Green Screen Tips & Tutorials
Chroma key is a technique for mixing two images or frames together, in which a color (or a small color range) from one image is removed (or made transparent), revealing another image behind it. This technique is also referred to as color keying, colour-separation overlay, green screen, and blue screen. The biggest challenge when setting up a green screen is even lighting and the avoidance of shadow, because it is best to have as narrow a color range as possible being replaced. A shadow would present itself as a darker color to the camera and might not register for replacement. This can sometimes be seen in low-budget or live broadcasts where the errors cannot be manually repaired. The material being used affects the quality and ease of having it evenly lit. Materials which are shiny will be far less successful than those that are not. A shiny surface will have areas that reflect the lights making them appear pale, while other areas may be darkened. A matte surface will diffuse the reflected light and have a more even color range. In order to get the cleanest key from shooting green screen it is necessary to create a value difference between the subject and the green screen. In order to differentiate the subject and screen a two-stop difference can be used, either by making the greenscreen two stops higher than the subject or vice versa.
Avoiding Green Screen Mistakes
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