What is a green screen? How do they actually work? What are the things to take note of when using green screen? Let’s find it out together.
So…… actually what is a green screen? Without looking it up on the internet, you must have thought it literally is just a screen that is green in colour. What is so special about it? In fact, you are only right about 50%.
A green screen is actually a neon-green screen placed in the background of a shot. Green screen is also known as “Chromakey” in the industry. Chroma key involves recording actors and the chosen objects in front of a green screen. The screen is usually either green or blue, hence chroma key is often being referred as a 'blue screen' or 'green screen' effect.
Example 1:
Example 2:
How Does a Green Screen Work?
The process of chroma keying or compositing is carried out by layering two images together.
• The subject in front of the green screen.
• CGI (computer generated Imagery) projected onto the green screen.
The object is shot on a single colour background: green or blue. Then the original background in the editing process is replaced by another, the desired background. This process is called compositing. We usually do it in video editing software like Premiere Pro which is a professional video editing software. Sometimes, we also use a software called Vmix, to chroma key during the production day.
Lighting
• Avoid shadows as it will make chroma key process to be difficult in post-production.
• Avoid using single light
Exposition
• Background cannot be too dark or bright as it will lead to low image quality
The colour of the clothes
• Avoid matching the colours of the clothes and the background on which you shoot your object
Touch Up (Colour Gradients, Position, Scale Size)
• After recording, editor will touch up the footages making sure it blend in, so that it looks more natural
• Adjust the position and scale size of the emcees/actors, make sure it’s rightly placed
To sum it up:
The whole process is
Green Screen Recording > Video Editing Software >Touch Up> Final Output (Production)
Firstly, start recording on a green screen. Then it is projected to video editing software or real time virtual production software which is the place we insert the desirable virtual background. After that, start touching up by adjusting the colour gradient, position and scale size of the emcee. Then only we have the final output. That is all you need to know about green screen as a beginner.
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