Robert Lamb, Writer and Storyboard Artist at Filmation, described the backgrounds --
"Filmation had a black line style to their backgrounds that facilitated production. A black pencil cleanup of the blue pencil layout would be xeroxed onto a cel that would lay over the painted bg. This eliminated the need for the painters to noodle a lot of detail into the paintings. Annie and other bg artists didn't like the ink line but production costs won out."
And the black line style does provide lot of great details. Especially when looking at the main locations Castle Grayskull and Snake Mountain; you see many creaks and cracks that give them character.
I will be showcasing screencaptures of Filmation Backgrounds, from He-Man, using the US release (region1) of DVDs by BCI Entertainment. And also UK release (region2) by Entertainment Rights.
Hopefully you will enjoy the art as much as I do, when focusing on the backdrops, instead of the characters in the foreground.