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Tonight, it’s Missoula, Montana. Only a place like this could a person like David Lynch be from.

We had a pleasant drive from Bozeman to Glacier National Park. I did a little bit of noodling with the infrared filter on the digital camera. Here’s something a lot of people don’t know. If you put an infrared film filter, like an 87 or 87C, on any digital camera with a CCD capture sensor, you can overpower the infrared suppression filter on the chip itself. CCD’s are inherently more sensitive to infrared than visible light. That’s why they have a suppression filter. CMOS capture sensors, however, are not. To my knowledge, only Canon uses CMOS sensors (at least among the small format manufacturers). Of course, since you have to overpower the suppression filter, I have found that I need to open up about 10 stops from a normal exposure with my Olympus E-300.

So, I’m going to nerd out a little bit here and give a brief technical description of what color is. Color is our brains’ interpretation of certain wavelengths of the electromagnetic spectrum. The band of the EM spectrum human eyes are sensitive to is generally around 400 nanometer wavelengths to 700 nanometers. What we perceive as blue is down around 450 nanometers, green is around 550 nanometers, and red is up around 650-700 nanometers. Wavelengths shorter than 400 nanometers fall into the ultraviolet range, and then x-rays, gamma rays, and cosmic rays. From 700 to 900 nanometers is the infrared range. Above that, you have microwaves and eventually radio waves. But all we can really see is 400-700 nanometers. Thermal imaging, UV imaging, infrared imaging… all of that is false color. What they’re doing is taking wavelengths outside the range of visible light, and reassigning it a value inside the range of visible light so that we can see it.

So, now that I’ve explained that, I can show what I’ve done. This first image is of a scene on US-89 in Montana showing visible light:

Next is the same scene with an infrared transmission filter over the lens, which filters out all visible light:

Okay, pretty cool, but we’ve probably all seen black-and-white infrared by now. So, something I’ve been thinking about for a little while is how to get the contrast qualities of black-and-white infrared in a color image. The first experiment involved simply placing the infrared image on a new layer above the regular color image in Photoshop and setting the blend mode to “Luminosity.” I left the opacity at 100% as a starting point. I may decide to season to taste:

And finally, because I felt like it, I decided to create some false color. The challenge was essentially how to compress 4 channels into 3. In an ordinary digital image in RGB color mode, you have three channels–red, green, and blue. I wanted to add a fourth channel–infrared. At first I thought I’d just add the infrared exposure as an alpha channel in Photoshop and play with the channel mixer. Unfortunately, the channel mixer will not use alpha channels as source channels. So, I ended up playing with the Apply Image function and reassigned some values to the channels. The blue channel is now 75% of the original blue channel and 25% of the green. The green channel is now 50% of the original green channel and 50% of the red. And the red channel is now 25% of the original red channel and 75% of the infrared image. The blend mode was always set to normal, and an alpha channel was used as a temporary holding space while I juggled the values around. I’ll see if I can find a less clunky way to do this in the future. In the meantime, here’s the false color:

Anyway, after that little experiment, we went on to Glacier National Park, where I shot mostly video. I don’t have the conversion software on my laptop, so video will have to wait until I get home. Glacier National Park is pretty spectacular though. I think what I enjoyed the most was the large number of small waterfalls dumping snowmelt almost directly onto the road. It was like something they would fake at Disneyland.

After Glacier, it was on to Missoula, where we are now. This is a weird place. I’m not sure how to describe it. I would have to say that of all of David Lynch’s movies, Blue Velvet is the one that seems most Missoula-like.

Anyway, no KML file tonight because it’s after midnight and I’m tired.