll developed then made adjustments (or just diagnosed how far off it was & didn't bother developing the 2nd half).

Of course, that only works when you are doing a whole roll in the same location not horribly inconvenient to repeat shots...mine were just test shots.

Murray

 

[David William White]

Been thinking about trying some IR for a few years now and just never got around to it. I've admired those images that it works for - and detested those where the IR effect is just plain gimmicky.

I use a Zone VI field camera and was thinking of getting me a box of EFKE and a Lee 87C filter. Anyone have any advice or know of any pitfalls I should be aware of before I embark on the quest?

Okay, so after all that conjecture, my summation is that if you don't have any light leaks with normal film in your holders, you will be fine with IR film loaded. The only other pitfall with the 87 filter is to rate the film really low and be prepared to go lower. I'm at ISO 1 so far (after half a box) and barely getting enough density to print. Fearlessly go forth, but please let us know how you make out.

D.

 

[BobNewYork]

I will indeed. Thanks a lot to all. I'm just headed out to buy a calendar to time my exposures!!!

 

[JBrunner]

Okay, so after all that conjecture, my summation is that if you don't have any light leaks with normal film in your holders, you will be fine with IR film loaded.

D.

No. Some holders that are fine for "normal" film leak IR. Normal film isn't very sensitive to that spectrum, but IR film may fog in some holders.

 

[David William White]

Them's experimentin' words!

 

[JBrunner]

Them's experimentin' words!

Precisly, test with one sheet. If it works, you can be fairly sure that identical holders with identical dark slides will be ok. The modern "five bump" Fidelity holders are ok.

 

[Schafphoto]

I have a box ready to load of the 4x5 Efke, i tried the 35mm and 120 size and eventually got to ASAs around 1/2 and 3/4 or ASA 1 with a +one stop push processing from my normal T-maxRS developer time. I have samples up on my Flickr site that I shot with 29 dark red (little/no IR effect) and with a 092 B+W filter and a Cokin SFX200 cutoff filter (much better IR effect). The Efke even seems to glow and halate a little, even though it has an AH layer. I was surprised at how HIE-like it looked. But 4 second exposures at f8 in bright sun will take some getting used to. If you shoot a lot of flowing waterfalls, this film will be perfect... no ND needed.

-Schaf
http://www.flickr.com/photos/schafphoto

 

[Ole]

Dead Link Removed
Maco IR 820c, Lee IR gel filter, Zeiss Planar 135mm f:3.5

I rather like it...

 

[Cor]

Right.



Wrong.

What makes Kodak HIE fog more easily than other films is a combination of high sensitivity and clear base. The clear base makes the protruding end of the film act like an optic fiber, piping light in and fogging the film even all the way to the core.

Other films with clear base also fog easily for the same reason, but since the sensitivity is lower they don't tend to fog quit eas badly from a few seconds in daylight.

..perhaps one more thing to add: Kodak HIE has no anti halo layer (hence the halo's around bright objects against a dark sky), whereas other films with a clear base (TechPan) AFAIK do have a AH layer..

Best,

Cor

 

[Robert Hall]

Ole, we did some testing a few years back and found that some felt traps on cartridges did in fact reflect IR and some absorb. IIRC one gent was able to eliminate his IR fogging substantially with the right kind of felt traps.

I fully agree with you on the clear base and would suggest that one keeps the film leader out of the light due to the light piping.