http://www.techwench.com/photo-chroma-key-%E2%80%93-going-back-to-basics/
Technology often has a way of passing us by, leaving people in an absolute fog. If you feel that way about the concept of photo chroma key, keep reading to find out what it all means. In simple terms it is referred to as blue screen or green screen and has to do with photography. Barring computers, nothing has probably evolved as much as photography has over the years. Manipulating an image with a plain background using blue and green can be done either by a chemical procedure or by using editing software. It is this manipulation that is called photo chroma key.
