Videomaker - Natural Transitions

From start to completion, Charlie walks through the basics of achieving a Green Screen effect.

Setting up a Chroma Keying wall like this green screen behind me is one of the holy grails of video production. Sometimes you just want to replace the background with something different. We will show you how to do it. As far as color choices for Chroma Keying go, green is the most popular choice for video. The biggest reason is that the imaging devices using camcorders are more sensitive to green than to red or blue. You could use blue instead but the primary use for blue is tone. Since the blue emulsion layer tone has the finest crystals. Red is generally not used for chroma keying with people because red is too close to a lot of skin colors. A number of different surfaces can be used for chroma keying. The most permanent is a painted wall. A special mat surface paint is available. This makes for very high quality key effects but it works best with an untextured wall. Both fabric and heavy paper also work well although they are better suited as temporary surfaces. However, they are also portable. The prices of fabric and of paper vary with the quality of the materials. A good and reasonably inexpensive example of a fabric surface is a bed sheet. Some editing software title ship with green plastic sheets for chroma keying. This are both temporary and portable but they are often difficult to find on their own. As far as what your talent can wear while performing in front of a chroma key wall the only consideration is to avoid wearing the same color that is on the surface of the wall. That is to say, if you have got a green wall, you probably do not want to wear green clothes unless you are shooting for a comedic effect. For lighting, the basic approach is to use three-point lighting. Higher wattage fixtures are preferred. You will get the best results if you can get the background lit as evenly as possible and to avoid shadows on the surface of the chroma key wall. When you get back to your editing software, the typical approach to creating the actual chroma key effect is implemented by putting the green screen video on the first track and the new background image or video on the second track. Apply the chroma key effect to the first track. Select the green area to be removed and address the control seek at the cleanest key that you can get. Some editing software also has smoothing, feathering or anti aliasing effects to make the finished video look even better. So we hope we have given you all the information and inspiration that you need to do your own chroma key effect. Once you have considered your clothing choices. What kind of background you are using and you get your light setup correctly. It is a lot of fun. Give it a shot. [Demo] www.videomaker.com