Rose: You have a gift, Jack. You do. You see people.
Jack: I see YOU.
Jack: You wouldn't have jumped.
When the men are checking the store room for Rose and Jack, the men are using huge battery powered bright white flash lights that look like they're from Jurassic Park, which were not around in 1912. Back then they would have produced yellow light.
The grand staircase in the movie was actually larger than the real one. Many things were either made bigger or smaller to make Titanic seem more 'Titanic.'