To play the powerful android known as The Vision, actor Paul Bettany had to go through a two-hour make-up process. Avengers: Age of Ultron make-up artists Jeremy Woodhead and Nik Williams chatted with Make-Up Artist Magazine about the process and provided some terrific behind-the-scenes images of The Vision's make-up and costume.

Their first challenge was coming up the right skin-color for the synthetic humanoid. Red was chosen, but then they had to decided which shade of red? A bright scarlet was quicly eliminated as it "would look slightly absurd," so they went with a color that appeared to change depending on the lighting. "In some light, it looked pink and in others, red; it was like a red cabbage or beetroot color, a purple-pinky red," Williams explained. "It was a light-dependent thing, which necessitated a mix of colors and layers, so depending on the light, it would either pick up the red or pink."

The back of The Vision's head has patterns/lines that they felt required a precision-look because he was "born from a computer." They sculpted the "make-up in 3-D over a cyber-scan of Paul’s head and printed out in clear plastic" rather than making a cast of Paul's head and sculpting the make-up from clay or plasticine.

Williams added, "We originally tested facial prosthetics as well, but Paul has delicate features, so any prosthetics on top would take away from them, so we just ended up with a prosthetic forehead, back-of-head and neck, leaving the face free, which I painted to match the prosthetic."

Check out the images in the album below.

The epic follow-up to the biggest Super Hero movie of all time. When Tony Stark tries to jumpstart a dormant peacekeeping program, things go awry and Earth’s Mightiest Heroes, including Iron Man, Captain America, Thor, The Incredible Hulk, Black Widow and Hawkeye, are put to the ultimate test as the fate of the planet hangs in the balance. As the villainous Ultron emerges, it is up to the Avengers to stop him from enacting his terrible plans, and soon uneasy alliances and unexpected action pave the way for an epic and unique global adventure.

Marvel's Avengers: Age of Ultron will be available on Digital HD September 8, 2015 and on Blu-Ray October 2, 2015.