James Gurney in his book Color and Light talked about rare cases when you would see shadow beams where clouds or contrails would cast shadows down to the ground. He explained that the sky behind the shadow beams had to be hazy and lighter so they would show up. He cautioned against using them too much since they “attract a lot of attention.”
I don’t know if I’ve ever seen a painting that used reverse shadow beams.
I wonder what Mr. Gurney would say about them?