Color Keying technique (Also called as chroma key)

How often did you get stunned with your favourite hero flying or floating in the sky? Ever thought of how harrypotter fly high with his broomstick? All this is nothing but the outcome of the color keying technique!

Color keying is a method of removing a particular colour from a video. Suppose you are wearing a dress completely red in color covering full body except your head. If i take a video of your complete body and key off the red colour, what i get in the screen is the MAGICAL you! Your head floating without your body! Did you get what does color keying mean? Green and blue are the most commonly used color for keying off.

Now, how does this technique make someone float in the sky? Take a video of the sky where you want someone to float. Take another video of somebody making actions in a room with a unique color as his background screen. Now open up a video editing software ( I usually use Adobe after effects to do this). Key off the color in that background screen and layer this video to the sky video ( If you do not understand about the layering and video editing stuff, its OK! Just get the idea as of now. This layering is a simple process called as compositing.) You will see the guy making those actions in the sky. Color keying is as simple as that!