- Edited
I don't know enough to say really, don't be deceived by my authoritative language style! I am writing up my doctoral thesis at the moment, so naturally everything else I write ends up in the same style.
if you rotate a linear polarisation filter against linearly polarised light at some angle it will go black as your filter blocks out more or less of the polarised light. The colour effect in your first video, I don't know what is going there. The second video is unavailable for me.
I'm buying some different polarisation films, so perhaps I will understand more what's going on in your first video if I can reproduce it.