How Some Cool Silent Film Effects Were Made Before CGI
Harold Lloyd hanging off a clock in Safety Last! (1923)
How it was done: When Safety Last was made, inserting a fake background with the use of rear projection or a green screen is not attainable, so they utilized a trick of perspective. The set was built with the exact height for Lloyd's climb, but on the roof of a building just across the street. As Lloyd climbed higher, the set was also moved to taller buildings.
Charlie Chaplin roller-skating in a department store in Modern Times (1936)
How it was done: Charlie Chaplin roller-skating in a department store in Modern Times (1936)
This is a good example of the classic movie-making technique using glass matte painting. Part of the background was painted on a piece of glass, then placed in front of the camera.
Colleen Moore's eye trick in Ella Cinders (1926)
How it was done: The two halves of her face were separately filmed utilizing a matte shot. A piece of glass with half the frame painted black was primarily positioned in front of the camera, exposing only one side of the film. Then it was wound back, the glass was switched over for one with black on the other side. The secret was to avoid having either the camera or Moore's face alter its position while shooting, or else the effect would be ruined.
Mary Pickford kisses herself on the cheek in Little Lord Fauntleroy (1921)
How it was done: Viewing two Mary Pickfords in the same shot wasn't that new for audiences, it was also attained in Stella Maris three years early. Decades ago, Georges Méliès had determined how to appear multiple times in one shot using mattes and double exposure. However, in shooting a double exposure, usually the actor can't move from one part of the frame then to another without ruining the effect. The famous cinematographer, Charles Rosher, achieved this effect by having Pickford move behind her own face then having a very intricate silhouette of Pickford painted on glass, and usage of a metal frame to prevent the camera from moving. The three-second shot took about 15 hours of work to get right.
Douglas Fairbanks slides down a sail in The Black Pirate (1926)
How it was done: The technique for achieving this much copied shot was determined by Fairbanks's brother Robert, who is an engineer. Both the camera and the sail were positioned at an angle. Fairbanks's knife was attached to a hidden pulley and counterweight. Airplane propellers were utilized to make the sails billow.
Buster Keaton rides over a broken bridge in Sherlock Jr. (1924)
How it was done: Another matte shot. The bottom of the frame was blacked out, then lined up with the top of the bridge, and the shot was taken with Keaton riding while the bridge was still intact. The footage of the trucks was shot separately with a sector of the bridge removed. Right timing was very crucial. The scene at the end isn't a camera trick, Keaton really did that.
Jesus heals some lepers in Ben-Hur (1925)
How it was done: Karl Struss, another famed cinematographer, discovered a technique using a colour filter to attain this effect. After filter adjustment, the women's leper makeup was no longer visible on film. Struss also used this technique, but in reverse, for the transformation scene in the famous movie of Dr. Jekyll and Mr. Hyde (1931).