Matte (filmmaking)

In film and stage, mattes can be physically huge sections of painted canvas, portraying large scenic expanses of landscapes.

Other shots may require mattes that change, to mask the shapes of moving objects, such as human beings or spaceships.

Originally, the matte shot was created by filmmakers obscuring the background section on the film with cut-out cards.

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.

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.

In the 1960s, Petro Vlahos refined the use of motion control cameras in bluescreen and received an Academy Award for the process.

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 planning began for The Empire Strikes Back in 1980, for which Richard Edlund received the Academy Award for his work to create an aerial-image optical printer for combining mattes, though this process was still 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.

[3] As of 2020[update], nearly all modern mattes are now done via digital video editing, and the compositing technique known as chroma key - an electronic generalization of the bluescreen - is now possible even on home computers.

The in-camera matte shot, also known as the Dawn Process[4] is created by first mounting a piece of glass in front of the camera.

This test footage clip is used as the reference to paint the background or scenery to be matted in on a new piece of glass.

The live action part of the glass is painted black, more of the test footage is then exposed to adjust and confirm color matching and edge line up.

The flat black paint put on the glass blocks light from the part of the film it covers, preventing double exposure over the latent live action scenes from occurring.

Walt Disney used the technique extensively in Snow White and the Seven Dwarfs in order to make the human characters' motions more realistic.

A digital variant of rotoscoping exists today, with software helping users avoid some of the tedium; for instance, interpolating mattes between a few frames.

Unfortunately, achieving this algorithm is impossible due to the loss of information that occurs when translating a real-world scene into a two-dimensional video.

[citation needed] There also exist machine learning tools that can pull mattes with the assistance of a user.

Using the differences between the backgrounds of the two images, McGuire et al. are able to extract a high-resolution foreground matte from the scene.

This method still retains some of the shortcomings of compositing techniques - namely, the background must be relatively neutral and uniform - but it introduces several benefits, such as precise sub-pixel results, better support for natural illumination, and allowing the foreground to be the color that a compositing technique would identify as part of the background matte.

[citation needed] Thus, in "masked widescreen" an image with an aspect ratio of 1.85:1 is created by using a standard, 1.37:1 frame and matting out the top and bottom.

If the image is matted during the filming process it is called a hard matte due to its sharp edge.

[citation needed] In video, a similar effect is often used to present widescreen films on a conventional, 1.33:1 television screen.

The picture is "pushed" farther back on screen and thus made "smaller", so to speak, so that, in a widescreen film, the viewer can see, on the left and right of the picture, what would normally be omitted if the film were shown fullscreen on television, achieving a sort of "widescreen" effect on a square TV screen.

In letterboxing, the top of the image is slightly lower than usual, the bottom is higher, and the unused portion of the screen is covered by black bars.

"[citation needed] A "garbage matte" is often hand-drawn, sometimes quickly made, used to exclude parts of an image that another process, such as bluescreen, would not remove.