Expanded Definition of Chromakey

TO:                 Prof. Jason Ellis
FROM:           Ulises Mora
DATE:            10/27/2021
SUBJECT:     Expanded Definition of Chromakey


The purpose of this document is demonstrating the definition of the term “Chromakey,” the use of it in different contexts or scenarios, and my own definition. First, I will compare three definitions from three different sources, including an etymology definition. Then, I will collect some context in which this word is used; the use of this word on different fields in which it can be used; and how they are assimilated for the same function. Finally, I will present my own definition after this whole expanded research of the word.


People might be familiar with the word “Green-Screen,” as Chromakey is the technique that allows the Green-Screen to work. Both words are basically the same, but Green-Screen is the most common term used, while Chromakey is the real-fancy term. According to the Oxford English Dictionary, chromakey is: “A technique or process for selectively combining two different images to form a composite scene by filming in front of a coloured screen or background, used esp. for depicting live action in drawn, modelled, or computer-generated settings” [1]. This means that chromakey allows you to put two different images at once; basically, one project and one background, in which the Chromakey is commonly the background. Regarding its etymology, the definition and interpretation has been maintained since its origins, “1958   R. C. Kennedy & F. J. Gaskins in Proc. IRE 46 1798/1   A new process called ‘Chroma-Key’ is described. ‘Chroma-Key’ is an insetting or matting technique intended for color television which utilizes a highly saturated color background for the inset subject.” [1]. Proving that since 1958, Chromakey remains having the same function as it used to have when it originated. A definition from another source, the Canadian Oxford Dictionary, defined Chromakey as: “a technique or process for selectively combining two video images to form a composite picture, in which all areas of the first image that are of a particular colour or chrominance (usually blue) are detected, and are replaced by corresponding parts of the second image.” [2]. This definition shows more in detail how this process ends up as to what Chromakey is. They mentioned “usually blue,” but along the time, the green color became mostly used. This is because the green color “were generally preferred because they tended to produce less video ‘noise’ and ‘static’ during compositing.” [3]. 


I found three sources in which the term “Chromakey” is used. The first source is a book called Broadcast Journalism, which is about different technical aspects of television and news, including personal and everything related to technology. In a section about the weather forecast, Eadie explains the illusion that they can create with the chromakey, where the audience can see the graphic design created behind the subject that gives the forecast: “The visual aids you see behind them on the screen. In reality, there is nothing behind them in the studio except a green wall. A technology called chromakey inserts the graphics electronically.” [4, p. 639]. Letting us know about the background change process, where everything green is digitally exchanged for another background; in this case, the weather graph that is presented in the weather news, due to the chromakey. 

Through an article from the New York Times, we can assimilate chromakey in the same way, and that the definition and use of this word does not change compared to the previous source. The article talks about a science fair for children that happened in Manhattan during the 90’s, in which one of the expositions involved a special background effect. Leimbach says: “While the child manipulates the cameras, including a chromakey, which can superimpose Mom against a snowy backdrop and create the illusion that she’s flying. The results are then projected onto monitors.” [5]. Again, chromakey is where magic happens to completely change the background and create an illusion for anyone looking at something completely different on the monitor, all due to a completely green setting (mostly.) However, the chromakey does not necessarily have to be used only to exchange one background for another background; this technical tool also allows the background to completely disappear. According to streamscheme.com, a website to help anyone who wants to start streaming, Luci says:” Live-streamers generally use a green-screen to block out their backgrounds entirely, allowing their viewers to see more of their content.” [6]. This means that chromakey is used to make more than just a background. In movies, especially fiction movies, chromakey is presented in scenes where people must levitate something; there is a person disguised completely in green, this person becomes invisible through chromakey, allowing this illusion of levitation to occur.

Working Definition 

After having compared chromakey’s definition, of seeing it in action in different contexts and they are similar; I would define chromakey as the technique of using a monotonous color (specifically green) to change, insert or alter the color to create a desired image or fade the color for digital design purposes for any audience that is going to watch it through the screen. This technique will be very helpful for me when I begin to specialize in animation or film productions in special effects; because the movies contain this process in almost all the scenes, but the audience cannot see this magic illusion.


[1]        “Chromakey” in Oxford English Dictionary, 3rd ed. Oxford, UK: Oxford University Press, June 2011. Available: https://www.oed.com
[2]        “Green-screen” in Oxford English Dictionary, 3rd ed. Oxford, UK: Oxford University Press, June 2011. Available: https://www.oed.com
[3]        “Chroma-key ” in The Canadian Oxford Dictionary, 2 ed. Edited by Barber, Katherine Oxford University Press, 2004. Available: https://www.oxfordreference.com
[4]        William, Eadie, Broadcast Journalism.” 21st Century CommunicationA Reference Handbook, vol. 2, SAGE Publications, 21st Century Reference Series. 2009. pp. 635-642. Available: Gale eBooks
[5]      D, Leimbach, ” For Children,” The New York Times, Aug. 4, 1995. Available: https://www.nytimes.com/1995/08/04/arts/for-children.html?searchResultPosition=1 [6]        Luci, “How to set-up a green screen for streaming [Twitch & YouTube gaming].” Streamscheme, Available: https://www.streamscheme.com/how-to-set-up-a-green-screen-for-streaming-on-twitch

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