Posted: Aug 11, 2017 1:52 pm
by GrahamH
It would help if you watched the video.
https://youtu.be/VIg5HkyauoY?t=19s for rainbows without blue. It's only 19s in FFS.

For skies I think it was actually that they had no word for blue, so green and blue were the same thing linguistically. Water was depicted with green pigments, but water can look green so that's unsurprising.