How to Use Chroma Keyer

Using the Green Screen Technique

‘The world is but a canvas to the imagination.’

This quote reflects the fact that with a little leap of imagination, you can go to places that never were, do things that were never done and bring your dreams closer to reality.  Unfortunately, imagination without the right tool is limited only to remain its creator's fantasy.  Whether it is the right brush while you paint, or the right software while editing videos, you need the right tools to do the right things.

The Chroma Key Color Transition in Video Edit Magic is one such tool.  Also known as the Green or Blue Screen technique, it can help you create truly startling illusions.  You may never have visited the Taj Mahal or the Pyramids of Egypt but with this technique you can at least make it seem that you actually did.

Basically, in this technique a subject is shot in front of a green or blue screen.  (Any solid color will work, but these two are the most common.)  Video Edit Magic then removes this color from the video clip, and fills in the empty space with the picture from another video clip, or a still picture.  A good example is the weather reports shown on television.  The video is created by combining a video with an animation.  The video shows weatherman standing in front of a green screen while the animation displays maps and graphics.  The green background of the video is replaced by the animation.

Things you need

The beauty of this technique is its simplicity.  To achieve this effect, all you need are 2 videos or images, a green/blue screen and Video Edit Magic.

Green/ Blue Screen

You can purchase a ready made screen.  No matter which color you are using, Green or Blue, care has to be taken that the screen is uniform in color and shade.  You can also make an inexpensive screen by using a table cloth or even a wall that is evenly painted and lit.  Spend some time to remove dirt, discolorations, folds and wrinkles.  Uneven colors in the screen will result in a video with floating objects and blotches.

One cannot conclusively say that the blue color is better than the green color or vice versa.  The choice mainly depends upon the subject (the person or object in the foreground video).  It is important that the subject contains as little of the screen color as possible whether in their clothing or as part of an object.  For example, if the person has blue eyes, choose a green screen.  Another handy hint while deciding the color is analyzing the color scheme of the video which will be inserted as the background.  For example, if the background you are going to insert contains images of the sea, then use a blue screen.  If the background contains an image of a park or trees, use a green screen.  This way you can hide and minimize the impact of the edges that appear due to non uniform or unevenly lit screens.

Proper lighting

Once you have decided on the color of the screen, the next step is to shoot the subject standing in front of it.  If you are aiming for perfection, make sure that the subject has a well defined outline.  There should not be small parts of the clothing or even hair hanging loose as you want a sharp separation from the background.  The camera's focus should be on the subject (and not the background), to prevent a blurry effect.  Be sure no one's clothing matches the background color—if you're using a blue screen, and a man is wearing a blue tie, in the final movie it will seem that he has a hole right through his chest!

The lighting of your background is very important.  It should be evenly lit.  If it is too brightly lit, then some light will reflect off the background producing visible circles in the final combined movie.  Also, make sure that the subject is not too close to the background screen.  This is to avoid shadows, which disturb the uniform color of the background.

Since getting the lighting absolutely right is challenging, the easy thing to do is to shoot outdoors.  The Sun is a great light source, as the distribution is even.  Just make sure that no shadows fall on the screen.

Applying Chroma Key Color Transition

Now, that you have created your video with the green/blue background, the next step is to use the Chroma Key Color Transition in Video Edit Magic.  This transition replaces the green/blue background with another video or image.

Superimposing two videos:

1. Add the video / image with the blue background to the Video 2 track on the Timeline.
2. Add the video / image you want to superimpose to the Video 1 track on the Timeline.
3. Position the Seek Slider so that it coincides with the point on the two videos from which you want the superimposition to begin.
4. Select the Transitions tab in the Collections window.  Right-click on the Chroma Key Color icon and select Add Transition to Timeline.

Configuring Chroma Key Color Properties:

To configure the Transition properties, right-click on the Chroma Key Color Transition in the Transition track of the Timeline and select Transition Settings.  You will see the following window:

1. Select the color that you want to make transparent.  Drag the eye dropper icon from Select Color and move it over the color you want to select.  Alternately, you can also select a primary color to be made transparent from the Primary Color array, or specify the RGB values by entering them in the Red, Green and Blue boxes.
2. It is quite impossible to get an perfectly uniform green or blue color as the background of your videos.  It will typically contain varying shades of green or blue.  To make more shades of the same color as transparent, you can increase the Similarity.  Keep increasing the Similarity gradually until you get a well-defined superimposed image.
3. Click on OK.

A final word

The Chroma Key Color Transition can help you bridge the gap between reality and illusion.  Not only can you superimpose videos of a person against a backdrop, you can also use it to remove or add objects inside a video.  The overall illusions and possibilities offered are so stunning and so vast, that once you are enchanted, you just won’t be able to get over your romance with the Green Screen.

This technique gives you the ability to do the impossible, and most importantly do it with grace.  Like with all creative projects, the overall look of the video will largely depend upon your creativity and attention to detail.

Before starting, do a bit of planning and identify what you are trying to achieve.  Then let the world be your canvas.  After all, imagination takes cues from the real world.

Tips

• You Can Use Vegas Movie Maker, Which is Available free on Internet(Full Version)
• Avoid Shadows on Green Screen to Make Video Attractive
• Use Green Or Blue Screen. Sometimes you can Use Red Screen or Yellow Screen