After filming the underwater shots, Cameron began writing the screenplay.  He wanted to honor the people who died during the sinking, so he spent six months researching all of the Titanic ' s crew and passengers.  "I read everything I could. I created an extremely detailed timeline of the ship's few days and a very detailed timeline of the last night of its life," he said.  "And I worked within that to write the script, and I got some historical experts to analyze what I'd written and comment on it, and I adjusted it."  He paid meticulous attention to detail, even including a scene depicting the Californian ' s role in Titanic 's demise, though this was later cut (see below) . From the beginning of the shoot, they had "a very clear picture" of what happened on the ship that night. "I had a library that filled one whole wall of my writing office with Titanic stuff, because I wanted it to be right, especially if we were going to dive to the ship," he said. "That set the bar higher in a way – it elevated the movie in a sense. We wanted this to be a definitive visualization of this moment in history as if you'd gone back in a time machine and shot it."