How to use Chroma Key

33 %
67 %
Information about How to use Chroma Key

Published on March 13, 2014

Author: cmoriarty


Keying in Premiere: Keying in Premiere A Look into the processes of Keying and Masking Keying: Keying Where did Chroma Keying start The first film to use the chroma key process was The Thief of Bagdad back in 1940. It was invented by Larry Butler, who won an Oscar for it. Sky Captain and the World of Tomorrow (2004) had almost no real sets or props, relying on Chroma Key in every shot. The Movie adaptation of Frank Miller's 300 was filmed almost entirely in Chroma Key. More Examples: More Examples The Star Wars prequels helped pioneer the idea of minimal set design through Chroma Key. The fact that only blue screen was available for A New Hope caused Luke's squadron to be changed from Blue to Red to avoid problems with blue markings. Also in Return of the Jedi , the only reason Luke's new lightsaber is green is because the battle that takes place on Tatooine happens to have a bright blue sky. In some early trailers, Luke's saber is blue, but they chose to change it to green so it would show up against the sky properly. In the original editions of the original trilogy, you'll notice that whenever R2-D2 is in space, his panels are painted black instead of blue to accommodate the chroma key effect. This was digitally fixed years later for the special edition versions. More Examples: More Examples In Chitty Chitty Bang Bang , blue screen was obviously used for the Flying Car scenes. Obvious because you can see blue matte lines around the actors in several shots . The Amazing Bulk is filmed entirely in Chroma Key. Reasons for Chroma Keying: Reasons for Chroma Keying The main reason to use a chroma key effect is to put a subject over any background you desire, sometimes seeming to do the impossible. Examples are flying cars or other objects The ability to “create a set” where budgetary or travel limits exist To be able to talk about particular graphics while standing in front of them i.e weather or traffic reports on the news. The Process Of Keying: The Process Of Keying The principal subject is filmed or photographed against a background consisting of a single color or a relatively narrow range of colors, usually blue or green because these colors are considered to be the furthest away from skin tone. The portions of the video which match the preselected color are replaced by the alternate background video. This process is commonly known as " keying ", "keying out" or simply a "key". The Process Of Keying: The Process Of Keying Processing a green backdrop Green is currently used as a backdrop more than any other color because image sensors in digital video cameras are most sensitive to green, due to the bayer pattern allocating more pixels to the green channel, mimicking the human eye's increased sensitivity to green light. Therefore, the green camera channel contains the least "noise" and can produce the cleanest key/matte/mask. Additionally, less light is needed to illuminate green, again because of the higher sensitivity to green in image sensors. Bright green has also become favored since a blue background may match a subject's eye color or common items of clothing such as jeans. The Process Of Keying: The Process Of Keying Processing a blue backdrop Before digital chroma keying, bluescreening was accomplished using film. The actor or model is separated from the bluescreen and placed into a specially-made "hole" in the background footage. The bluescreen shot is rephotographed through a blue filter, so that only the background is exposed. A special film is used that creates a black-and-white negative image – a black background with a subject-shaped hole in the middle. This is called a 'female matte', similar to an 'alpha matte' in digital keying. The bluescreen shot was then rephotographed again, this time through a red-and-green filter, so that only the foreground image was cast on film, creating a black silhouette on an unexposed (clear) background. This is called a 'male matte'. The background image is then rephotographed through the male matte, and the shot rephotographed through the female matte. These two images combined together creates the final effect. Blue was preferred as a backdrop before digital keying became commonplace because it is further than green in the visual spectrum from red, the predominant color in lighter human skin. The Process Of Keying: The Process Of Keying Major factors The most important factor for a key is the color separation of the foreground (the subject) and background (the screen) – a bluescreen will be used if the subject is predominately green (for example plants), despite the camera being more sensitive to green light. In analog color TV , color is represented by the phase of the chroma subcarrier relative to a reference oscillator. Chroma key is achieved by comparing the phase of the video to the phase corresponding to the preselected color. In-phase portions of the video are replaced by the alternate background video. In digital color TV , color is represented by three numbers (red, green, blue intensity levels). Chroma key is achieved by a simple numerical comparison between the video and the preselected color. If the color at a particular point on the screen matches (either exactly, or in a range), then the video at that point is replaced by the alternate background How to Utilize Keying: How to Utilize Keying In Adobe Premiere Pro CS 5 After importing your shot of a subject in front of the blue or green screen Place the piece of video on the video 2 channel Then place the fill video, or the video you are keying over in the video one channel In the lower left hand corner, click on the drop down arrow next to video effects Then hit the arrow next to keying Then select Ultra key and drop it right onto video channel two on your timeline How to Utilize Keying: How to Utilize Keying In Adobe Premiere Pro CS 5 After you have completed that step, you are ready to key out the green or blue and key in your video Go ahead and select the eye dropper next to the words Key Color Once selected, drag it to the color you wish to key out then click again You should see video under your key source How to Utilize Keying: How to Utilize Keying In Adobe Premiere Pro CS 5 If the key is not clean, start using some of the tools under the effects panel Matte Generation Matte Cleanup Spill Suppression Remember to check the alpha channel to ensure that you have a clean key

Add a comment

Related presentations

Related pages

How To Use Chroma Key effect - Green Screen Software ...

How to Use Chroma Key Software. Even if you are not familiar with the term, you have seen the Chroma Key effect on TV, when actors are shot against the ...
Read more

Chroma key - Wikipedia

Chroma key compositing, or chroma keying, ... Some films make heavy use of chroma key to add backgrounds that are constructed entirely using computer ...
Read more

Final Cut Pro X: Use chroma keys - Apple Support

Apply the chroma key effect. In the Timeline, add the foreground clip (the chroma key clip with the color you want to remove) to the primary storyline.
Read more

How to Use a Green Screen: A Beginner’s Guide to Chroma ...

Chroma key photography, also known as green screen photography, is a process that allows you to replace a solid colored background with a background of ...
Read more

5 Elements of a Great Chroma Key |

5 Elements of a Great Chroma Key ... and the foam keeps the screen from wrinkling when not in use. For small setups, foldable chorma key screens are ...
Read more

How To Use Green Screen in Photoshop (Chroma Key) - YouTube

Chroma key compositing, or chroma keying, is a special effects / post-production technique for compositing (layering) two images or video ...
Read more

How to use Chroma Key Pro – Help Center

Chroma Key Pro mixes two shots together by converting a selected color in the source shot into transparency. Typically, the source is shot with a green or ...
Read more


chroma key green, chroma key blue, best green screen, foam green screen, chroma key paint, chroma key lights, backdrop stands, background stands, green ...
Read more

Wie man Chroma Key-Effect anwenden kann -

Video im Hintergrund ändern - leicht gemacht mit Movavi Video Editor! Das Programm unterstützt Chroma Key - Effect und mehrere Video-Effekte
Read more

Green Screen Tips, Tricks and Materials - Chromakey ...

Green Screen Tips, Tricks and Materials - Chromakey Tutorial Green Screen Systems. ... Cap 4: Iluminar un chroma key - Duration: 8:49.
Read more