Part of Lesson Plan: Introduction to Chroma Key

Activity Overview / Details

What is chroma key?

Show the Stargate Studios Virtual Reel 2009  (4 Min)

Discussion:

            Who can describe the process of chroma key?  

Read definition:

Chroma key compositing (or chroma keying) is a technique for compositing two images together in which a color from one image is made transparent revealing another image behind it.

This technique is also referred to as color keying, green screen, and blue screen.

It is commonly used for weather forecast broadcasts, wherein the presenter appears to be standing in front of a large map, but in the studio it is actually a large blue or green background.

The meteorologist stands in front of a blue screen, and then different weather maps are added on those parts in the image where the color is blue.

This also works for green screens.

Blue and green are considered the colors least like skin tone.

Chroma is the Greek word for color. Chrominance or chroma is one of the two components of a television signal. 

The other component is luma, which represents the brightness in an image (the "black and white" or achromatic portion of the image)