How Do Green Screens Work?

Want to transport yourself into a fantasy world or have the background of your video look like your favorite game? Well, all you need is a green screen. 

Green screens are a must-have item for amateur YouTubers and bigtime video producers alike, but if you’ve never used one before you might find them a little confusing. In this article, we’ll be explaining how green screens works and how you can use one as a beginner. 

So, how do green screens work? Well, when placed behind a subject, green screens make the background of the video completely green. Then, during the editing process, the green color is removed from the image or video using a tool called ‘Chroma Key’. 

Once you know how to use the chroma key tool, using a green screen is actually really simple, so let’s look a little more at how Chroma key works. 

Chroma Key Composition Explained 

Chroma key composition also referred to as chroma keying is the process of layering images or videos and separating them based on the colors. It enables a user to remove a particular block of color from an image or video  

Any modern video editing software will have a chroma key tool that will allow you to do this. The tool is most commonly used to automatically separate the background of the image from the foreground so that you can replace the background with an image or video of your choosing. 

As chroma key uses color detection to accurately separate the images, it works best if you have your subject in front of a solid color background when you are filming. Using a solid color will give you clearly defined lines when the subject is separated from the background and this will make it look much more professional. Most people choose to use the color green as a background which is why ‘green screens’ have become synonymous with chroma-keying.  

So, why Green? 

Green is the color most commonly used for chroma keying because it differs most from human skin tones. Since chroma keying is most commonly used to layer human subjects onto different backgrounds, it makes sense to use green. Using green means that none of the subject’s skin will accidentally be removed during the chroma keying process, and you will be left with a subject that is clearly defined.  

If you don’t have anything green to use as a backdrop, the next best color is blue. Many film companies also use blue backdrops for chroma keying, although it’s not as popular as green. As long as your subject isn’t wearing any colors that clash with the color of the backdrop, you should be able to separate them from the image using chroma keying. 

A Step-By-Step Guide to Using A Green Screen

Ok, so now you know how green screens and chroma keying works, you’re ready to get started. Here’s a step-by-step guide to using a green screen that should help you get the best results.  

Step One: Set up Your Screen 

The first thing you’ll need to do is set up your screen. Choose a location where you can spread the screen out so that the fabric is flat and taught.

Wrinkles in the green screen will cause shadows that will create different shades of green. This will make it harder to key them out when it comes to editing so try to ensure that your screen is flat and the color is as consistent as possible. 

You should also make sure that the space you’ve chosen is big enough for you or your subject to move around properly. 

Step Two: Position Your Subject 

Once your screen is all set-up, it’s time to get your subject into position. Where your subject stands is also very important, as they too can create shadows that might affect the quality of your chroma keying. To reduce shadows, position the subject around 3ft away from the screen itself. 

Then position your camera. Make sure that your subject is well framed and that nothing is interfering with the background in any way. Check if you can see any shadows and if you can, try to rectify them before you start shooting. 

Step 3: Record the Video

After that, you can hit record. Whilst you are filming your subject, make sure that they don’t leave the green screen area at any time. 

If the background of the shot isn’t completely green at all times, it can make the edit a lot harder so it’s important that the subject stays in the shot and doesn’t move around too much. 

Step 4: Upload Your Video To Your Editing Software

If you’ve made a video before, this is something you’ll already know how to do. Upload the clips to your editing program of choice and pull the ones you want to edit onto your timeline. 

Step 5: Chromakey Your Clips 

This step is harder to give exact instructions as it depends on what software you’re using. All the software products that I’ve used, including Sony Vegas and Wondershare Filmora, have a chroma key tool that you can use to remove the background from the image. 

To find out exactly how to do it, it’s best to use YouTube and find a tutorial that shows you specifically how to use the chroma key tool on the software that you are using. For example, here is a tutorial for how to use the green screen tool on Wondershare Filmora 9

Once you’ve removed the green from the image, you’ll then be able to make other adjustments such as feathering and thickness that will adjust the look of the lines around your image. 

Step 6: Add Your Effects and Backgrounds 

After removing the green background, you can then replace the background with whatever you want. You can add any image or video. Your editing software may have some preset background that you can choose from if you’re not sure what background to use. 

3 Best Green Screens for Beginners 

As you can see, using a green screen and editing videos is really easy when you have the right equipment. Green screens are generally inexpensive, so if you’re thinking of trying out some green screen edits, it’s best to buy a green screen kit so that you can achieve the best results. Below are our top picks for beginner green screen kits. 

1. Elgato Green Screen Collapsible Chromakey Panel

This green screen panel is a great buy for beginners. It’s easy to use, easy to store, and provides great results every time. The collapsible panel means that there’s no way for the fabric to crease between uses, so you don’t have to worry about shadows. For the price, it really is the perfect item for the job. 

2. Fotodiox Pro Collapsible 2-in-1 Green/Blue Background Kit

This kit is a small and easy to use option for someone who just needs an easy to use background for videos. The kit simply pops up when you want to use it, and there’s no need to worry about large pieces of creased fabric. It’s a little small, but it’s really simple for beginners to use and even has a blue side. 

3. StudioFX 10×20 Chromakey Muslin Backdrop 100% Cotton Machine Washable Green Screen

If you’re on a budget, and you need something simple that will do the job, this muslin backdrop is sure to be just what you’re looking for. This product is no-frills, it’s simply a piece of green cloth. However, if you have somewhere to drape to secure it, it’s really simple to use, and it’s super cheap. 

Leave a Comment