Yes, I did the thing from the Posy video. TLDR; he uses a polarizing filter and some clear plastic to selectively color only polarized light.
By putting some cheap plastic in front of the filter, the polarization of some wavelengths changes. The polarizing filter then filters away those wavelengths. And since much of the sky is polarized, it takes on funky colors :3
As you can see, the trees or the clouds are unaffected by the colors. The effect works on the sky, as well as any of its reflections.
If the Ground is reflective enough, even that works!
Some experiments
I did some more experiments with this concept. I was wondering when colors would appear so I stuck a polarizer on my phone flash and put the CD case on top of it. In these pictures you can see a few things:
- the light viewed through the camera indeed looks colored
- when the light is scattered it looks white again
- when the light reflects off something mostly shiny it stays colored
The color also strongly depends on the viewing angle, as seen in this video.
All taken with a Nikon D5600, the stock lens, an amazon basics CPL Filter and Hama Clear CD cases.