In simple terms, a green screen is a plain green-colored background most commonly used in photography and videography. The main subject is photographed against this backdrop. Then, in realtime or in a suitable video editing suite, this background color is made transparent and the main subject alone is made to stand out. The subject can then be superimposed on another scene, giving a dynamic look to the video. Viola! You may be standing in your empty garage, but it appears as if there is a Ferrari behind you.
Typically a green screen is used when people are presenting in a video or when you want to magically change the background. They aren’t necessary when used for slide-based presentations.
How Does a Green Screen Improve Your Videos?
Imagine this: you are making a video describing the places you have visited on your holiday. You could make a video of yourself shot against this type of screen. Then, in video-editing software, this green background can be removed and you will be featured so as to make it look as if you are live at the actual location. The actual commentary can match the background scenes.
This converts the video into something very interesting to watch instead of having to watch a commentator speaking into the camera. Similarly, a businessman promoting his factory and his products could have his picture superimposed on scenes of the product and the factory. These types of techniques enable a variety of breath-taking composites to be created.
What is the green screen made of and how to use it?
The screen is typically a piece of green, rough, non-reflective cloth with a uniform color. It should be wide enough to fill the frame lengthwise and height-wise. To prepare the scene ensure you have the required support to make the green cloth stretch evenly, without wrinkles or folds, across the supporting frame.
The green screen will need to have even lighting across its entire surface so that it presents one single tone without gradations. The subject stands in front of this green screen which is evenly illuminated. Lighting on the subject should be from two or 3 different directions and shadows should be avoided as far as possible. Do not keep the subject too close to the green screen or she will acquire a “greenish” shade from the reflection of the screen. This is it. Now, go ahead and shoot.
Download your footage to your computer for editing. You’ll need to apply the video clips to a timeline and then the chroma key effect is applied. Chroma keying is the effect used in most videos of making one color transparent and mixing two tracks, superimposing one on the other.
Using the eye dropper, the background green color is selected and then the color tolerance slider is adjusted to make the entire green background transparent. There are other slider options which can be tried out to achieve the best overall effect.
Have another clip for the background ready and drag this to the timeline too. You will see the subject of the green screen shot now appearing across the second sequence which you have on the timeline. This is how simple it is.
Point to note: While preparing for a green screen shot, be careful not to have the model wearing a green dress or with any accessory or embroidery or ring or shoes which may have any shade of green otherwise these too will become transparent and show as holes! Well, that may be cool after all! Experiment and have fun!