This was, obviously, inspired by the climax of Return of the Jedi. I've always loved that moment when Darth Vader stands by watching The Emperor electrocute Luke Skywalker, who is pleading for his father to help him. That moment is really powerful because we can't see behind Vader's mask; we don't know if he's unmoved or tormented until he makes his move. The background is blue, reflecting the color of Palpatine's Force lightning, and I gave a red tint to the eyes to 1) introduce a new color to the composition and 2) try to suggest the swelling emotion within the Dark Lord of the Sith. I figured since Vader's original helmet design featured a reddish tint to the eyes, I could fudge a little.
"The Dark Side"
This one was suggested by the comic book mini-series Dark Empire, in which Palpatine returns to live within a clone body and tempts Luke Skywalker to the Dark Side. Luke believes he can get close enough to Palpatine to destroy him this way, but of course risks becoming that which he pretends to be. Luke was taken from Dave Dorman's painted cover for the first issue; I can't recall now where I got the image of Palpatine, but it's very likely also from a work of Dorman's. You can see where I tentatively placed the helmet of Darth Vader; I was never entirely sure he belonged in the sketch so I never returned to it. I thought about placing instead a Star Destroyer, and a few other things, but none of them ever felt right.