Maschinenmensch performer Brigitte Helm
The Maschinenmensch (literally 'machine-human' in German) is a fictional robot featured in Thea von Harbou's novel Metropolis and Fritz Lang's film adaption of the novel. In the movie, she is played by German actress Brigitte Helm both as a robot and in human guise. She was created by the scientist Rotwang in dedication to his deceased lover, Hel, though in the novel they have no correlation. Maschinenmensch was one of the first fictional robots ever depicted in cinema, and as a result popularized the concept worldwide.Film
The film version is different due to limitations of the practical special effects available at the time. The Maschinenmensch is a metallic automaton shaped like a woman. In the film version Rotwang proudly proclaims that Hel, his former lover, is not dead but alive in the form of the automaton. Hel had chosen Fredersen over Rotwang, who never forgave his rival. The Maschinenmensch is ultimately destroyed when the city's rioting workers burn it at the stake.
Walter Schulze-Mittendorff, who designed the robot costume, described how it was made. He had considered making the robot from beaten copper, but it would be too heavy to wear and difficult to achieve. He then discovered a sample of "plastic wood", a new material which was easy to sculpt into the required shape. Using a plaster body cast of actress Brigitte Helm, Mittendorff cut large chunks of plastic wood, rolled flat with a pin and draped them over the cast, like pieces of a suit of armour. The resulting costume was then spray-painted with cellon varnish spray mixed with silvery bronze powder which gave it the convincing appearance of polished metal. The description in the original film script makes an analogy to an Egyptian statue.
The 2010 restoration of Metropolis revealed a previously unseen scene where Rotwang confides his plans to the robot. The shot is unusual because it reveals part of the back of the robot, namely the back of her head and shoulders.
The cast was made while Helm was standing up, making movements such as sitting down difficult and uncomfortable. According to actor Rudolf Klein-Rogge, it was tight and confining, pinching and scratching the actress despite many attempts by the stage hands to file away all sharp edges. People took pity on Helm and slipped coins into slots in the armour, which she collected to buy chocolate in the canteen. The scene where Rotwang presents his creation to Fredersen took nine days to film in January 1926. Director Fritz Lang shot the scene so many times that an exhausted Helm asked him why she should play the role, when no one would possibly know she was inside the costume. Lang answered, "I'd know." Helm's son believes that Lang was trying to teach the 17-year-old girl some discipline and mold her in his image, almost like the characters she played. The costume allowed little freedom of movement. To help Helm get up from the throne made of sheet metal, a wooden rig was constructed, so that a stage hand could give her a push. Behind the scenes stills show the rig and the hinged plate on the seat.The memorable transformation scene was another early miracle of special effects, using a series of matte cutouts of the robot's silhouette and a number of circular neon lights. All effects were filmed directly into the camera rather than edited separately. As a result, the film had to be rewound and exposed many tens of times over to include the plates showing the heart and circulatory systems as well as cuts between the robot form and Maria showing her gradual transformation.
For years, people have speculated how the light circle animation was made. The magazine Science and Invention suggested at the time that fluorescent lights were used as a purely practical effect, moved up and down manually on invisible wires by stage hands. In later years Lang said in interviews that a brightly lit steel ball used as a pendulum was filmed or photographed with a long exposure time in front of a black screen and was then composited onto the image, though this is not consistent with the multiple exposure method used.
According to the film's set designer, Erich Kettelhut, a glass plate was positioned halfway between the robot and the camera. The silhouette of the robot and throne were carefully drawn onto a piece of plywood to be used as a matte, and using a pair of circular neon lights of a diameter corresponding with the matte's silhouette. By covering the glass plate with grease and filming the moving lights through it the illusion of a light circle moving up and down was created.When playing human Maria's evil twin — the gynoid in human form — Brigitte Helm wore heavy makeup and her expressions, gestures, and poses were exaggerated and jerky compared to Maria's composed and demure demeanor.
The Maschinenmensch is an archetypal example of the Frankenstein creation. Artificial beings with a malevolent nature were popular at the time, as seen in films such as Der Golem or Marcel Lherbier's L'Inhumaine. In a  formerly part of the film, Rotwang explicitly instructs the robot to pervert Fredersen's orders and help bring down his worst enemy, which helps explain her destructive behaviour. Different incomplete restorations of the film made since the original offered different explanations of the robot's behavior. One, for example, says that Rotwang has in fact lost control of the robot and it is not under anyone's control. Others offer no explanation. The 2010 restoration, complete for all practical purposes, depicts Rotwang deliberately instructing the robot Maria, thus finally clarifying the gynoid Maria's motivation.