Color Infared

EASmithV · Sep 13, 2009

I know there is EIR and Aerochrome, but surely there has, in the past, been other companies that do it? Has there ever been a Color IR c-41 film? Because that would have been amazing. Why are all the color infared films I've heard about chromes?

railwayman3 · Sep 14, 2009

I've always understood that the Kodak Color IR was designed for specialist military/aerial/scientific work, where the "false color" rendering enabled sources of infra-red and objects/plant diseases, etc., to be more easily identified. The packaging as 35mm for amateur and pictorial use was maybe something of a sideline?

I wonder if a C-41 IR film would have enable this object identification, etc., to show up more clearly....if not, there would not seem to have been an obvious use for it? But maybe there was such a film for specialist use and it was not packaged for general sale? Or perhaps the B&W IR negative covered what was needed?

AgX · Sep 14, 2009

EASmithV said:
Has there ever been a Color IR c-41 film? Because that would have been amazing. Why are all the color infared films I've heard about chromes?

Of all the false-colour IR films there was none designed for C-41. Though there have been negative films.

Photo Engineer · Sep 14, 2009

EIR cross processed gives amazing results. Sometimes the tone scale is reversed but the colors are normal and other times the tone scale is normal but the colors are reversed.

PE

benjiboy · Sep 14, 2009

Kodak Aero Ektachrome was used in forrestery to identify if trees were alive or dead, and for military aerial recon. to see through camoflage.

AgX · Sep 14, 2009

Ben,

It was rather intended at distinguishing between camouflage and real plants, not to see through camouflage.

Photo Engineer · Sep 14, 2009

Well, actually, modern IR films could see a hot truck through some camoflage or could see places in parking areas where hot trucks were parked. You are both right depending on situation.

PE

AgX · Sep 14, 2009

But you would need a lot of darkness and a lot of patience too...

(But there are electronic sensors which can do so under practical circumstances.)

TheFlyingCamera · Sep 14, 2009

I would think that the reason it was never made as a negative is that because it is "false color", there would be absolutely no way to calibrate the print color. You couldn't shoot a Macbeth color chart with it and then compare the print against the Macbeth.

Ektagraphic · Sep 14, 2009

Kodak still makes Aerochrome which is color infrared E-6 film. They only make it in large sizes, but there is a guy selling it rolled up into 120 on ebay and on his website.

EASmithV · Sep 14, 2009

benjiboy said:
Kodak Aero Ektachrome was used in forrestery to identify if trees were alive or dead, and for military aerial recon. to see through camoflage.

From what I've read, it still is.

Ektagraphic said:
Kodak still makes Aerochrome which is color infrared E-6 film. They only make it in large sizes, but there is a guy selling it rolled up into 120 on ebay and on his website.

Does he cut it to 4x5 sheets? Unfortunately, 120 is probably the one common format I don't shoot...

TheFlyingCamera said:
I would think that the reason it was never made as a negative is that because it is "false color", there would be absolutely no way to calibrate the print color. You couldn't shoot a Macbeth color chart with it and then compare the print against the Macbeth.

As long as the color was different enough to be distinctive and identifiable, I don't know why it would have to be perfectly calibrated. One would think that the extra latitude of negative film would have been of more importance.

nickandre · Sep 14, 2009

TheFlyingCamera said:
I would think that the reason it was never made as a negative is that because it is "false color", there would be absolutely no way to calibrate the print color. You couldn't shoot a Macbeth color chart with it and then compare the print against the Macbeth.

You'd have to set the base of the film to grey and get what you get. You could always push it around to see what you like best.

nickandre · Sep 14, 2009

EASmithV said:
Does he cut it to 4x5 sheets? Unfortunately, 120 is probably the one common format I don't shoot...

I believe the base is too thin to use with 4x5 equipment. Too bad really.

benjiboy · Sep 15, 2009

AgX said:
Ben,

It was rather intended at distinguishing between camouflage and real plants, not to see through camouflage.

Agreed, AgX, thanks, I didn't explain it very well, but that's what I meant .

Photo Engineer · Sep 15, 2009

I'll have to be more specific too.

Some IR films can "see through" camoflage. An encampment or hot equipment can actually be viewed through most camoflage. You have to use some pretty sophisticated camoflage to fool modern IR detectors. This includes heat dumping or your area becomes intolerably hot if the camoflage is built to limit heat emissions.

PE

Anon Ymous · Sep 15, 2009

PE, do you mean that there are/were films sensitive to 1000nm? IIRC, thermal cameras see at that wavelength and above

EASmithV · Sep 15, 2009

tiberiustibz said:
I believe the base is too thin to use with 4x5 equipment. Too bad really.

I contacted the guy who cuts this stuff to size, and he said,

"hello,

yes, cutting 4x5 sheets is a bit challenging, but i do offer it.

the film is not exactly designed for that. the material tends to bow a bit in the film holder, so you have to be careful with that, but it does work. i charge the same price for my material regardless of whether you buy 120 rolls, 4x5 or 5x7. is isnt cheap!

i cut a minimum of 12 sheets per order at a cost of $8.00 per sheet. so that would be $96.00 for 12 sheets.

dean bennici"

Sirius Glass · Sep 15, 2009

Anon Ymous said:
PE, do you mean that there are/were films sensitive to 1000nm? IIRC, thermal cameras see at that wavelength and above

There are infrared detectors that determine infrared beyond 0.9 microns [900 nm]. These can be in digital cameras, but I believe PE is referring to electro-optical equipment.

Steve

Photo Engineer · Sep 15, 2009

Anon Ymous said:
PE, do you mean that there are/were films sensitive to 1000nm? IIRC, thermal cameras see at that wavelength and above

There were films that see to that wavelength and beyond.

See attached wedge spectrograms! The long IR film data is actually truncated due to the equpment itself. The film sees beyond that a bit.

PE

Aurum · Sep 15, 2009

Kodak Buzz Lightyear film

Anon Ymous · Sep 15, 2009

Photo Engineer said:
There were films that see to that wavelength and beyond.

See attached wedge spectrograms! The long IR film data is actually truncated due to the equpment itself. The film sees beyond that a bit.

PE

Interesting! Have you got any idea about the expected life of such a film? How soon would it expire?

TIA

AgX · Sep 15, 2009

PE,

That there where at least plates sensitized up to 1100nm or so is no doubt about.

But about your statement on their practical use in imaging covered objects the way you described.

Photo Engineer · Sep 15, 2009

In previous posts here, the 1000 nm was doubted.

I doubt if I could convince you of viewing a covered object, but there are foil like camoflage blankets that supress the imaging of a hot vehicle (or cannon). You cannot see through this but can see the edges sometimes as they radiate some heat. And, they become quite hot underneath

A plain camoflage blanket would radiate heat. You can see through this latter type of camoflage with IR film. Even so, after the truck or other vehicle left, there would be a hot ground signature that could be used to identify even the vehicle type. This is especially true in many rural areas where you can even track the vehicle to and from several stopping points by the hot spots they leave on the ground.

It is often necessary to cover your stopping points with camoflage after you leave just to cover stop points where you may have created a supply dump.

Basically, all I say can and has been done.

PE

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