Wetterfrosch

Try to present the weather report which is recorded in a TV studio in front of the so-called chroma key background. On the TV screen you can watch the presenter moving before a map of the Czech Republic or forecasting the weather over Europe. This technique of compositing two images together is called colour keying. Two layers of an image are combined into a single resulting one that the TV viewer sees. The keying colour of the background should be present as little as possible in the colour of human skin, so the choice is usually blue or green. At the same time the presenter must not have on the same colour of clothing as the selected key background. The part of body with such colour would merge with the background and become invisible.