This is where I will post some tutorials for different aspects of video editing.
Chroma Keying
By Jonah Walker
Almost two years ago, when I was around 14 years old, I became very interested in video production and editing. I had liked making short movies with my friends when I was younger with my dad's compact camera, but I had never really done any special effects. One day I was working on making a slide-show with Windows Movie Maker, just sort of fooling around with what I knew about the program, when I was unable to save my video, because it kept crashing. I called up my friend, who knows a lot about computers and videos, for help. He directed me to the video editing program for Windows called Sony Vegas. I began using it and, at first, I was overwhelmed by all of the features. Eventually, I understood how to do most of the things I could do in Movie Maker, such as slow motion, fading in and out and adding music. Then I discovered the special effects. There are many very interesting effects that you can accomplish with Sony Vegas. One of my favorite effects that you can do is called “Chroma Keying” or more familiarly known as “Green Screening.”
The term Chroma Keying covers the use of many different colors. Green screening is only one form of chroma keying. There is also the less used, but still popular form of chroma keying called blue screening. The reason the colors green and blue are used, instead of other colors, is because they are the colors furthest away from our skin tone. Green is more popular than blue, because it is less common in casual clothing than blue.
The main purpose of Chroma Keying is to isolate a particular object or person in a video so that you can either replace them with a different object, (such as a background or map like on the news) or to remove the object from the shot by replacing it with the same background as in the shot so that they appear invisible or see-through (like with the movie “The Invisible Man”). Many better video editing programs these days include an ability to “Key Out” something by selecting the color of that object and removing it or replacing it with a different video or image. Chroma keying is used in almost all movies, weather forecasts, TV shows, and more these days.
Chroma Keying is fairly simple to do at home. The only two things you need to do the Chroma Key effect are, a computer with video editing software that has the ability to chroma key, and a green screen, sheet or wall with a solid color. The first thing that you need to do to accomplish this effect is think of an idea. A fun and easy idea to practice with is being a weatherman and giving a weather report in front of a giant animated map. To do this you first need to set up your screen or sheet. You need to make sure that it is well-lit and that there are little to no wrinkles in the cloth. This will help you later. You need to have enough room to stand in front of the screen about 3-4 feet, so that when you are being filmed it will add a bit of a blur to the background and make the color of the screen more even. After you have filmed your desired shot, you will need to import your video file into your editing program and apply the chroma key effect. After you do that, a box should come up that will ask you to choose a color to key out. You should choose green screen or blue screen, unless you are using a solid colored sheet or wall, then you should choose to “select color from video” by clicking on the part of your shot where the sheet, wall, etc. appears. After you adjust all of the properties on the effect so that your background is black, you will need to choose a background video or image. If you are doing a weather forecast, then you should be able to find an image or video of a map on the internet to add as your background. Be sure to check and make sure that the video or image you choose is not copyrighted if you plan to use it in a professional video. Finally, after you have added your background image to your video clip, you may need to make just a few adjustments to the chroma key effect so that both you and your background appear clearly. After you have it all adjusted and positioned in the background you are good to go! Add any sound effects, music, etc. that you want and have fun!
I am hoping to be able to pull of a good chroma key effect soon, my only problem is not having enough free wall space to put up my screen and also having a fairly dark house, making it hard to get good lighting.
I am sure, or at least hopeful, that you will be able to use this knowledge to help you make a good video, or maybe just to better your understanding of special effects these days in films and TV.
