When was blue screen invented

The blue screen behind the actress makes it easy to create all of the mattes automatically using optical or digital techniques. The blue screen technique is also used extensively in science fiction films such as "Star Wars" and "Star Trek" to make the spacecraft models look real.

The models are filmed separately on blue backgrounds and then combined in multiple layers to make the final film. Very complex shots with hundreds of layers have been created.

With computers, blue screen shots are even easier because the computer can create the mattes and combine the shots automatically. Many of the links on the next page describe different digital techniques. The next time you go to a movie, you'll understand how they make some of these impossible shots -- but you can still be amazed at how real they look.

For more information on blue screens and other special effects techniques, check out the links on the next page. Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots.

Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. Special Effects. How Blue Screens Work. In the movie ET , how did they make it look completely real when the boys' bicycles began flying? In the movie Star Wars , how did they make it look completely real when Luke flew his X-wing fighter down the trench of the Death Star with Twin Ion Engine fighters in close pursuit?

The X-wing fighter, TIE fighters and the trench were all models In the movie Return of the Jedi , how did they make it look completely real when Leia and Luke were flying at mph on their speeder bike through the forest?

In the movie Back to the Future , how did they make it look completely real when the DeLorean car took off and started flying down a suburban street? Even on the TV news every night, how do they make it look completely real when the weatherperson is standing in front of an animated weather map full of computer graphics?

Static Mattes " ". The original scene: Actors on a plain on a nice day Not very spooky. The sky is matted out with black paper placed over the sky on the camera's lens. The sky portion of the film is not exposed in the first shot. The film is rewound and a dark, cloudy sky is filmed with a matte placed over the previously exposed portion of the film.

When the film is developed, the two shots appear as one. The sky might be computer generated rather than a real, outside sky. Read more: Tupac's rise from the dead was, sadly, not holography. The other name for a green screen — chroma key — gives away how it works.

Video production equipment called a chroma keyer looks at the chrominance data. Pixels that fall in a narrow pie-slice of the hue-saturation circle, centred on the green hue, are deemed to be the green screen. A video switch replaces them with pixels from the background video channel — for example, a weather map. Pixels with all other hues — orange skin tones , red, yellow, magenta and blue — coming from the camera are let through. The resulting video output is the weatherperson superposed in front of the weather map.

Blue screens work almost as well. Because green and blue are both well away from orange-red on the hue circle, both are suitable for chroma-keying people.

If Kermit needed to be keyed on top of a background a blue screen would be essential, whereas Superman needs a green screen. Film-based compositing methods preferred blue screens, due to the availability of blue-sensitive films. Green screen works slightly better for video as there are more green-sensitive pixels in common camera designs than red or blue. And blue coloured clothes are harder to avoid than green ones.

Green screen, also known as chroma key technology, is best known for bringing amazing special effects to the movies.

But how long have green screens been used, and how has the technology changed? Screens were used to produce special effects even back in the days of the theater. Backdrops could be painted on curtains and dropped behind the actors to give the impression of time and place. When movies came into vogue, directors and cinematographers experimented with different techniques to create similar backgrounds and effects.

At first, directors used double exposures. They blacked out parts of a set, ran the film through the camera again, and thus recorded new footage on the blacked-out parts—an example of this effect is the fields rushing by a window in the film The Great Train Robbery. But the use of black screens could only do so much. With the arrival of color film, more effects became possible with blue screen.

Actors performed in front of a blue-colored screen.