In simple terms, a green screen is a plain green background that is most often used in photography and videography. The main subject is photographed against this backdrop. Then, in real time or in a suitable video editing suite, this background color becomes transparent and only the main subject stands out. The subject can then be layered onto another scene, giving the video a dynamic look. Viola! You may be standing in your empty garage, but it looks like there’s a Ferrari behind you.
A green screen is typically used when people are presenting a video or when you want to magically change the background. They are not required when used for slide-based presentations.
How does a green screen improve your videos?
Imagine this: you are making a video that describes the places you have visited while on vacation. You could make a video of yourself recorded against this type of screen. Then in the video editing software this green background can be removed and it will appear to look like it is live in the actual location. The actual comment may match the background scenes.
This makes the video very interesting to watch rather than having to watch a commentator speak to the camera. Similarly, an entrepreneur promoting his factory and products can have his image overlap with product and factory scenes. These types of techniques allow you to create a variety of impressive composites.
What is green screen made of and how to use it?
The screen is usually a rough, non-reflective piece of green fabric with a uniform color. It should be wide enough to fill the frame length and height. To set the scene, make sure you have the necessary support so that the green fabric stretches evenly, without wrinkles or folds, along the support frame.
The green screen should have a uniform illumination over its entire surface so that it presents a single tone without gradations. The subject stands in front of this green screen that is evenly lit. Lighting on the subject should come from two or 3 different directions and shadows should be avoided as much as possible. Do not hold the subject too close to the green screen or it will turn “greenish” from the reflection of the screen. That’s it. Now go ahead and shoot.
Download your footage to your computer for editing. You will need to apply the video clips to a timeline and then the chroma key effect will be applied. Chromatic keying is the effect used in most videos to make a color transparent and mix two tracks, overlapping one over the other.
Using the eyedropper, you select the green background color and then adjust the color tolerance slider so that the entire green background is transparent. There are other slider options that can be tried to achieve the best overall effect.
Have another clip ready for the background and drag it to the timeline as well. You will see that the subject of the green screen shot now appears in the second sequence you have on the timeline. It is that simple.
Note: while preparing for a green screenshot, be careful that the model does not wear a green dress or with any accessories or embroidery or rings or shoes that may have some shade of green, otherwise these will also become transparent and they will show up as holes! Well, that may be great after all! Experiment and have fun!