Considering that the real Titanic ship sank in 1912, it would be tough to have actual footage from the event. To make due, James Cameron filmed all of his shots in a studio. These behind the scenes shots show the studio tank that was used to get the final moments of Jack’s… SPOILER… life. There were 350,000 gallons of water in this tank, and while it wasn’t ice cold water, the actors were cold when they were exposed to the air. There was a hot tub nearby which they would be able to use to warm up between shots, so don’t start feeling too bad for these poor souls. That means that the blue lips and pale skin was all makeup—illusion shattered.