The Book on Chroma Keying

Chroma Keying is an old visual effect trick for placing a subject into a completely new scene. Instead of spending large sums of money for highly wrought sets, producers can just opt for green or blue screens, thanks to chroma Keying. Chroma Keying transforms a video footage of a man pretentiously flying in tight harness to a superhero braving the sky to answer a damsel’s cry in distress.

Chroma Keying, otherwise know as blue screen or green keying and color keying, is accomplished by combining visuals from two different sources. The first source is the foreground subject, shot against a blue or green screen. The second source is the background scene and it can be any stock video footage you have of tall skyscrapers in New York or you can cull to recreate the battle of middle earth using CGI (Computer Generated Imagery).

The two frame sources for Chroma Keying are combined, digitally, to replace anything that is blue or green using the analog video during the digital video editing procedure... click here to read more

Top 5 Rotoscoping Software

There are only two things that can make any motion graphic artist flinch and that's rotoscoping and chroma keying. Why? Mainly because both processes are time consuming and arm numbing. However despite all these, rotoscoping and chroma keying still remains to be very important in the industry we move in. Which is why, lately, software companies are launching new products that aim to lessen the pain in rotoscoping.

Here we will talk about the Top 5 best rotoscoping softwares currently available that deliver accurate and fast mattes... click here to read more

There’s such thing as Outsource rotoscoping and chroma keying

The outsourcing industry is booming and it is expected to grow even further in the coming years. Driven by improved yet low-cost telecommunication capacity and the upswing of technology, the outsourcing industry is expected to generate a whopping $ 2.5 billion in the next ten years. Though outsourcing is common for customer services, telemarketing, and such, post production outsourcing is now at its infancy. The widespread popularity of the internet and the need for a higher degree of visual effects technical expertise are the sub-plots of a script that spells the need for outsourcing digital video post production workflow.

Outsourcing is a risk and the best heeded advice for outsourcing is to outsource labor intensive yet simple tasks. For the digital video post production workflow, rotoscoping and chroma keying are the “it tasks” to outsource... click here to read more

Here are a few steps on how to set up a good lighting

Step 1: Light your chroma key backdrop (Green or Blue Screen)

When lighting your chroma key green screen backdrop, make sure the lighting is even with no hot spots or shadows. Your backdrop lights should be located on either the side or on the back of the subject you are taking video or picture of.

Step 2 : Light your foreground subject

You should light the foreground subject using a separate light. Do not use the same light used on your chroma key backdrop for the subject. Though the blue or green must be lit evenly, this is not true for the subject. You can actually light the subject dramatically however the trick is not to screw up the chroma key background.

Step 3 : Neutralize any color cast

Use a soft back-light on each side of the subject to help neutralize the reflective spill from your chroma key backdrop... click here to read more

Some Tips on Successful Chroma Keying

As mentioned earlier, Chroma Keying is a skill on its own that takes a lot of practice to do properly. When done poorly, Chroma Keying looks really low budget and obviously fake. However, there are a couple things that even a first-time "Chroma Keyer" can do that can improve the quality of their work.

Lighting is the most important part of Chroma Keying. You can never be too careful with it. Take extra care properly lighting your background, and use large white cards to bounce light so that you can achieve even illumination across the entire screen. Remember, different degrees of illumination can create color variations that can confuse your digital camcorders.

Also, be aware of the potential for color spill. You will see color spill as a blue reflection off of your backdrop that colors your subject. In this case, double check the lighting on your subject (again, nice even lighting to eliminate shadows) and then have the subject move farther away from the background screen if possible.

Matte sprays can be attained from your local photography store or even art store. These are useful in reducing the reflective properties of your subject (especially if they have a bald head!) and can greatly reduce color spill or color bleeding.

Editor's note: You may also find a video proc amp (short for video processing amplifier) to be useful in controlling color, matching cameras and so forth for getting the best chroma keying results.

Keeping these tips in mind, you should be well on your way to the exciting world of Chroma Keying. Remember, like anything worth doing, practicing your Chroma Key skills will hone them and turn your boring old home videos or wedding footage into exciting, Hollywood-style action!


Source: http://www.signvideo.com

The Blue Screen

Chroma Keying is similar to using a Luminance Key. In Luminance Keying, the brightness level is set and all of the brighter (or dimmer, depending on the wishes of the camera operator) pixels are turned off. Then a second image can be slid in behind the actor that shows through where the pixels have been turned off.

Obviously, a Luminance Key is really only useful when creating greyscale images, such as in black and white imagery.

Chroma Keying works the same way, except it uses a color instead of a brightness level. The reason for this is that there are many more variations of color that can be used as opposed to limited black-white or brightness levels.

Traditionally, this color has been blue. Hence the term, "blue screen". A common color these days is also green, but theoretically any color is possible. Blue is most often used because the most common subjects filmed are people, and flesh tones stand out better against a blue backdrop than any other color. Additionally, when color spill or bleeding occurs, blue is easier to cover up than green or another color.

It important to note that when a color is properly "keyed out", ALL of that color will disappear. If your subject is wearing blue and you are Keying out blue, then the blue your subject is wearing will also Key out. This can leave "holes" in the actor where the background will show through.

In fact, this is exactly how Lt. Dan in the movie, "Forrest Gump" lost his legs during the film. The actor who plays Lt. Dan (Gary Senise) wore a pair of long blue socks, and when the blue was keyed movie magic occurred. His legs simply vanished.

Depending on your equipment, editing software or even personal preference, you can decide the color used for yourself.


Source: http://www.signvideo.com

How Chroma Keying Works?

If you are going to step into the world of Chroma Keying, you need a few things first.

You need foreground footage, for starters. Foreground footage is your subject, and your color screen. You also need background footage, which is the scenery that is going to be replacing the color screen.

The color screen needs to be evenly lit so that it is the exact color all the way across. Shadows caused by poor lighting can wreak havoc on the Chroma Key process. Also, be aware of your foreground subject lighting. It is important to have two separate sets of lights, and to have the subject far enough away from the screen that the foreground lighting will not interfere with the screen lighting in the back.

Once the subject has been properly lit and the background color successfully keyed, it is time to add the new background scene.

When these two are placed together, your actor is suddenly transported from a large blue screen to anywhere you want, the only limits are your imagination, and of course, what kind of film you can get your hands on.


Source: http://www.signvideo.com/

What Chroma Keying Is?

Video Chroma Keying is also known as "blue screening" in the movie industry. You may have seen it in action before, where an actor stands in front of a large blue screen and acts out the scene by himself.

Next, the camera operators slip a background in behind him, making it appear that the actor is bounding from building to building or climbing the side of a volcano in an attempt to destroy an evil ring!

Chroma Keying is a feature that comes with many cameras. That means that you can make your own amazing shots and impossible action scenes in the comfort of your living room.

You should be warned, however, that Chroma Keying is considered a skill on its own right. Correctly keying the color you want to use in order to avoid "color bleeding" can be a tedious and time-consuming process. Also, shooting with a video camera (as opposed to still photography) means that this work needs to be done in real-time, making it even more difficult.

Nonetheless, Chroma Keying can be a great way to add a little excitement to your video footage. Are those home movies of your kids turning into hours of boring footage of them playing in the sandbox? No problem! Next time, Key them into an island in the South Pacific, happily building sandcastles while World War Two rages all around them!