Chroma key is a one of the technical thing in the video production .

Chroma-key
Chroma key is a one of the technical thing in the video production and photography. It is a special effects and post production technique. There are two types of special effects. Such as,
1. Optical effects
2. Mechanical effects
Optical effects called as photographic effects. Through the optical effects we can create images and film frames photographically.

Through the mechanical effects we can create rain, snow, fog, wind, fire and smoke scenes.
Bullet time, computer-generated imagery (CGI), digital composing, In-camera effects and match moving are some of visual special effects techniques.
Adobe system incorporated, animal logic, Au and Venice, Bird studios and BUF Company are some of the famous special effects companies.
Special effects are often used in the films, video games, music video albums and other commercials.
Post production is a one part of the video production process. Video editing, recording and editing the sound track, adding visual special effects, sound design, sound effect and colour corrections are including in this post production process.
Chroma key also one of the popular post production work in the video production. Films, video games and advertising are mostly using in this Chroma key.
Chroma key generally used green colour and blue colour screen as background for the person or object that is to appear infront of the background scene. During the Chroma key process blue or green background will be replaced by whatever available or suitable background video without any affecting the foreground object.
Chroma key is often referred to as blue screening or green screening. This is a very essential in the Chroma key.

During the Chroma key process we want to consider about following things.
1. Lighting
2. Subject positioning
3. Background
Subject positing is very important in the Chroma key. We want to put the foreground subject as far away from the background. Otherwise it will make shadows on the background.
There are no rules for lighting. Even though we must consider about this light set up also. Lighting is depends on the location and what we are shooting. Here also we want consider about shadows falling on the background. Back light is very helpful light in this Chroma key.
We don’t want to use paper or polyester as a background. Those are very shiny and it will make errors. Background screen should not have any wrinkles. If any wrinkles in the background screen, that will affect things too much.
Chroma key will depend on our location, style, equipment and set up also. Through the Chroma key we can improve our images and videos perfectly and very nicely.
Weather newscast is always using this Chroma key. During the program the news reporter or anchored person stands infront of the blue screen or green screen. Then the computer removes the blue or green colour background and replaces whatever they need according to the news story.
Chroma key have chromatte option also. Ultimate is a one of the blue screen keying. Most of the soap operas use it.
Auto key tracking is help to making natural scenes. Ambitious films and HDTV productions are still having confidence on this auto keying for their commercial success.
Now a day film industries are growing very well and earn lot of money. Film industries are using high quality techniques in their production. Film directors are using this Chroma key to tell their story very clearly and easily. Most of the films and advertisements are using 3D animation and visual effects. Such a way they are using this Chroma key also. Lower budget films also use this Chroma key and give their production perfectly.

Following are some of tips about Chroma key
1. When we are using the blue colour screen as a background the foreground object not to wear blue colour clothes. If foreground object wears blue colour clothes, that clothes will also be replaced with the background video.
2. Eliminate the shadows when we are setting the backgrounds.
3. Proper camera exposure is very important.
4. Use separate lights. (background and foreground)
5. Don’t use paper or polyester as a background.
6. Check the position between foreground subject and back ground.
7. Background screen should not have any wrinkles.
8. Outdoor shooting is better.