How to green screen your webcam and color correct it properly
It is common for streamers to utilize a green screen to free up space from their webcam; to hide a messy background or having the freedom of creating a more appealing background to suit their stream graphics. It can be done if you have great lighting and a proper flat-colored green wall or fabric to cover the whole webcam frame - if not then cut the webcam frame to match the green area.
Once you have the green area well lit you go to your broadcasting software and use the Chroma Key filter to remove the green matching the background. You need to light up both the background and yourself to make this work properly. The chroma key does unfortunately also remove any other green objects and pieces too so you need to consider what you bring onto your stream and what clothes you wear.
Tried showing my viewers a magic trick with the @elgatogaming green screen... pic.twitter.com/wypyO0ohIm— Jonna Mae ? (@themissesmae) November 7, 2018
Most people just set up the green screen and then let it be there, but to give it a final touch you should open the Color Correction filter and try to fade out the green reflections. If you are using OBS then filters are applied from top to bottom and you should make sure to have the chroma key above the color correction to make sure they do not interfere with each other.
As all setups are different they need different color correction touches to give some edge and sometimes you need 2 layers of color correction to fight each other to get the final result you want. If you are wearing something that reflects the green background - such as leather - you may need to take other precautions before it does not remove the reflecting parts of your leather - read on for more information regarding this!
How the chroma key settings work
It is rather easy to find out how to have a proper background and lighting on youtube or by googling it, but they do not properly introduce you to the actual settings and how they work. Let us go through them one by one so you know what settings to tweak to hopefully achieve the best possible background removal.
The first option is Key Color Type with a few color suggestions, but I recommend you take the "Custom" and then select the most average nuanced green you have between the darkest and lightest areas. Chroma Key removed on a nuanced level, and it is therefore way better if you have the middle/median nuance to work with.
The similarity defines what range of nuances the chroma key will subject to. In other words, how different lighting variations it accept of both lighter and darker nuances of the custom selected color. Combined with the following Smoothness option you can decide how many nuances it should fade into to avoid having a sharp edge between similar color nuances like dark green and very dark green.
The next option is rather interesting as Key Color Spill Reduction is how the Chroma Key tries to handle the reflection of the background color onto other objects - such as the leather we talked about. You should play around with this to find out how well it handles in your scenario.
If you have more options like in OBS that have Opacity, Contrast, Brightness, and Gamma - they give you the opportunity to tune whatever is not removed by the chroma key. If your room is overexposed you can turn down the brightness, but I recommend you do this through a color correction afterward to not mess with the chroma key.