Tuesday, 11 December 2012

Green Screen Effect. (Choma key)




Chroma key is a technique for blending two images, in which a colour or a small colour range from one image is removed or made transparent, revealing another image behind it. This technique is also referred to as colour keying, colour-separation overlay, greenscreen, and bluescreen. 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 principal subject is filmed or photographed against a background consisting of a single colour or a relatively narrow range of colours, usually blue or green because these colours are considered to be the furthest away from skin tone. The portions of the video which match the preselected colour are replaced by the alternate background video. This process is commonly known as "keying", "keying out" or simply a "key".

1. Import both your green screen footage (the video containing a green background, or some green elements that you want to replace) and the footage you want to use to replace the green into Final Cut Pro. (File>Import>Files)


2. Drag the video that you want to be the background (the video that will replace the green) onto Video Track 1.

FCP Green Screen Tutorial Step 2

3. Drag the the video with the green screen and place that on Video Track 2 directly above the previous clip.

FCP Green Screen Tutorial Step 3

4. Double click the footage on Track 2 so it displays in the viewer.


5.Go to Effects>Video Filters>Key>Chroma Keyer. This is the tool in Final Cut that will allow you to take out the green (aka, Chroma Key it)

FCP Green Screen Tutorial Step 4

6. Select the Chroma Key tab from the viewer window.

7. Choose the eye dropper tool from the tool palette to elect the green area in the canvas window.

8. Play around with the saturation and color box until you get a result that looks right to you.

9. Click back on the video tab in the viewer window to finalize.

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