Note: This is a general guide. There will be more specific guides coming later talking about specific software and the best green screens. This is intended to help you get started.
Many online ESL companies have begun to encourage their teachers to use green screens as an enhancement to their online classroom. However, many people may be unfamiliar with what exactly a green screen is and how to set one up and use it when teaching. Green screens can serve as an extremely versatile tool for you to project a wide range of backdrops and effects that will not only help you to engage your students more easily but, can also help with illustrating different concepts throughout the lesson. The great part of this is that while there can be a small learning curve, mastering the use of a green screen and the various software that it can be used with is something everyone can do. Let’s take a look at what a green screen is and how you can set one up for your online classroom.
What is a green screen?
A green screen is a backdrop made from a light green material that is placed behind you and used in conjunction with a technique known as chroma keying. While I won’t go in-depth into what chroma keying is here, the short version is that this is a method of adding multiple video layers together. This is often used in movies for scenes that would be particularly difficult or prohibitively expensive to shoot in real life and in news broadcasts to change the image behind the anchor or weather forecaster. More recently, green screens have been utilized by the makers of online videos such as those seen on youtube to provide awesome videos at a manageable cost.
The green screen is placed behind you and serves as a placeholder. Later on, usually, the green is overlayed with the desired video or image. This doesn’t have to happen in post-production, however, and this is where using a green screen as an online teacher becomes possible. There are numerous pieces of software that are available which allow you to actively overlay images onto a green screen while streaming video, such as you do when you are teaching a class. Examples of this software include Zoom, which is used by some companies for teaching, ManyCam, and many others.
Why use a green screen in an online ESL classroom?
As described above, using a green screen and the right software will allow you to display any picture, video, or clip art that you can imagine. No more searching for random photos on the internet or trying to put your phone up to the camera to show a picture. You can literally project a giant image behind you. This can come in handy for a multitude of reasons, but, the primary two are that you can more easily keep the attention of younger students who are more prone to losing focus and you can easily illustrate visual concepts. If you are clever, you can even play games with the students that you come up with.
This can be incredibly helpful as you can probably tell. Imagine being able to demonstrate the concept of eating a hamburger to your students by projecting a virtual hamburger into your hands that follows you into your mouth. It can be done with the right software. Maybe you are talking about traveling and the lesson mentions a city such as Paris. Sure, you could describe the city with words and ask the students some questions they may or may not be able to answer. The alternative is that you put yourself in the middle of the Parisian streets and ask your students questions about what they can see in front of them.
An added bonus of this is that you can save money on props as you can quite literally introduce hundreds and thousands of different props through the green screen. This is also a major benefit if you travel frequently enough and have to normally bring props and backgrounds. You can replace all of these with a green screen and a few small LED lights.
What are some things to think about?
The benefits of using a green screen in your online ESL classroom are quite numerous. There are a few downsides that should be mentioned, however. The main one being that the software required to use in conjunction with the green screen can be incredibly demanding on your computer’s resources. If you don’t have enough power then you can expect to crash the program and potentially your class in the process. If you do want to use a green screen in the classroom then you need to make sure you have a computer that is powerful enough. We have a list here of the best computers for ESL teachers that you can use as a guide.
Another downside is that it is very easy to go overboard with the backdrops and the effects. You want to use the green screen to enhance the lesson, however, if you are going overboard you can have the opposite effect and instead cause your students to become distracted. This can be especially a challenge with younger children who may be more interested in the cool cartooney backdrop you have as opposed to learning phonics or proper sentence structure. Finding the right balance takes practice but the best thing to think about when selecting effects and backdrops is whether or not it will further students understanding of the lesson or help to keep their attention focused on you and the lesson.
The final thing is that a green screen setup is going to be a bit more of an upfront investment. Green screens range from cheap thrown together setups to expensive cinema grade packages that can be purchased. Most likely, you will be able to get away with some light green cloth and a few LED lights. However, it may end up being more than what you would spend on a stuffed animal and a noise maker. The thing to remember is that it will give you more versatility and, in the long run, be cheaper than buying tons of different props and always having to change out your backdrop.
How do I use a green screen in an online ESL classroom?
Setting It Up
Setting up the green screen itself is going to be relatively straightforward. You can either get a frame or you can hang it up behind you. I would recommend that you invest in a frame that way you can more easily move the screen around if necessary.
After you have set up the screen, you will want to center in your computer positioning so that your camera completely picks up the green screen. The easiest way to do this is to open up the camera on your computer and make sure that the green screen is centered behind you. Make sure that you can easily sit or stand in front of the green screen and that the camera picks up you entirely and only the green screen in the background. There should be nothing else in the frame. Once the screen is centered, you are ready to go.
Lighting is extremely important when using a green screen. You want absolutely no shadows from you being projected onto the screen or around your body. This can cause the software to key in the image onto the shadow. In short, your face or parts of your body could be replaced with the image or video you are projecting.
The solution for this is to have lighting covering all angles that is evenly distributed in order to eliminate the shadows. You also want to make sure that you are using LED lighting as opposed to something like a fluorescent light which can color you yellow or similar colors. Not only does this create a sort of nicotine staining effect on the background, but it can also tint your skin or clothing to be closer in color to the screen and, again, cause overlap.
The best and cheapest thing is to get three or four small LED lights that you can use to light yourself from the sides and top and one light to place behind you facing up in order to light up the green screen from the bottom up. This will ensure that shadows are eliminated from both yourself as well as the screen. If you have a fluorescent room light you might also think about replacing that with an energy saving bulb that will project a more whitish color.
Software Set Up
The software you use will be dependent on which company you are teaching with and what platform they are using. Some companies have built into their courseware the ability to use green screens. Others are using Zoom to deliver lessons which has a feature allowing you to use a green screen for projecting backgrounds onto. Some companies will advise you to use Many Cam. Others may not want you to use a green screen in the classroom at all, so you want to make sure before you get started with one.
Each piece of software will function differently so you will want to make sure that you are looking into the user guide to get specific details for that software. The main thing is to make sure that you set up the software and test it before you have a class so that you can ensure things aren’t going to go wrong or that your computer won’t crash.
You can use almost any of the millions of images that are out there for projecting as a backdrop or for using as an effect. However, some images certainly work better than others. You want to make sure that you are using HD images that are going to look just as good when blown up behind you as when on your computer screen. This is especially true if you are teaching students in a classroom and you are being projected onto a large screen at the front.
Also, you want to try and go for images that aren’t too busy. The more detail in the image you choose the more likely your students are to get distracted looking at your backdrop and the less likely they are to focus on your words. Of course, if a busy background relates to the lesson then that is one thing but make sure you aren’t going overboard.
Always make sure that the images you are using are appropriate. This doesn’t just mean age level appropriateness but also culturally. There are a great many images that you wouldn’t want to use when working with Chinese students, for example, whether they are children or adults, because they may be deemed inappropriate by various governing bodies within the country. The last thing you want to do is to put something up that you believe to be innocuous when in reality you are setting your students up to lecture you about an issue or to become distracted talking with each other. That is of course unless that is what the lesson calls for.
Try to avoid using copyright images, even if the company doesn’t care. There are plenty of websites that offer free stock photos. Two of the biggest are Pexels and Pixabay. You can easily find almost any photo that you could want on one of these sites.
What are some final thoughts?
While using a green screen certainly isn’t going to be an option for all teachers, it is something that a great many online ESL teachers can use to enhance their classes. It provides a relatively cheap way to add effects, backdrops, and videos to the class that can be used to help students more easily understand challenging concepts or those that are more easily explained visually as opposed to using words. It is also fairly easy to use with a very small learning curve for teachers who may not be comfortable with technology. For many online ESL teachers, a good green screen can be a great investment that will make teaching online a bit easier and a lot more fun.