The Strange Realm of Infra-Red: 4

Desert highway in infra-red

(Charles Platt is a guest blogger)

Just one more sample. While agreeing that infra-red photography can be a gimmick (similar to false color, oversaturation, and many Photoshop effects) I like the way it seems to reveal another world that is inherent in our own.

The desert topography, the black sky of an infra-red photograph, and the clarity of desert air combine to create a landscape that looks like a tabletop model. This picture was taken from an overpass just west of Phoenix on Interstate 10.


  1. I don’t think IR is a gimmick anymore than UV, or X-rays, or even normal RGB photography. Like the poster says, they allow you to see something that you otherwise can’t. Photoshop filters are a bit different. And either way, neither is inherently any gimmickier than anything else, anyway. Sure, simply shooting in IR isn’t necessarily going to be anything special if you’ve already seen it before, but just like normal color photography, how much artistic flair is put into it is entirely up to the talent of the individual who created it, not the medium or process.

  2. It’s all good, but it’s in b/w. How about IR photos in full colour? Well, 3 colours anyway. Snap two identical photos, one in IR, another a normal colour photo. Then apply the IR photo as a luminosity layer on top of the regular photo. So we get the IR effect, but on a normal colour photo. I’ll do it myself, but I don’t have access to a camera that can take IR photos.

  3. SOUPISGOODFOOD has it exactly right. Infrared is nothing at all like a pixel transform in terms of how it is created, or what meaning it carries.

    Pixel transforms show us adjustments of our usual color range. We might see more of the shadow or highlight detail, or a negative, or a nonlinear transform like solarization; but in the end it is the same set of brightnesses and colors that are sensed and transformed and displayed to give us the image.

    With an infrared (or UV) photograph, we are literally getting a chance to see how the world around us reflects a part of the spectrum we can’t normally see; extending our perceptions and our knowledge. This is *not* information we would have had anyway, adjusted to look different, as a pixel transform would do; this is new information entirely.

    You can only call this a “gimmick” if you don’t actually understand what it is you are looking at. These images represent actual reality — literally how the things around us reflect the colors over the rainbow. The red end of the rainbow for infrared, and the purple end for ultraviolet.

    The Chandra x-ray telescope is another example of how we can see in a new way, in areas of the spectrum where our eyes simply do not function. No gimmicks: Just real science, enhancing our ability to see what is actually there.

  4. ‘Infra-red’ is a vague term. There are about three bands in common use…

    ‘Near IR” is probably anything a bit longer than visible. Usually the visible range is quoted as 380-780nm, but unless you are looking at a LED in a darkened room, we are pretty much blind to most stuff beneath 700nm. These pictures probably have a peak sensitivity at about 900-1000nm. The infra-red films (almost all discontinued, now) peaked in this range, too. Cholorophyll absorbs red, but does not absorb infra-red, so all the foliage ends up with this frosty white appearance. Most lenses that work with visible light ought to work with this band with a bit of refocussing.

    The next band is about 1500-2500 nm region. Hot objects such as car engines emit IR in this band but, but warm objects such as animals merely reflect. Some open weave materials such as are used in yashmaks become semi transparent, which lead to brisk but unexplained sales of night sights to the Middle East for a while in the nineties – a story referred to earlier). Dichroic materials for the visible do not work at the longer wavelengths, you will probably need special optics.

    Water has an absorbtion peak so it is like looking through fog. The next band you can see anything is about 4000-7000 nm. In this band, warm-blooded animals appear to glow. The inside of your camera will glow too, unless it is cooled.

    You can go to even longer wavelengths. But if you are looking at an infra-red image, is is probably one of these three bands.

    The Kodak Aerochrome stocks were a three-colour film, with cyan, magenta and yellow dyes corresponding to IR, red, and green. Aerochrome pictures rarely looked like full three-colour prints because the IR emulsion was much slower than the others, and had a smaller density range. Prints often had vivid blues and pinks (and sometimes yellows, depending on the print, but greens (red, but no IR or green exposure) are almost impossible to achieve.

    The poster who thought that this looked like some digital image filter is not wholly wrong. I was asked to do a digital simulation of Aerochrome stock – it turns out you can do a pretty good fake from ordinary RGB data if you make the greens nearly white, and darken the skies. This isn’t real IR – a green dye might absorb IR and appear quite different to foliage of the same shade – but most shots look roughly right, and they all look pretty weird anyhow.

    UV might be fun to look at. My father had his eye lenses replaced with plastic ones, and for a while he saw twilight skies as being very deep blues (our eye lenses get yellow as we get older, so he probably had his blue restored, but he might have been seeing a bit into the UV too).

    (SFX: end of lesson bell)

  5. I’ve just come off of 48 hours of sleepless gamejam action, and personally have really enjoyed this IR series, it’s kind of gelled really nicely with where my sleep deprived head is at. :) Thanks……

  6. SoupisGoodFood…Do you happen to be a Dead Kennedys fan? I’m assuming you are…Wow…that song (which is your name) could never be more true in today’s economic climate. Jello Biafra was truly ahead of his time.

    Sorry to be off topic…the IR stuff is absolutely spectacular!

  7. A few years ago I was driving what was, I think, that stretch of highway shortly after the sun had gone down and the half-light was working with the long, straight road to create some really strange visual effects. Basically, looking at the horizon, my sense of what was sky and what was an object got totally reversed, and I thought I was looking at a big dark cloud where the sky was and the sky where the mountain was. I had to very consciously scan the rest of the landscape to re-trick my brain back into seeing things the way they were.

  8. @dainel (#14)

    I’ll do your full-color IR one better. How about a IR Luminosity channel full-color HDR image?

    I just got my Hoya R72 filter in the mail yesterday and did my first experiment with it today. Sorry it is such a simple scene; just using the view outside my first door.

    Took a series of regular exposures and combined them into an HDRI. Then put the IR filter on the camera and did another series of bracketed exposures. Extracted the red channel from the IR shots and combined them into another HDRI.

    Then replaced the luminosity channel in the regular HDRI with the IR channel. Not the easiest thing to do with only open source tools. Then also tone mapped each of the images. The above link is to a mosaic comparing the four different versions of the same scene. Notes on the mosaic link to each of the images.

    Check back with my flickr stream for further experiments.

  9. Following up on Dainel’s request for full color and Richard’s excellent explanation of the different IR bands, you might want to check out FLIR infra-red cameras. These respond down in the 3000 to 7000 nM range, converting the surface temperature to a color.

    They have a nice gallery of images here…

    Very expensive (several thousands of dollars. Even an IR lens is around $3500, typically made out of germanium.)

    I’ve used them at work occasionally, looking for equipment hot spots. Want to borrow one some weekend. This is the kind of camera that will show you where the heat is escaping from your house and stuff. Neat stuff.

    Dargaud, very nice work!

  10. Charles,

    My wife and I drove from Washington to Texas. We stopped in Flagstaff and Tucson. Went from 8000 to near sea level.

    Saw the Grand Canyon.

    Have to say, it is an amazing republic.

    Thanks for the posts.

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