Cels '' shows animation cels and their backgrounds being handled. The cel animation process was invented by
Earl Hurd and
John Bray in 1914. The
cel is an important innovation to traditional animation, as it allows some parts of each frame to be repeated from frame to frame, thus saving labor. A simple example would be a scene with two characters on screen, one of which is talking and the other standing silently. Since the latter character is not moving, it can be displayed in this scene using only one drawing, on one cel, while multiple drawings on multiple cels are used to animate the speaking character. For a more complex example, consider a sequence in which a person sets a plate upon a table. The table stays still for the entire sequence, so it can be drawn as part of the background. The plate can be drawn along with the character as the character places it on the table. However, after the plate is on the table, the plate no longer moves, although the person continues to move as they draw their arm away from the plate. In this example, after the person puts the plate down, the plate can then be drawn on a separate cel from them. Further frames feature new cels of the person, but the plate does not have to be redrawn as it is not moving; the same cel of the plate can be used in each remaining frame that it is still upon the table. The cel paints were actually manufactured in shaded versions of each color to compensate for the extra layer of cel added between the image and the camera; in this example, the still plate would be painted slightly brighter to compensate for being moved one layer down. In TV and other low-budget productions, cels were often "cycled" (i.e., a sequence of cels was repeated several times), and even archived and reused in other episodes. After the film was completed, the cels were either thrown out or, especially in the early days of animation, washed clean and reused for the next film. In some cases, some of the cels were put into the "archive" to be used again and again for future purposes in order to save money. Some studios saved a portion of the cels and either sold them in studio stores or presented them as gifts to visitors.
Cel overlay A
cel overlay is a cel with inanimate objects used to give the impression of a foreground when laid on top of a ready frame. This creates the illusion of depth, but not as much as a multiplane camera would. A special version of cel overlay is called
line overlay, made to complete the background instead of making the foreground, and was invented to deal with the sketchy appearance of xeroxed drawings. The background was first painted as shapes and figures in flat colors, containing rather few details. Next, a cel with detailed black lines was laid directly over it, each line is drawn to add more information to the underlying shape or figure and give the background the complexity it needed. In this way, the visual style of the background will match that of the xeroxed character cels. As the xerographic process evolved, line overlay was left behind.
Pre-cel animation In very early cartoons made before the use of the cel, such as
Gertie the Dinosaur (1914), the entire frame, including the background and all characters and items, were drawn on a single sheet of paper, then photographed. Everything had to be redrawn for each frame containing movements. This led to a "jittery" appearance; imagine seeing a sequence of drawings of a mountain, each one slightly different from the one preceding it. The pre-cel animation was later improved by using techniques like the slash and tear system invented by
Raoul Barré; the background and the animated objects were drawn on separate papers. A frame was made by removing all the blank parts of the papers where the objects were drawn before being placed on top of the backgrounds and finally photographed.
Limited animation In lower-budget productions, shortcuts available through the cel technique are used extensively. For example, in a scene in which a person is sitting in a chair and talking, the chair and the body of the person may be the same in every frame; only their head is redrawn, or perhaps even their head stays the same while only their mouth moves. This is known as
limited animation. The process was popularized in theatrical cartoons by
United Productions of America and used in most
television animation, especially that of
Hanna-Barbera. The end result does not look very lifelike, but is inexpensive to produce, and therefore allows cartoons to be made on small television budgets.
"Shooting on twos" Moving characters are often shot "on twos". One drawing is shown for every two frames of film (which usually runs at 24 frames per second), meaning there are only 12 drawings per second. Even though the image update rate is low, the fluidity is satisfactory for most subjects. However, when a character is required to perform a quick movement, it is usually necessary to revert to animating "on ones", as "twos" are too slow to convey the motion adequately. A blend of the two techniques keeps the eye fooled without unnecessary production costs.
Academy Award–nominated animator
Bill Plympton is noted for his style of animation that uses very few in-betweens and sequences that are done "on threes" or "on fours", holding each drawing on the screen from to of a second. While Plympton uses near-constant three-frame holds, sometimes animation that simply averages eight drawings per second is also termed "on threes" and is usually done to meet budget constraints, along with other cost-cutting measures, like holding the same drawing of a character for a prolonged time or panning over a still image, techniques often used in low-budget TV productions. It is also common in
anime, where fluidity is sacrificed in lieu of a shift towards complexity in the designs and shading (in contrast with the more functional and optimized designs in the Western tradition); even high-budget theatrical features such as
Studio Ghibli's employ the full range: from smooth animation "on ones" in selected shots (usually quick action accents) to common animation "on threes" for regular dialogue and slow-paced shots.
Animation loops from
Eadweard Muybridge's 19th-century photos. The animation consists of 8 drawings which are "looped", i.e. repeated over and over. This example is also "shot on twos", i.e. shown at 12 drawings per second. Creating
animation loops or
animation cycles is a labor-saving technique for animating repetitive motions, such as a character walking or a breeze blowing through the trees. In the case of walking, the character is animated taking a step with its right foot, then a step with its left foot. The loop is created so that, when the sequence repeats, the motion is seamless. In general, they are used only sparingly by productions with moderate or high budgets.
Ryan Larkin's 1969
Academy Award-nominated
National Film Board of Canada short
Walking makes creative use of loops. In addition, a promotional music video from
Cartoon Network's Groovies featuring the
Soul Coughing song "Circles" poked fun at animation loops as they are often seen in
The Flintstones, in which Fred and Barney (along with various Hanna-Barbera characters that aired on Cartoon Network), supposedly walking in a house, wonder why they keep passing the same table and vase over and over again.
Multiplane process The multiplane process is a technique primarily used to give a sense of depth or
parallax to two-dimensional animated films. To use this technique in traditional animation, the artwork is painted or placed onto separate layers called planes. These planes, typically constructed of planes of transparent glass or plexiglass, are then aligned and placed with specific distances between each plane. The order in which the planes are placed, and the distance between them, is determined by what element of the scene is on the plane as well as the entire scene's intended depth. A camera, mounted above or in front of the planes, moves its focus toward or away from the planes during the capture of the individual animation frames. In some devices, the individual planes can be moved toward or away from the camera. This gives the viewer the impression that they are moving through the separate layers of art as though in a three-dimensional space. The most famous device used for multiplane animation was the
multiplane camera. This device, originally designed by former
Walt Disney Studios animator/
director Ub Iwerks, is a vertical, top-down camera crane that shot scenes painted on multiple, individually adjustable glass planes.
History Predecessors of this technique and the equipment used to implement it began appearing in the late 19th century. Painted glass panes were often used in
matte shots and glass shots, as seen in the work of
Norman Dawn. In 1923,
Lotte Reiniger and her animation team constructed one of the first multiplane animation structures, a device called a
Tricktisch. Its top-down, vertical design allowed for overhead adjusting of individual, stationary planes. The
Tricktisch was used in the filming of
The Adventures of Prince Achmed, one of Reiniger's most well-known works. Future multiplane animation devices would generally use the same vertical design as Reiniger's device. One notable exception to this trend was the
Setback Camera, developed and used by
Fleischer Studios. This device used miniature three-dimensional models of sets, with animated
cels placed at various positions within the set. This placement gave the appearance of objects moving in front of and behind the animated characters, and was often referred to as the Tabletop Method.
Impact The spread and development of multiplane animation helped animators tackle problems with motion tracking and scene depth, and reduced production times and costs for animated works. Walt Disney explained why motion tracking was an issue for animators, as well as what multiplane animation could do to solve it. Using a two-dimensional still of an animated farmhouse at night, Disney demonstrated that zooming in on the scene, using traditional animation techniques of the time, increased the size of the moon. In real-life experience, the moon would not increase in size as a viewer approached a farmhouse. Multiplane animation solved this problem by separating the moon, farmhouse, and farmland into separate planes, with the moon being farthest away from the camera. To create the zoom effect, the first two planes were moved closer to the camera during filming, while the plane with the moon remained at its original distance. This provided a depth and fullness to the scene that was closer in resemblance to real life, which was a prominent goal for many animation studios at the time.
Xerography Applied to animation by
Ub Iwerks at the Walt Disney studio during the late 1950s, the
electrostatic copying technique called
xerography allowed the drawings to be copied directly onto the cels, eliminating much of the "inking" portion of the ink-and-paint process. This saved time and money, and it also made it possible to put in more details and to control the size of the xeroxed objects and characters. At first, it resulted in a more sketchy look, but the technique was improved upon over time. Disney animator and engineer
Bill Justice had patented a forerunner of the Xerox process in 1944, where drawings made with a special pencil would be transferred to a cel by pressure, and then fixing it. It is not known if the process was ever used in animation. The xerographic method was first tested by Disney in a few scenes of
Sleeping Beauty and was first fully used in the short film
Goliath II, while the first feature entirely using this process was
One Hundred and One Dalmatians (1961). The graphic style of this film was strongly influenced by the process. Some hand inking was still used together with xerography in this and subsequent films when distinct colored lines were needed. Later, colored
toners became available, and several distinct line colors could be used, even simultaneously. For instance, in
The Rescuers the characters' outlines are gray. White and blue toners were used for special effects, such as snow and water.
The APT process Invented by Dave Spencer for the 1985 Disney film
The Black Cauldron, the APT (Animation Photo Transfer) process was a technique for transferring the animators' art onto cels. Basically, the process was a modification of a repro-photographic process; the artists' work was photographed on high-contrast "litho" film, and the image on the resulting negative was then transferred to a
cel covered with a layer of light-sensitive dye. The cel was exposed through the negative. Chemicals were then used to remove the unexposed portion. Small and delicate details were still inked by hand if needed. Spencer received an
Academy Award for Technical Achievement for developing this process.
Rotoscoping Rotoscoping is a method of traditional animation invented by
Max Fleischer in 1915, in which animation is "traced" over actual film footage of actors and scenery. Traditionally, the live-action will be printed out frame by frame and registered. Another piece of paper is then placed over the live-action printouts and the action is traced frame by frame using a lightbox. The end result still looks hand-drawn but the motion will be remarkably lifelike. The films
Waking Life and
American Pop are full-length rotoscoped films. Rotoscoped animation also appears in the music videos for
A-ha's song "
Take On Me" and
Kanye West's "
Heartless". In most cases, rotoscoping is mainly used to aid the animation of realistically rendered human beings, as in
Snow White and the Seven Dwarfs, Peter Pan, and
Sleeping Beauty. A method related to conventional rotoscoping was later invented for the animation of solid inanimate objects, such as cars, boats, or doors. A small live-action model of the required object was built and painted white, while the edges of the model were painted with thin black lines. The object was then filmed as required for the animated scene by moving the model, the camera, or a combination of both, in real-time or using stop-motion animation. The film frames were then printed on paper, showing a model made up of the painted black lines. After the artists had added details to the object not present in the live-action photography of the model, it was xeroxed onto cels. A notable example is Cruella de Vil's car in Disney's
One Hundred and One Dalmatians. The process of transferring 3D objects to cels was greatly improved in the 1980s when computer graphics advanced enough to allow the creation of 3D computer-generated objects that could be manipulated in any way the animators wanted, and then printed as outlines on paper before being copied onto cels using Xerography or the APT process. This technique was used in Disney films such as
Oliver and Company (1988) and
The Little Mermaid (1989). This process has more or less been superseded by the use of cel-shading. Related to rotoscoping are the methods of
vectorizing live-action footage, in order to achieve a very graphical look, like in
Richard Linklater's film
A Scanner Darkly.
Live-action hybrids Similar to the computer animation and traditional animation hybrids described above, occasionally a production will combine both live-action and animated footage. The live-action parts of these productions are usually filmed first, the actors pretending that they are interacting with the animated characters, props, or scenery; animation will then be added into the footage later to make it appear as if it has always been there. Like rotoscoping, this method is rarely used, but when it is, it can be done to terrific effect, immersing the audience in a fantasy world where
humans and cartoons co-exist. Early examples include the silent
Out of the Inkwell (begun in 1919) cartoons by
Max Fleischer and
Walt Disney's
Alice Comedies (begun in 1923). Live-action and animation were later combined in features such as
Song of the South (1946),
The Incredible Mr. Limpet,
Mary Poppins (both in 1964),
Who Framed Roger Rabbit (1988),
Cool World (1992),
Space Jam (1996),
Looney Tunes: Back in Action (2003),
The SpongeBob SquarePants Movie (2004), and
Enchanted (2007), among many others. The technique has also seen significant use in television commercials, especially for breakfast
cereals marketed to children to interest them and boost sales.
Special effects animation Besides traditionally animated characters, objects, and backgrounds, many other techniques are used to create special elements such as smoke, lightning and "magic", and to give the animation, in general, a distinct visual appearance. Today
special effects are mostly done with computers, but earlier they had to be done by hand. To produce these effects, the animators used different techniques, such as
drybrush,
airbrush, charcoal,
grease pencil, backlit animation, diffusing screens,
filters, or
gels. For instance, the
Nutcracker Suite segment in
Fantasia has a fairy sequence where
stippled cels are used, creating a soft pastel look. ==Modern techniques==