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Mattes are used in photography and special effects filmmaking to combine two or more image elements into a single, final image. Usually, mattes are used to combine a foreground image (such as actors on a set, or a spaceship) with a background image (a scenic vista, a field of stars and planets). In this case, the matte is the background painting. In film and stage, mattes can be physically huge sections of painted canvas, portraying large scenic expanses of landscapes. In film, the principle of a matte requires masking certain areas of the film emulsion to selectively control which areas are exposed. However, many complex special-effects scenes have included dozens of discrete image elements, requiring very complex use of mattes, and layering mattes on top of one another. For an example of a simple matte, we may wish to depict a group of actors in front of a store, with a massive city and sky visible above the store's roof. We would have two images—the actors on the set, and the image of the city—to combine onto a third. This would require two masks/mattes. One would mask everything above the store's roof, and the other would mask everything below it. By using these masks/mattes when copying these images onto the third, we can combine the images without creating ghostly double-exposures. In film, this is an example of a static matte, where the shape of the mask does not change from frame to frame. Other shots may require mattes that change, to mask the shapes of moving objects, such as human beings or spaceships. These are known as traveling mattes. Traveling mattes enable greater freedom of composition and movement, but they are also more difficult to accomplish. Chroma key techniques that remove all areas of a certain color from a recording - colloquially known as "bluescreen" or "greenscreen" after the most popular colors used - are probably the best-known and most widely used modern techniques for creating traveling mattes, although rotoscoping and multiple motion control passes have also been used in the past. Computer-generated imagery, either static or animated, is also often rendered with a transparent background and digitally overlaid on top of modern film recordings using the same principle as a matte - a digital image mask. == History == Mattes are a very old technique, going back to the Lumière brothers. Originally, the matte shot was created by filmmakers obscuring their backgrounds with cut-out cards. When the live action portion of a scene was filmed, the background portion of the film wasn’t exposed. Once the live action was filmed, a different cut-out would be placed over the live action. The film would be rewound, and the filmmakers would film their new background. This technique was known as the in-camera matte and was considered more a novelty than a serious special effect during the late 1880s.〔''The Saga of Special Effects'', Fry and Fourzon, pp. 22-23〕 A good early American example is seen in ''The Great Train Robbery'' (1903) where it is used to place a train outside a window in a ticket office, and later a moving background outside a baggage car on a train 'set'. Around this time, another technique known as the glass shot was also being used. The glass shot was made by painting details on a piece of glass which was then combined with live action footage to create the appearance of elaborate sets. The first glass shots are credited to Edgar Rogers.〔 The first major development of the matte shot was the early 1900s by Norman Dawn ASC. Dawn had seamlessly woven glass shots into many of his films: such as the crumbling California Missions in the movie ''Missions of California'',〔''The Invisible Art: The Legends of Movie Matte Painting'' by Mark Cotta Vaz and Craig Barron, Chronicle Books, 2002; p. 33〕 and used the glass shot to revolutionize the in-camera matte. Now, instead of taking their live action footage to a real location, filmmakers would shoot the live action as before with the cut-out cards in place, then rewind the film and transfer it to a camera designed to minimize vibrations. Then the filmmakers would shoot a glass shot instead of a live action background. The resulting composite was of fairly high quality, since the matte line – the place of transition from the live action to the painted background – was much less jumpy. In addition, the new in-camera matte was much more cost effective, as the glass didn’t have to be ready the day the live action was shot. One downside to this method was that since the film was exposed twice, there was always the risk of accidentally overexposing the film and ruining the footage filmed earlier. The in-camera matte shot remained in use until the film stock began to go up in quality in the 1920s. During this time a new technique known as the bi-pack camera method was developed. This was similar to the in-camera matte shot, but relied on one master positive as a backup. This way if anything was lost, the master would still be intact. Around 1925 another method of making a matte was developed. One of the drawbacks of the old mattes was that the matte line was stationary. There could be no direct contact between the live action and the matte background. The traveling matte changed that. The traveling matte was like an in-camera or bi-pack matte, except that the matte line changed every frame. Filmmakers could use a technique similar to the bi-pack method to make the live action portion a matte itself, allowing them to move the actors around the background and scene – integrating them completely. The Thief of Bagdad (1940) represented a major leap forward for the traveling matte and the first major introduction of the bluescreen technique invented by Larry Butler when it won the Academy Award for Best Visual Effects that year, though the process was still very time-intensive, and each frame had to be hand-processed. Computers began to aid the process late in the 20th century. In the 1960s, Petro Vlahos refined the use of motion control cameras in bluescreen and received an Academy Award for the process. The 1980s saw the invention of the first digital mattes and bluescreening processes, as well as the invention of the first computerized non-linear editing systems for video. Alpha compositing, in which digital images could be made partially transparent in the same way an animation cel is in its natural state, had been invented in the late 1970s and was integrated with the bluescreen process in the 1980s. Digital bluescreening began with ''The Empire Strikes Back'' in 1980, for which Richard Edlund received the Academy Award for his work to create a special kind of optical printer for combining mattes, though this process was still partially analog. The first fully digital matte shot was created by painter Chris Evans in 1985 for ''Young Sherlock Holmes'' for a scene featuring a computer-graphics (CG) animation of a knight leaping from a stained-glass window. Evans first painted the window in acrylics, then scanned the painting into LucasFilm’s Pixar system for further digital manipulation. The computer animation blended perfectly with the digital matte, something a traditional matte painting could not have accomplished.〔''The Invisible Art'', Cotta Vaz/Barron, pp. 213, 217〕 In the modern era, nearly all modern mattes are now done via digital video editing and the chroma key technique - a digital generalization of the bluescreen - is now possible even on home computers. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Matte (filmmaking)」の詳細全文を読む スポンサード リンク
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