Green screen is the most widely used chroma keying technique for visual effects in movies.
First of all, another color is used. That is the blue screen. Blue screen is sometimes used to capture movie scenes. But its usage is very less.
The reason green screen is most commonly used is because of the color filter on the camera sensor. A camera’s sensor consists of numerous tiny photoreceptors that capture images simply by detecting brightness values. Above these receptors for color detection there is a filter layer to detect the three colors RGB or Red, Green and Blue. The sensor of the camera detects the values of these basic three colors and produces colors by combining those values.
And among these filters, green filter is 50 percent, blue filter is 25 percent, red filter is 25 percent. Realize that the green filter is present at twice the rate of other colors. So the camera can detect green color very well. Behind this structure of the camera sensor is the sensor effect of our eyes. Our eyes also have a double rate of green color detection sensors. So the camera sensor is made like this.
Green screen removal is easy in editing software. Built in tools are provided for this. By easily removing the background green, the necessary background can be placed there. Moreover, if any other color was used, like orange, red, pink, then it would be opposite. Because, our skin color always falls in some shade of orange, red or pink. Then, if you want to remove that color, some parts of the skin will be removed. So it is not possible to use those colors.
Blue screen is more expensive to use because blue screen requires more lighting. Green is relatively bright so lighting cost is low. In some cases, the light bounces on the green screen and affects the color of the subject, but if it is necessary, the blue screen is used.
