The Strange Realm of Infra-Red: 3

Kennedy assassination site in infra-red

(Charles Platt is a guest blogger)

While driving through Dallas, I stopped to visit the museum in the old Texas Book Depository building from which Lee Harvey Oswald took a shot (or two, or three) at John F. Kennedy. Two X marks have been etched into the asphalt, marking the locations where the president was hit. I was fascinated to see tourists running out into the road to have their pictures taken while standing on an X.

The Book Depository looks especially good to me in infra-red

The ruthlessly modern, official Kennedy memorial, by architect Philip Johnson, is located just a couple of blocks away, but relatively few people seem to go there, perhaps because they are more excited by the guilty thrill of an assassination site which shamelessly admits what it is.

Another possibility is that Johnson’s memorial is shunned because it looks like a giant urinal. (Just my opinion of course. YMMV.)



  1. One of the traditional uses for monochrome IR film was for shooting architecture, specifically because it yields this sort of hyper-real feeling of bright buildings against dark skies.

    Fun shots, BTW. As folks have pointed out, it’s possible to trick many video and/or digital cameras into shooting IR by blocking the visible light, but a camera designed for the purpose (make the IR filter explicitly removable) is a fine idea.

  2. People are strange. You know, I bet if it was allowed, people would line up to have their pictures taken in front of the ovens at Auschwitz. I just don’t get it.

  3. I’d be interested to see this contrasted with conventional black and white prints. To me, this looks like a standard B&W shot in which the trees’ leaves are a lighter shade of yellow.

  4. “from which Lee Harvey Oswald took a shot (or two, or three) at John F. Kennedy”

    allegedly took shots…

  5. Yes I should have taken regular B&W shots to compare with infra-red. If I had done so, I think you would have found that the sky would not be so dark, and the trees and sidewalk would not be so white, to a very noticeable extent.

    Ansel Adams, of course, used deep red filters when photographing many of his landscapes on monochrome film, thus achieving high contrast between clouds and sky.

    I should add that some Photoshop work was required in my pictures. The camera that I used (Fuji IR-1) transposes infra-red frequencies by reassigning them to the usual R, G, and B channels, but does this unequally, giving the picture a red cast which I assume was an aesthetic judgment call by the designers (“infra red” should look “red,” right?). If you simply convert this RGB picture to monochrome, you lose a lot of contrast. In many pictures, image data simply disappears.

    So, the way I do it is to go into each channel in Photoshop and set the white and black points manually, thus spreading the data in each channel over the full dynamic range. (I often find that infra-red shots use only about half of the available range in the blue channel.)

    Then I convert to monochrome by opening the Hue, Saturation, Lightness window and moving Saturation down to zero. I do it this way because when Photoshop is allowed to convert RGB to monochrome automatically, it weights the green channel more highly than the others. This is useful in converting everyday full-color to monochrome because a) greens are in the center of the visible spectrum and b) the G channel often has more contrast in it than the R or B channels. But for infra-red, it’s not appropriate, since nonvisible light frequencies are being assigned arbitrarily to visible frequencies, and therefore “green” is not green at all.

    (Back when I was studying at the London College of Printing, an incredible number of years ago, I was told that printing companies always use a green filter on gallery cameras when photographing color art that is to be reproduced in monochrome. So, there’s nothing new in weighting green more heavily when doing a color conversion.)
    My Fuji camera can be allowed to convert an infra-red shot to monochrome in its own firmware, but I found the results from that process to be worst of all, in terms of losing image data.

    Finally, after converting to monochrome using the system described above, I find I have to spread the lighter tones (by adjusting Curves) to achieve reasonable contrast in vegetation. Leaves that are in shadow look almost as pale as leaves that are in sunlight, tending to produce a generally bleached look, unless contrast is added.

    And, I tend to compress the dark tones to get a “noir” look which I think is appropriate for infra-red shots.

    When taking the pictures, I use an infra-red filter that cuts almost all visible frequencies. For a more hybrid, gentler effect, you can use a filter that admits some visible light.

    Just in case anyone is interested…

  6. I’d love to see a photo taken with RGB + Infrared, affected so that the infrared is overlayed on the RGB via white level = saturation. Trees would show up glowing green, sky would be deep grey… might be a really interesting look!

  7. @5: Hope I’m not out of line linking to my own site, but I think this close-up of a plant demonstrates the effect better. The blazing white plant is actually dark green and the black background is actually a bright blue sky. There is a false colour cast which I left in there. I’ve only adjusted the levels a bit, as with that particular camera, the images come out a bit underexposed. Unfortunately, I didn’t shoot a normal colour version of it for comparison, either.

    @8: Technically, it’s near-IR, not thermal/far-IR, which is down the spectrum a bit more.

  8. IR has become a gimmick.

    It can be art..but rarely.

    CP did a very good job and provided a great explanation.

    Proving that even cliches may still have some room to maneuver.

    Nice work CP.

  9. @10: I decided to whip this page up. It shows the original photos and a couple of mixed photos. The photos aren’t that great (it’s the only shot with IR and normal I have, taken long ago), but I hope it gives people an idea of what it looks like when you mix them. Of course, the look can change dramatically depending on the scene, and there’s nothing stopping you dumping the IR photo into the blue channel etc., either — it’s quite fun to play with different combinations.

  10. #3: I went to Auschwitz/Birkenau in the 80s and I don’t recall anything stopping anyone from taking photos in front of whatever they wanted. Now.. Well, just google ‘ auschwitz tourist’ (actually it’s surprising how few contemporary photos there are with people in them at all, something of a relief in some weird way).

  11. Last time I was at the memorial (about 10 years ago, when it served as a neutral, public space to meet irl the mother of a young girl who had duped me into believing she was much older online), there was an early-1960s Lincoln convertible that had been done up with flags, extra chrome, step bumpers, etc. to turn it into a sort-of-but-not-very-close replica of the limo in which Kennedy was shot. They were offering to retrace the motorcade route for something like 10 bucks a rider.

    Somehow I found it offensive. I can’t really explain why. Anybody know if it, or something like it, is still running?

  12. I was experimenting with my old digital camera’s infrared capabilities a few weeks ago. At that point, Google wasn’t telling me that there was a filter inside the camera, but, I can see the infrared light on a TV remote with just about all the digital cameras I own, no modification.

    So my only problem was building a filter. I tried a few different types of ink and some other stuff that was lying around but couldn’t really block just visible light. Anyone know how I might build such a thing myself?

  13. “giving the picture a red cast which I assume was an aesthetic judgment call by the designers (“infra red” should look “red,” right?)”

    There’s no such judgement. They’ve simply given you a camera that doesn’t have a hot mirror (IR-cut filter) from the factory.

    You get a lot of infrared in the red channel because the red filters in the Bayer array pass more IR. This shifts the color balance of the whole image towards the red.

    You can set a custom white balance in-camera which will get you closer to neutral, at least if you’re shooting JPEG. If you’re shooting RAW, you have a whole different set of problems, which is why I wrote up the rant I posted earlier.

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