I wrote earlier about Cathedral Gorge, and posted some of my 3D photos. The gorge is a small park in Nevada along US Route 93, and is home to slot canyons and hoodoos.
I figure it’s about time to finish off that site with some multispectral photos. Unfortunately, I didn’t take many of them. I only took a more detailed photo of the one hoodoo in several spectra. It doesn’t look bad in the visible spectrum, not by a long shot:
Broken down into the red, blue, and green channels, there are no real surprises. Unlike some of my other photos, each channel of this photo is distinct. The blue channel seems to have the best detail for the hoodoo, but the sky is faded and the clouds are almost invisible. Conversely, the sky is best defined in the red channel, as normal, but the hoodoo is almost too bright to make out any layers in the stratigraphy. It makes sense; the tan colour of the rock hints at a lot of red light being reflected. There are no surprises with the visible channels… and a spoiler: there aren’t any outside the visible range either.
As a better mode of comparison, here the three colour channels are presented as a GIF file, because for some reason I do that now.
I didn’t take a full UV photo(no tripod to hold the camera still), but I did take a photo with my short band pass filter(allowing ultraviolet, violet, and a little blue light) into the camera.
Most times, the white balance settings don’t work with this filter(understandable, as it’s a scientific filter I jury rigged to function as a camera filter). This photo isn’t any exception- the purple colour is as best as the camera could do to compensate for the filter. The photo overall is fairly similar to the blue channel- the sky is extremely bright, and the hoodoo has good contrast.
Again, don’t complain about the white balance. Without it, this is what the photo looks like:
It’s very… purple. That means maybe ultraviolet, doesn’t it? With this photo, accessing the shorter wavelengths outside the visible spectrum means that you can see…
.. honestly, you can see nothing. The picture is completely indecipherable, and I wouldn’t even know what I was looking at without the other photos. I’ll give my camera a passing grade for making something legible out of this photo, even if it couldn’t fully correct the colour.
On the infrared end of the spectrum, my Zomei 760 nm filter provides a great contrast with the sky.
The small tree in the far left seems to be slightly more blue than the surrounding scrub brush. It might just be that the brush is more sparse, or that only a portion of it is alive. I really don’t know, and have no way of finding out anytime soon. Again, the shadows are clearly defined, but not the layers of the hoodoo.
Finally, with my Schott UG11 filter, I can take a photo in both the infrared AND ultraviolet wavelengths.
With the deep blue sky, it is fairly dramatic. The hoodoo looks similar to the infrared photo- extremely bright, almost overexposed. Thee’s not much else to say about this photo.
And that’s about it for Cathedral Gorge. If I go back that way, I’ll definitely plan to explore it some more… that said, I don’t have any plans to head to Nevada again for a while.
And with that, I just want to point out that I posted eight photos and a gif of the same mound of dirt from the same angle, and wrote all about it. Hooray!
The above photos were taken with a modified Canon Rebel T3i camera.