Hey, i just wanted to know your process for doing this piece/what program you used, because I had an idea for a similar composition, except it was Doctor Who related and having to do with blinking and angels.
Well first you're drawing the eyes, then I animate the falling "comets" (each on a different layer). Then I choose a specific image. It's with that image that the light on castiel's face will be the strongest. The light being on a different layer than the rest. Then you have to change the opacity of the light layer to show a continuity.
Then for the closing eyes; it's on two differents layers: one with the eyes half closed, one with the two eyes closed.