ChromaKey
 | ChromaKey | This node provides a very simple chroma key functionality. |
The ChromaKey shader replaces a defined color (or color range) by full transparency.
In the example of the image above green (Hue value 120 in the HSV color model) was replaced. The color that should be replaced is controlled by the Hue property. The property Range defines a tolerance value above and below the Hue value. So the replaced colors have the Hue values from Hue - Range to Hue + Range.
The BrightClip defines a color saturation threshold. Only those colors are replaced which lie above the specified value. (BrightClip corresponds to the Saturation value in the HSV color model.)
The chroma key algorithm used here is very simple and does only provide a 1-bit key. Therefore it is not feasible for professional blue/green-box applications.