Things You Must Know About Chroma Key And Green Screen Footage

Nowadays, you may have noticed wonderful backgrounds in various blockbuster movies. All thanks to the green screen, many filmmakers can create unbelievable scenes that look authentic and realistic.

In the early 1900s, the technique of using a screen for creative visual effects was started. But at that time the blue screen was used instead of a green screen. This is because the blue screen worked smoothly with celluloid film. But over the years, the green screen became more popular with the increasing demand for digital filmmaking. However, the green screen is of no use without an effective chroma key.

What is chroma key? How does chroma key works?

According to any professional green screen studio in the world, chroma key is the time-honoured and commonly used visual effect technique. In short, it involves shooting a scene or subject next to a solid-hued backdrop. In post-production, that particular solid-coloured background is removed and replaced with transparency. Later, the scene or object can be placed against any desired background.

In simple words, the chroma key technique is mainly used for replacing a predefined hue in filmed material and further adds any digital content like maps, graphs and animation to the footage from any other shot. The most commonly used colour in digital video shoot is green.

What’s the purpose of the chroma key?

Chroma key helps combine two different video shots in one frame. Using this technique, all the pixels are replaced with predefined green colour with the content of any other digital content. All thanks to this technique, many Bollywood and Hollywood movies are putting magical scenes like flying in the air, jumping through dangerous cliffs, etc. into their films.

One simple way to use this technique is dressing your actor in green and replacing the green hue with chroma key. This way your subject can be an invisible person in your film. However, in the digital age, particular software can remove the background colour with a transparency channel or alpha channel.

What is the green screen? How does the green screen work?

A green screen is a VFX or visual effect technique of layering two video streams or two images together. If you have ever seen behind-the-scene footage from Hollywood movies, you can sometimes see a good amount of green on their sets.

This green screen helps filmmakers to drop any desired background behind their actors. The green screen is most commonly used in film production or video production. Whenever the desired backdrop is not available, filmmakers use a green screen for creating a fictional location, person/alien, futuristic or historic object into the footage.

Using a chroma key in the green screen studio, mostly a selected color, most often green, is digitally removed and made transparent. After that, the desired image is placed on the transparent area for creating the required effect. This effect can also be used with 3D techniques to create fire, smoke, rain, or any other complex moving shot.

What’s the purpose of a green screen?

While any colour can be used for the background, green is a standard choice due to its strong and distinct nature from any subject placed in front of it.

However, green may not work for everything. For instance, you cannot place a frog against a green screen, as it would disappear. In such a case, you need to use a blue screen for creating the footage.

The basic rule for this is that you must not use any matching colours when creating footage. The background must be different from the colour of the subject. Otherwise, if a person is wearing anything in green in front of a huge green screen, that particular piece of clothing will become transparent from the screen.

How to shoot a green screen scene?

Whenever trying to shoot a green screen scene, you need to plan and visualize how you want the scene to look like. Storyboards and concept of art may be helpful in this process. However, your goal is to figure out what is realistic and not a part of your scene. This simply means that you need to be clear about what things need to be present physically in a scene and what needs to be added later during post-production.

In some cases, you may need some original props on your sets to which your actors may refer to. In some behind-the-scene shots, you may see a tennis ball hanging in front of a green screen set. This is done to provide actors with the right visual reference points.

Even lighting is another major concern. Just think about the right lighting of a character for matching it with the lighting of the background or overall environment. This makes a huge difference in making the final composite while layering everything together, using a chroma key.

But you need to use a clean chroma key to make the subjects or actors appear crisp, well-defined edges to make them appear natural. Sometimes, colour spill, digital artefacts and jittery edges from the green screen may appear. The technical team has to fix it before creating the footage.

Conclusion So, this is how the green screen and chroma key technique works simultaneously. These both work hand-in-hand to provide filmmakers or video makers with an easier way to create the desired scene or effect without much hassle. However, you need to consult a professional video production company to help you create the right image or video for the production of an authentic scene(s).