590nm IR-Pass Filter and Colour Film

For the sake of experimentation and maybe getting some novel, interesting results out of it; is there any colour film out there that has especially good spectral sensitivity? Sensitive beyond the visible spectrum, with which I could use a 590nm IR-pass filter? I love the look of 590nm, but I don't love the cost of converting a digital camera, nor digital images, nor the cost of IR color films. I understand exposure times would be considerably longer, but is this even worth exploring? Taking a quick look at Portra 400 charts, there seems to be some sensitivity for magenta and cyan dyes at 590nm, if I understand correctly.

If anyone has prior experience with such a thing, or can offer insight, that'd be greatly appreciated!

I've not heard of colour films, but I have heard that some colour papers are IR sensitive...

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Originally Posted by Andrew O'Neill

I've not heard of colour films, but I have heard that some colour papers are IR sensitive...

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Any idea where I could find more about this? I might look into that...

I think it was the light jet type C papers, but I could be remembering wrong...

Steve K

590nm is orange, so yeah, all panchromatic and color films have response beyond that point. Portra 400 drops off sharply and does nothing at about 670nm though, so no IR response at all. In fact, I'd say that any response beyond 690nm would be undesirable for any color film (used for its intended purpose) as it would introduce 'false' colors. So logically, it's a dead-end street. Not to mention that it would require additional dyes in order to get sensitivity beyond visible red, which would be an illogical additional R&D step in the development of a visible light color film.

But wasn't there (once upon a time) a Kodak IR-sensitive color film? The Kodak EIR stuff?

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Originally Posted by Bipin

For the sake of experimentation and maybe getting some novel, interesting results out of it; is there any colour film out there that has especially good spectral sensitivity? Sensitive beyond the visible spectrum, with which I could use a 590nm IR-pass filter? I love the look of 590nm, but I don't love the cost of converting a digital camera, nor digital images, nor the cost of IR color films. I understand exposure times would be considerably longer, but is this even worth exploring? Taking a quick look at Portra 400 charts, there seems to be some sensitivity for magenta and cyan dyes at 590nm, if I understand correctly.

If anyone has prior experience with such a thing, or can offer insight, that'd be greatly appreciated!

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Aerochrome !!! You can get it expired at auction. Problem that i sheets it's hard to find and expensive, but still a possibility for MF.

The red sensitive layer alone it has extended IR sensitivity, vegetables do not reflect much red, but do reflect a lot of IR, being the (common) chlorophyll reflection peak around 800nm. In that way millitary surveillance could see the forest in red and big camouflage covering armor etc in green, but it was learned that natural branches still worked. Also it was used for scientific things.

https://www.flickr.com/photos/peterd...in/dateposted/

https://www.flickr.com/photos/peterd...in/dateposted/

https://www.thephoblographer.com/201...chrome-purple/
https://filmphotographyproject.com/t...infrared-film/

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With a 590 filter you would see the colors you allow to pass:

https://upload.wikimedia.org/wikiped...SMJ2_E.svg.png

https://en.wikipedia.org/wiki/Color

koraks, and everyone, EIR (Ektachrome Infrared) was an E-6 film made in 35mm. I doubt if Kodak made it in 120 or sheet formats, but I never had a need for those. Aerochrome Infrared (2443?) was a different film, supplied in long rolls for reconnaissance and scientific use. It used a different, older, and more complex process called EA-5, similar to the old C-22 color-neg process. I've been out of that loop for a few years now so my memory (for things that were peripheral at the time) is imperfect. But I suspect that long-roll Aerochrome is gone (replaced by multi-spectral remote sensing), like the E-6 EIR. But there might be some still out there.

I don't remember exactly but wasn't EIR E-4 process???

I think you had to send it out to a lab that only did E-4 once in a while, and wait for the next processing run to come up (I think it was every few months) once they had a big enough run to make it worth their while...

But this is very old info in my head...

Steve K

You could take a look at Ektar 100 and, to a lesser degree, Portra 800. The Ektar is the subject of some debate among astrophotographers as a material that might be able to pick out the 653.6 nanometer wave length of hydrogen-alpha emissions. I haven't seen any results myself; nobody yet seems sure of it's reciprocity characteristics.

In more conventional uses, it has a reputation for occasionally blocking up deep reds under certain light conditions. Available in sheets or rolls.

Derek