To prepare for their roles, Robert Redford and Dustin Hoffman hung out in the Washington Post newsroom for several weeks, observing reporters and attending staff meetings. Once, when Redford was standing in a hallway, a group of high school students came through on a tour of the newspaper offices. The students immediately started taking pictures of Redford with their pocket cameras. At that point, Bob Woodward walked by. Redford told the students, "Wait a minute! Here's the real Bob Woodward, the guy I'm playing in the movie! Don't you want to take a picture of him?" The students said no, and walked on. Hoffman also recalled that he had been asked by the Post's science reporter to fetch a new typewriter ribbon. Due to Hoffman's long hair and casual dress, the science reporter had mistaken him for a copy boy.
The two lead actors memorized each other's lines so that they could both interrupt each other in character. This unsettled a lot of the actors they were playing opposite, leading to a greater sense of verisimilitude.
On Tuesday, May 31, 2005, in advance of a revelatory July 2005 "Vanity Fair" article written by his attorney and spokesman, 91-year-old W. Mark Felt acknowledged publicly for the first time that he was in fact the informant "Deep Throat," a fact corroborated by Bob Woodward and the Washington Post. At the time of the Watergate break-in, Mr. Felt was the Deputy Director, the second-in-command, of the FBI.
One scene involving Robert Redford on the phone is done in a continuous six-minute single take with the camera tracking in slowly. Towards the end Redford makes a mistake - he calls the phone caller by the wrong name - but as he stays in character it simply appears genuine and this was the take used in the final cut.
Hal Holbrook was the first and only choice to play the informant Deep Throat. During the casting process, Bob Woodward, while looking at various actors photo head shots and resumes, but not revealing Deep Throat's true identity, told and insisted to director Alan J. Pakula that Holbrook was the best choice to play Deep Throat. (Holbrook, in fact, bears a strong resemblance to W. Mark Felt).
The film was originally rated R for language. (this was most likely due to occasional usage of the F-word.) It was subsequently re-rated PG (most likely due to the historical significance of the material.)
The furious volley of typewriter keys striking paper in the opening scenes was created by layering the sounds of gunshots and whip-lashes over the actual sounds of a typewriter, accentuating the film's theme of words as weapons. This is also why the closing scene has a teletypewriter printing headlines with the sound of cannon fire from a 21-gun salute in the background.
When Kenneth Dahlberg tells Bob Woodward on the phone, "I've just been through a terrible ordeal! My neighbor's wife has been kidnapped!" he is not lying. On 27 July 1972, a few days before Woodward called Dahlberg, Virginia Piper - wife of a prominent Minnesota businessman and a close friend of the Dahlberg family - was kidnapped from her home in Minneapolis. She was released two days later in Duluth, after her husband paid a $1 million ransom.
Screenwriter William Goldman was called to an impromptu meeting with Redford (the film's producer) along with Bob Woodward and Carl Bernstein. At that time, Goldman's draft of the screenplay had been accepted and they were waiting on hearing from Woodward and Bernstein. At the meeting, they presented Goldman with a new screenplay - written by Bernstein, and then girlfriend Nora Ephron. Goldman refused to read the screenplay (for legal reasons) and walked out of the meeting. Only one scene from that screenplay ends up in the final version of the film: a scene where Bernstein outsmarts a secretary to get in to see someone. This scene was pure fiction - it did not happen in real life. (Woodward was allegedly unhappy with Bernstein's script as well, because it depicted Woodward as a naive novice reporter and worshipper of Bernstein's superior talent. Woodward later called Goldman to apologize for the incident, telling him, "I don't know what the six worst things I've ever done in my life are, but letting that happen, letting them write that, is one of them.")
Robert Redford was in contact with Bob Woodward and Carl Bernstein before their book had been written, and encouraged them to write more about how they conducted their investigation and less about the events they were reporting. (Vanity Fair article, 04/2011.)
Director of Photography Gordon Willis shot the scene where Bob Woodward talks on the phone to Ken Dahlberg in one take. He used a split diopter, which allows both the foreground and background to be in focus at the same time. That take is one long zoom shot.
William Goldman had to tone down the dialog from editor Harry Rosenfeld, played in the film by Jack Warden. Rosenfeld in real life was so hilariously funny that Goldman didn't think that people would believe someone could be so spontaneously witty.
Washington Post boss Katharine Graham, who was initially very apprehensive about the film using the paper's name, loved the film and later wrote a letter of praise and approval to star and co-producer Robert Redford.
During TV news coverage of the true identity of "Deep Throat"/W. Mark Felt that aired in 2005, Robert Redford stated that they tried to film in the actual Washington Post newsroom, but it proved impossible because many Post employees were too aware of the camera, and some even tried to "act". Redford stated some employees would disappear into restrooms and apply makeup. The production team recreated the facility at a Burbank studio in Los Angeles for a reported $450,000. The Post did, however, cooperate with the production's quest for authenticity by shipping several crates of actual newsroom refuse that included: unopened mail, government directories, Washington telephone directories, wire service copy, calendars, and even stickers from Benjamin C. Bradlee's secretary's desk.
The interior Washington Post newsroom set was built on a stage at Warner Brothers Studio, in Burbank, California. The film's production designer George Jenkins was a former New York Broadway scenic designer. Designing the newsroom based upon the actual newspaper's newsroom, George's plan layout utilizes false perspective in the rear set area to increase the depth and scale-size for camera. As the newsroom desks recede, the construction coordinator's prop makers cut each prop desk down in size to fill in, and match the reduced scale for each line of desks. Shelving was also reduced in size. When filming the set's front action area, the extra actors filling in the background set's scale, were selected related to their height fulfilling the perspective scale set dressing relationship. Viewing the film, the false perspective of the studio set accomplishes the size and scale of the actual Washington Post Newsroom.
The phone number that Bob Woodward dials and reaches a man who speaks no English is 305-374-1299, the usual 555- prefix was not used. It is a real number, used by Net Capital Mortgage in Miami, Florida.
According to "Adventures in the Screen Trade", Alan J. Pakula drove William Goldman barmy asking for rewrites for scenes with the constant rejoinder "Don't deny me any riches!" Goldman goes on to say that if he could have his career all over again, he wouldn't go near this film.