Using a Green Screen With Your Mac

It is cheap and easy to use a green screen to make videos with your Mac in iMovie. A green screen can also help you improve the quality of your online meeting video.

Video Transcript: Hi, this is Gary with MacMost.com. Let me show you how to use a green screen with your Mac. 
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Now I'm often surprised when I hear that people can't or won't use green screen on a Mac because, maybe they can't get one or can't afford one, or they don't know how to use it. Green screens are actually really cheap and you can do it in a variety of different ways. They are really easy to use. You can use them in a few situations. For instance, I'm going to show you how to use them in iMovie but you can also use them for regular online meetings like in Zoom or even in FaceTime. Even situations where there is no green screen functionality a green screen can really help to improve the quality of your video in a meeting.
So first let's talk about what a green screen is. All a green screen is is a field of green behind you while you're on camera. It doesn't have to be some sort of special screen. It can be something very simple. For instance if you want a really cheap one you can just get a piece of green poster. I can search here on Amazon and find a variety of green poster boards but you can probably find one at a nearby store. A lot of times these are used for school projects available in a lot of colors. Just get a green one. Anything that is a solid green color will do. So for instance if you really want to do it cheaply search for green paper roll and you're going to find these rolls of green paper used for a variety of reasons, even for wrapping paper, that are super cheap and you can just tack it to a wall behind you. Don't worry if there is a little bit of a seam. It doesn't need to be absolutely perfect. Just get it as good as you can. Paper works really well because you're not going to get the reflections that you may get, say, on a glossy poster board. 
Of course the classic thing to use is a green bedsheet for a cheap green screen. It's hard to find a bright green bedsheet but if you can or if you already have one you can just hang that up behind you. But, of course, you can also search for green screen and you're going to come up with a variety of different things and they are probably not as expensive as you think. A lot of these are under $40, sometimes even under $20, and they even include all the things you need to kind of hang it behind you. Cheaper ones are probably not going to be very durable but as long as you take care of them they'll be just fine. There are some really good ones that are not very expensive but are still easy to setup and then put away. Search for Green Screen Popup. You're going to come up with some of the things that look kind of like this. They allow you to actually set it up really quickly and then they kind of fold in an interesting way and go into a small container that is flat and then you can just hide it behind something when you're not using it. All you really need is a solid field of green behind you. I even know people that simply paint a wall green if they are going to be using it all the time. 
Now I'm going to talk about lighting a little later on. But you don't need to really do anything special with lighting if you're just using it for meetings or to create fun videos. 
Let's talk about using green screen. I'm going to talk about using it in videos you create and also using it for online meetings. Let's start by talking about videos. In particular I'm going to talk about using iMovie because iMovie has this function already builtin for a long time. So I've shot some green screen video using the green screen that's always behind me and I did it in QuickTime Player. I just, in QuickTime Player, did a new movie recording and used my Mac's camera to shoot this. So it is just me with a green screen behind me. Notice my chair is also green. I'll talk about that a little later too. So I've got this video here and you can see I didn't use any special lighting. I actually had all my lighting turned off for this so you can see what a more typical situation would be like. So everything is not completely easy. It's a little darker here in some of the corners and the chair is a slightly different shade and all of that. But I've got just the standard video. 
Now I'm going to go into iMovie here. I've got a new project. A mistake a lot of people make that makes it seem like it is hard to use a green screen is that they take this green screen video and they drop it into iMovie and then find they can't see any way to set this up as green screen video where it cuts out the background. You have to remember in iMovie there are two layers. There's the main video layer and then there's the overlay layer. If you're using green screen then you want to do that in the Overlay Layer. After all something has to show through where the green is. If you're using it in the main layer there's nothing underneath that. So, I'm going to get rid of that and I'm going to bring in another video clip here. This is just a video clip of a beach. This is the background video. Now I can put green screen video on top of that. So, I'm going to drag in that same video but I'm not going to put it in the main timeline here.  I'm putting it above that other video. So it is the Overly, that second layer. So now you can see I've got the beach there and then the overly cuts away from that. Now I've got the video of me and then it goes back to the beach. I want this to act as a green screen video wherever it is green it is transparent and I can see the beach. So with that selected I want to go to the tool here that's for the video overlay settings. Then I've got several different options. I can cut-away which is what it is doing now. It is cutting away to the overlay and then back. I can also choose Split-Screen or Picture-In-Picture. But you can see here the second option is green or blue screen,. You can do this all with a solid blue screen if you really want. So let's choose the Green/Blue screen here. Now when I move over this section you can see that where it was green, is now transparent and you can see what's behind me. So it is a simple as that. All you need to do is film yourself or an object or anything over a solid field of green and then use it as an overlay in iMovie and set it up to be a Green/Blue screen overlay. 
Now you can do some adjustments. For instance, notice how since the chair is a different shade it really didn't cut it out completely. It's only semi-transparent there. That's okay. You've got cleanup tools here. I'm going to use the Eraser tool here and I'm going to click where the chair is telling it, also cutout this shade of green completely. As soon as I do that you can see it works really well. You can also use this tool here to Crop. So say if there was an object over here to the left that you don't want included. You can kind of crop it away like that. You can adjust all four corners so you can kind of just have the section that is you, if you want, telling it to completely ignore everything outside of this section. So that is handy if say you just have a poster board behind you and your video has lots of other things outside of the green poster board area.
That's all there is to it. Now you've got this green screen video here where you appear to be over this background video instead of what is really behind you. Of course there are green screen functions in other video editing apps as well. Just about anyone will have one. Certainly Final Cut Pro and other apps like that are going to have some sort of green screen function you can use just like this. Sometimes it is called Green Screen, sometimes it is called Chroma Key. 
You can also use a green screen to make the video of you during meetings better. For instance in Zoom you can use the settings here to have the background behind you cutout. This will work even if you don't have a green screen. You can have a potted plant and a bookcase and a picture and all of that and it will use an algorithm to figure out who you are versus the background and cut everything else out. All you need for that is to go to the Background & Effects section here and select a background. So I can select, like, this standard background here. Now what it is doing is trying to figure out what's me, what's the background and cut that out. It's not perfect but it will work and you don't need to setup a green screen. But if you want to improve the video you can put a green screen behind you and the first thing is is it is just generally going to improve having just a solid color behind you that doesn't match any color that you've got on you is going to help its algorithm separate you from the background. But Zoom also has this. I have a green screen checkbox here. This is under Background & Effects in Settings. If you check that it's going to change its algorithm. Instead of trying to cut you out from the background it simply is going to look for the green and cut that out. Now you notice that the quality is a lot better in terms of how well it cuts things out. So this is kind of a way to bring your Zoom meeting quality up to the next level. 
Now this also works with FaceTime. So, for course, normally in FaceTime it is just a picture of you and whatever is behind you. You can't substitute some sort of background. But if you're doing a presentation, so you're going to share your screen like I'm doing right here, then it is going to actually try to cut you out if you use the smaller, like bottom left corner presentations style. I mean you can do that. You can see it puts you in a little circle and not only is the circle a different color than what is behind you, but your head kind of pops out from that circle. So it is separating you from the background just like Zoom is doing. Now there is no checkbox to say I'm using a green screen. But by having a green screen behind you it's going to make it a lot easier for it to cut you out of the background. So even in applications like this, where there is no specific green screen function, being in front of a green screen is going to produce a better quality result than being in front of a whole variety of different objects that may be in your office. 
Now if you want to take your green screen game up to the next level you'll want to think about lighting. So, if you've got light in front of you making you look good and you've got a green screen behind you one of the things that light is going to do is cast a shadow of you onto the green screen so you're going to have two different shades of green. The regular green and the shadow green. You can fix that by having multiple lights in front of you so casting shadows in various different directions to kind of even it out. You can also fix it by having light above, below, or to the sides of the green screen that is behind you shining onto the green screen. So this will take away the shadows and make the green behind you very bright so it is even easier to separate. This is why it is very important to get some sort of material that doesn't have much of a reflection to it. So some sort of soft fabric or one of these green screen materials that is built specifically not to have reflections. Don't worry too much about this if you just want to casually want to use a green screen in meetings or make some fun iMovie videos. But if you're looking to make is just a little bit better some lighting will go a long way. It doesn't have to be super expensive lighting either. There is a lot of cheap options available in Amazon or you can just use regular lamps. Really any kind of lighting is better than no lighting. 
Finally, I know people are going to ask me about my green chair. My green chair is actually a regular black office chair but it's a high back so you can see it over my shoulders. So something like that may not be a problem in a meeting. I mean people assume that you're sitting in a chair. But I certainly thought it was a good idea to try to get rid of the chair when making videos like this. So to do that you can just throw a piece of green fabric over the chair. But I also found that pretty cheaply on Amazon you can find these stretch chair covers. Just search for Stretch Office Chair Cover and you'll find them in a variety of different colors. Look for the ones that cover a chair similar to yours and have lots of different colors and then if you look at the colors you'll usually find one that are various shades of green and such. Then it will help you blend your chair into the green screen behind it. 
That's it! A green screen is really nothing other than any piece of green material that you can put behind you. Make it a little bit better 
with lighting and you can use it in iMove, other video editing apps, and in online meetings.  I hope you found this useful. Thanks for watching.

Comments: 4 Responses to “Using a Green Screen With Your Mac”

Carl

2 months ago

Great video on a timely subject for me, as I am starting on some presentations. Skype does a super job of removing the background and even my chair without the use of any green screen, and provides for user supplied backgrounds. Do you know of any program that provides good background removal in a similar fashion? That would allow recording at various locations without dragging along a green screen. Once again, thanks for a wonderful and informative website.

Gary Rosenzweig

Carl: No. I've seen passable effects like that in Skype and Zoom as long as you don't move too fast and keep the camera completely steady. But I don't know of a stand-alone recording app that does it. Of course another point of a green screen is not needing to go to "various locations" at all.

Brian A. Foster

Thank you for a GREAT podcast on green screens. You quickly addressed just about everything that a neophyte would need to learn about green screens. We're computer users, after all, so learning about how to make or buy cheap green screens, and even how to properly light them, eliminated all of the unknowns and turned a big mystery into a simple set of choices. Again, well done!

Jeff P

Another terrific video from Gary. Thanks!

Using a Green Screen With Your Mac

Comments: 4 Responses to “Using a Green Screen With Your Mac”

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