As promised, here are a couple of stages of sketching on the 16" X 20" canvas. I start out with a regular pencil before going over the important lines with a black colored pencil. The graphite tends to wash off the canvas when I apply the acrylic tone and what remains is so faint, I can't see what I drew, so the colored pencil keeps it visible. It all gets covered up with oils anyway.
In the image above, I was free handing everything and the only reference picture other than the movie still was a photo my brother took of his Kermit photo puppet (yeah, he's got one). It gave me a guide on which to base my lighting and color for the frog. However, since I just started drawing, I didn't center my image very well. I assumed that if I made it off center and at an angle, it would look cool and dramatic. Not so much.
Further research (read: Google) helped tighten up Miss Piggy's head but I still had the composition issue. Since I did not want to redraw everything, I had to think of something that would help balance the picture. Something outside the window? Sure! The Death Star? No, this image is from The Empire Strikes Back. Ooh! How about a Star Destroyer? Yeah, that'll work! Except I ran into a friend at work (Hi, Christina!) who joked about Pigs in Space, triggering the idea of the USS Swine Trek. Genius!