False color IR with Harman Phoenix?

Yobo57 · Jun 22, 2025

I noticed Harman Phoenix 200 has extended red sensitivity past 700nm and a relatively high peak at around the 665-685 range.

Theoretically, with about a 680nm filter or something like a ZWB3 filter, would it be possible to take false color infrared photos with this film stock? Maybe even 720nm and long exposure times?
The scans would definitely need to be white balanced afterwords.

I know the graphs is for tungsten, not sure how much this affects the values for daylight or if it’s negligible.

What do you think, is it worth a shot to try?

Andrew O'Neill · Jun 23, 2025

Oooooh! I'm very much intrigued!

dcy · Jun 23, 2025

Yobo57 said:
What do you think, is it worth a shot to try?

Please, do try it. What do you have to lose? You could sacrifice 1/3 of a 35mm roll and take 12 shots at +1 stop increments. With 12 stops of range, you'd have a pretty decent chance at either finding an exposure that works, or proving that it doesn't work. Pick a scene that's likely to look good in IR (lots of trees, sunny day, sun behind you).

Do you already have a filter?

koraks · Jun 23, 2025

Yobo57 said:
Theoretically, with about a 680nm filter or something like a ZWB3 filter, would it be possible to take false color infrared photos with this film stock?

No. What you could do is use a 680nm filter and obtain a totally red image, but it won't be anything resembling a false color 'IR' photograph. The red exposure will only create cyan dye, so there will only be one color in the final image. It will not be much different than any other color film (negative or positive) shot through a deep red filter.

For false color IR you need wavelength shifting; so longer wavelength captured light needs to be converted into a color that corresponds to a different wavelength in the spectrum. That's what e.g. Kodak HIE did. Basically, it would capture IR and show it as red, capture red and show it as green etc. That's a bit of a simplistic way to put it, but it's the basic principle of how the stuff worked. It relies on the fact that the sensitizing dye (which determines the layer's spectral sensitivity) and the dye coupler (which controls the color of the dye generated during processing) are distinct aspects of the emulsion and can be chosen in separation from each other. Harman Phoenix is no different from any other regular color negative film in this regard.

khh · Jun 23, 2025

What you could probably do is shoot it like a trichrome exposure, but with each exposure on the same frame, and substitute the red filter for a 680nm or higher filter to capture more infrared than ordinary red. It still wouldn't look like aerochrome, though. Unless I'm completely messing up the color model in my head, it should shift folliage towards a more yellow hue.

koraks · Jun 23, 2025

khh said:
Unless I'm completely messing up the color model in my head, it should shift folliage towards a more yellow hue.

If you shoot through a red filter, what part of the film is going to create yellow or magenta dye? Or do you mean a regular exposure without filter followed by one through a deep red filter? Even so, you'd just be creating additional cyan dye (=red in the positive photo). It would just shift the color balance of the entire frame towards red.

dcy · Jun 23, 2025

koraks said:
If you shoot through a red filter, what part of the film is going to create yellow or magenta dye? Or do you mean a regular exposure without filter followed by one through a deep red filter?

Given the reference to trichrome, I think a strict reading of @khh's suggestion is to take three photos with three filters: blue, green, and IR.

I had a similar idea, but @khh's is more interesting. --- My idea was to have blue, green, red, and IR filters and then do digital post-processing to shift the wavelengths. But then I said to myself "What's the point? You can do that with plain IR-sensitive B&W film".

@khh's idea, if I understood it correctly, doesn't require digitally shifting colors. It just deletes red and replaces it with IR.

khh · Jun 23, 2025

dcy said:
Given the reference to trichrome, I think a strict reading of @khh's suggestion is to take three photos with three filters: blue, green, and IR.

I had a similar idea, but @khh's is more interesting. --- My idea was to have blue, green, red, and IR filters and then do digital post-processing to shift the wavelengths. But then I said to myself "What's the point? You can do that with plain IR-sensitive B&W film".

@khh's idea, if I understood it correctly, doesn't require digitally shifting colors. It just deletes red and replaces it with IR.

Yes, exactly. Three exposures of the same frame using a blue filter, a green bandpass filter and an IR filter. You could get the same effect with two exposures using a lowpass filter and a highpass (i.e. IR) filter, but it would probably be even harder to color balance that correctly.

Edit: I mean, as I said you wouldn't end up with aerochrome looking stuff, and what you got probably wouldn't look very good. But it should be a true IR color image.

Yobo57 · Jun 23, 2025

koraks said:
No. What you could do is use a 680nm filter and obtain a totally red image, but it won't be anything resembling a false color 'IR' photograph. The red exposure will only create cyan dye, so there will only be one color in the final image. It will not be much different than any other color film (negative or positive) shot through a deep red filter.

For false color IR you need wavelength shifting; so longer wavelength captured light needs to be converted into a color that corresponds to a different wavelength in the spectrum. That's what e.g. Kodak HIE did. Basically, it would capture IR and show it as red, capture red and show it as green etc. That's a bit of a simplistic way to put it, but it's the basic principle of how the stuff worked. It relies on the fact that the sensitizing dye (which determines the layer's spectral sensitivity) and the dye coupler (which controls the color of the dye generated during processing) are distinct aspects of the emulsion and can be chosen in separation from each other. Harman Phoenix is no different from any other regular color negative film in this regard.

Ok, I guess it wouldn’t work like digital infrared photography? I have a full spectrum camera and the pictures it takes start fully red/pink but with white balancing they turn out with brownish sky and bright teal foliage. My thought process was with the film you could do the same by taking the scans into Lightroom/photoshop and white balancing them for a similar output, but I guess this is not the case?

koraks · Jun 23, 2025

Yobo57 said:
Ok, I guess it wouldn’t work like digital infrared photography?

I'm pretty sure the reason it works so well with digital is that on a typical CMOS sensor, all 3 channels have considerable (but varying) inherent IR sensitivity. On a color film, you only have one layer with some very mild responsivity to IR, so all you'll capture in terms of IR will be red.
Yet, as @khh and @dcy point out above, you could do something with that alright. I think it won't be nearly as strong an effect as you can get with digital, but it may be pretty neat still!

dcy · Jun 23, 2025

Oh... Small iteration on @khh's idea: Take two photos. One with a cyan filter, so it lets blue + green through but blocks red, and another with an IR filter.

Fewer steps, and any movement in the scene would appear only in the IR layer (rendered as red). Blue + green would look normal, with no shift between them. Red is gone, and IR takes its place, but with a smooth texture like what you get when you use ND filters.

The result could be a really interesting, other-worldly look.

dcy · Jun 23, 2025

If you have a camera that can take double exposures, you can do a poor man's aerochrome with a 100% analog process. Take one exposure with a cyan filter and another, much longer exposure with an IR filter.

My camera cannot do double exposures, nor do I have the right filters, but I'd love to see someone try this.

Yobo57 · Jun 23, 2025

dcy said:
If you have a camera that can take double exposures, you can do a poor man's aerochrome with a 100% analog process. Take one exposure with a cyan filter and another, much longer exposure with an IR filter.

My camera cannot do double exposures, nor do I have the right filters, but I'd love to see someone try this.

Yeah that’s an interesting idea, I wonder how it would turn out. I don’t have the right filters either at the moment but I’ll add it to the list of future test I’ve been meaning to do.

BAC1967 · Jun 23, 2025

With Aerochrome you use a yellow filter, I wonder what that would with Phoenix?

Abandoned Bus by Bryan Chernick, on Flickr

F4U · Jun 24, 2025

I was never into Ektachrome Infrared back in the day. It had one use: military. I twas made for aerial jungle photography to separate the enemy camouflage in the jungle from actual live growth. Wherever there was a red patch in a jungle photo, they knew where the guerillas were hiding. Surplus was marketed to the public, but has no aestheic or pictorial use, then or now. On the other hand, we still have near-infrared black and white film available.

MattKing · Jun 24, 2025

F4U said:
I was never into Ektachrome Infrared back in the day. It had one use: military. I twas made for aerial jungle photography to separate the enemy camouflage in the jungle from actual live growth. Wherever there was a red patch in a jungle photo, they knew where the guerillas were hiding. Surplus was marketed to the public, but has no aestheic or pictorial use, then or now. On the other hand, we still have near-infrared black and white film available.

FWIW, although there were military uses for EIR, its largest application was related to monitoring forests from the skies - both with respect to their health, and the mix of types of tree cover.
As for the aesthetic and pictorial use - there is some spectacularly compelling work out there.

MattKing · Jun 24, 2025

I hope he doesn't mind me linking to this, but my friend @PhotoBob is a fan of false colour Infrared film, and this image from his Photrio Gallery uploads is a good example of what can be done: https://www.photrio.com/forum/media/alouette-lake-stump.61791/

F4U · Jun 24, 2025

MattKing said:
FWIW, although there were military uses for EIR, its largest application was related to monitoring forests from the skies - both with respect to their health, and the mix of types of tree cover.
As for the aesthetic and pictorial use - there is some spectacularly compelling work out there.

I hadn't thought of that. Ektchrome Infrared was conceived to separate chlorophyll green from non-living green. Stands to reason that patches of live forest , the film could separate living from dying or dead underbrush. Thank you.

arturo_rs · Jun 24, 2025

I´ve been thinking about this:

To shoot 3 frames with Adox HR50. One with 720nm filter, another photo with a red filter and another with a green filter.
Later, with a color enlarger to make this:

So, the filtration por each photo has to be: Red for the infrared photo, green for the red filter photo and blue for the green filter photo.
It is complicated, density for each one, etc... but...possible?

arturo_rs · Jun 24, 2025

By the way, got the idea from this sites:

An Analog Aerochrome Film Replacement

In a few previous projects, I investigated ways to create images that look like the famous Kodak Aerochrome infrared film. As a film stock that is just not available anymore, we must look for ways …

teaandtechtime.com

Re-Creating The Unique Look Of Unobtainable Aerochrome Film

Ever heard of Aerochrome? It’s a unique type of color infrared film, originally created for the US military and designed for surveillance planes. Photos taken with Aerochrome film show trees …

hackaday.com

arturo_rs · Jun 24, 2025

Also, the Aerochrome datasheet.

arturo_rs · Jun 24, 2025

Another option will be using a yellow filter with the infrared, red and green filter.

Infrared + Yellow
Red + Yelloow
Green + Yellow

dcy · Jun 24, 2025

The problem I see is that, as @koraks pointed out, the IR and red filters will both produce cyan dye so can't be distinguished. I think the way to go is to allow Phoenix to deviate from Aerochrone:

Aerochrome:

Removes blue (via yellow filter).
Maps IR --> Red, Red --> Green, Green --> blue.

"Aero-Phoenix"?:

Remove red (via cyan and IR filters).
Map IR --> Red, Green --> Green, Blue --> Blue.

This would be a different look than aerochrome, but it would be interesting, and it would even retain the property of distinguishing live vegetation from dead stuff that is colored green.

dcy · Jun 24, 2025

I wish my camera could do double exposures. Without that, the only way I could try "aero-phoenix" would be to take two shots and merge them digitally.

For a digital process, I wouldn't technically need a cyan filter. I could remove the red channel in post, and then replace it with the red channel from the image that had the IR filter.

blee1996 · Jun 24, 2025

In the name of science, I ordered a Cyan filter (Kodak CC40C) for the potential experiment. I already have 655nm and 720nm IR filters, as well as a couple rolls of Phoenix.

False color IR with Harman Phoenix?

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