Reflected in Rose's TV.
Reflected in a brass panel on the front of the Renault that Jack and Rose find in the cargo hold.
Reflected in the glass door opened for Jack as he enters the dining room.
It is impossible for voices to echo in the middle of the North Atlantic unless there is a large, flat object like a ship nearby.
Rose's paintings include Picasso's "Les Demoiselles d'Avignon", one of the ballerinas series by Degas, and "Water Lilies" by Claude Monet, none of which were ever on the Titanic.
During the scene when Rose "flies" from the ship's bow, the sunlight is clearly falling almost exactly straight across the ship from left to right. On the evening of the 14th, the ship would be steaming somewhere between WSW and SW; the lighting in the movie would indicate that the sun is between SSE and SE, when it actually would have been between W and WNW.
The painting over the fireplace in the Titanic's first class smoking lounge in the film depicts New York Harbor, which was actually the painting on the Titanic's sister ship, "Olympic". The painter, Norman Wilkinson, had provided a scene of Plymouth Harbor for Titanic, but no pictures of this work survive.
There was no door between boiler room 6 and the cargo area (and no access to any but authorized crew). If there had been a door, it would have entered the third cargo area aft, not the one where the Renault was stored.
The main characters have lunch in the Palm Court/Verandah on A Deck. These were not used for dining, although passengers could order tea or a small snack.
Cal orders lamb with mint sauce for himself and Rose. Lamb was only available for dinner on the ship, while mutton was reserved for lunch. The lamb was prepared in the D-Deck galley and would not have been served in the Palm Court.
The real Titanic had a navigation light on the stern that is missing in the film.
Jack is shown having to rush to make sure he caught the Titanic before it sailed. Many other steerage passengers board along side him. In fact, all steerage passengers were aboard well before the ship sailed; first class passengers did not begin boarding until all the steerage passengers were aboard.
The Titanic's middle propeller was not used for manoeuvring in port, and hence would have been stationary when starting away from the dock.
The worship services held at 10:30 on Sunday April 14th, 1912, in the First Class Dining Room were open to all passengers of the ship.
In overhead shots of the forecastle deck, the skylight for the crew's galley can be seen located to starboard. This skylight was actually on the port side.
Jack is supposedly held prisoner in the Master-at-Arms' office, which is depicted as having a porthole. On the Titanic, this room was an interior room and hence would have no portholes.
Workers in the Titanic's engine room had to wear thick protective clothing to shield them from the heat generated by the engines.
Margaret Brown was never refered to as "Molly" until after her death.
When Captain Smith orders, "Take her to sea, Mr. Murdoch -- let's stretch her legs", they are standing to the right of the wheelhouse looking forward with the sun coming from their left. When Murdoch walks into the wheelhouse to carry out the order, the sun is behind him.
Jack takes Rose and Molly's arms to go into dinner. They start walking, but in the next shot they are still standing apart.
In the scene where Jack is teaching Rose to spit, there is no spit on his chin as he starts to turn around to face the ladies, but by the time he has completed his turn he has some on his chin.
The draft markings on the Titanic's bow when Jack looks at the dolphins later change size and position.
Jack claims to have gone ice fishing on Lake Wissota, which wasn't created until five years after the Titanic sank.
"Almighty Father Strong To Save" is sung during the worship service; the two verses used in the film were written by Robert Nelson Spencer in 1937.
The button on the left side of Jack's borrowed jacket is a "Kingsdrew" button, first made in 1922.
Jack claims to have visited the Santa Monica Pier, which did not begin construction until 1916.
The pipe frames supporting the third class berths have set-screw speed rail fittings, not developed until 1946.
A closeup of Captain Smith reveals that he is wearing contact lenses.
While Jack and Rose are walking on the promenade the day after he rescues her, a small hill with a building on it is visible over Jack's shoulder and above the ship.
In the same shot, the faces of Jack and Rose are lit from a different angle, though still from the left.
A strip of desert is visible between the dock and the Titanic when docked at Southampton.