Advanced Green Screen Editing in After Effects

In today’s post, Jeff will talk about advanced green screen editing in After Effects.

Note: remember to watch the video tutorial, we wanted to make it easier for you to follow and understand what Jeff teaches you.

Let’s start!

The tool that you use to pull a key is called Keylight and Keylight is made by this company, the Foundry,as I mentioned earlier.

You can go find Keylight over here on its own if I just type in key in the effects and presets panel. You’ll see down here this Keylight 1.2 is the current version.

keylight 1.2
You can go grab that and apply that to the clip but ultimately you’re going to work with two other effects when you are doing keying.

You’re going to work with the Key Cleaner and the Advanced Spill Suppressor.

Since basically folks at After Effects and folks at Adobe know you’re going to use it sooner or later if you’re going to follow a good work flow when you’re working with color correction they have created a preset, how nice.

The preset is over here under animation presets, image utilities and there’s the preset.  You can’t even read the whole title because it’s so long, it lists all three effects.

Keylight, Key Cleaner, Advanced Spill Suppressor.

Keylight - Preset

Use that instead, you don’t need to use Keylight by itself, use this guy (the preset) instead because it just saves you a couple of steps and also it does kind of a neat little thing, I’ll show you that in a second.

So I’ll double click on that to apply it to this clip , we’ll see all three of them over here notice that the Advanced Spill Suppressor is turned off by default because you save that for later. I think the Key Cleaner should be turned off as well, so I’m going to click away and de-select so if I can turn them off it can turn off that one as well.  I’ll click the de-select, turn off Key Cleaner and close them down for the time being so you don’t have to all this room taken up.

We’ll work with the Keylight here on its own.

There is something else I wanted to say.

Under Advanced Spill Suppressor here there’s two methods

there’s Standard and Ultra

If you choose Ultra then you can pick a Key Color.

Standard & Ultra - Advanced Spill Suppressor

The thing is you want to pick the key color that you use here when you select the key over here.

Rather than manually doing that, it will automatically take whatever color you’ve picked here and put it down here when you use this preset. It’s kind of clever, so that’s the other advantage of using a key to build this preset, rather than doing it one at a time.

Here’s the preset.
Here’s Keylight and Keylight at first glance has got a ton of options particularly when you start opening these things up and you go oh my gosh, how am I supposed to figure out this complex thing.

The answer is don’t worry about it, don’t figure it out because most of these things create more problems than they solve.

The folks at the Foundry may wince when they hear me say that but basically you use this as a basic way to do a really good key.

This is an excellent effect to do keying and I’ll get to the question in a second.  It’s an excellent keying system but you can take the simplified approach and then you use the Key Cleaner and the Advanced Spill Suppressor to take care of that.

Now Szilard is asking me:

Can I show and import the preset into After Effects?

The preset is built in, Szilard asked whether we need to import this preset, it’s built into the current version of After Effects I’m not sure when they started building it in. Probably they started building it in when they put the Advanced Spill Suppressor in After Effects which I think they did with the CC version.

You should have this animation preset in there already so no need to import it. Although you could create it very easily but nevertheless there it is. Okay I hope that answers your question.

Okay so where was I?  We’re going to take the simple approach and I’ll explain some of the things along the way here as to why we want to do that.

The first order of business is to pick the green color and selecting the right color when you’re doing keying is important.  You want the right color to simplify the workflow later.

If you just decide I’m going to pick a color kind of near this person then that maybe good enough but you can check your work as you select the color. The way you do that is you go over to the view here and you go to the dropdown list and you change the status.

select color - change status in view

Don’t worry about the fact that that’s white, we’ll deal with that in a second.
Remember I turned off render over here, then you go get the eye dropper tool to select the color.

You can select the color from anywhere in the entire scene here but we’re going to select it obviously from this image over here.

Now nothing is happening over here right but if I hold on the alt or the option key now ah, and we’re looking at the status view. The status view is an exaggerated view of how well the key is working.

alt option key status view

Black means that that will be transparent which we want, we want the green screen to be transparent.

White means that area will be opaque, that’s the foreground we want it to be opaque.

Grey means that there’s some level of transparency of there which could be just minutely transparent or could be extremely transparent, they don’t give you the choice. It’s just somewhat transparent on a huge range.

So now you take your eye dropper tool with the alter option held down and move around until you get a really good key.  See how it works there.  I’m working right over here and it looks like right about there is the best key because we got a lot of black, a fair amount of white so I click there and that now is our key guide. That’s the color we selected.

selected color
Just as a quick follow up you take a look at the advanced depressor, you notice that color matches that color so it automatically did the work of matching those two colors just as a little aside there.

Here’s the video tutorial


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Okay so now we selected the color and we’re looking at the results here.
You know what?We’re going to do one more thing.

Sorry about this, I forgot to mention the first thing you do is get rid of the junk around the outside here.  So I’m going to change from status view to intermediate result so you can see it better.

You can see purple because that’s the background right. Now I’m going to get rid of this crud by using a garbage man it’s called, sorry I should have mentioned this earlier. With the layer selected we just click the pen tool and the reason you select the layer is if you don’t select layer and you get the pen tool you make a shape and you don’t want to do that.

You make the layer active, get the pen tool and start just drawing here.

Hit click around the outside, then just protect this area and get rid of the crud. You just want to check and see how far my hands move out determine how big the mask can be and notice that I hardly reach out at all which was a purposeful thing.

I can make a mask relatively close to me like this and the purpose of the game is to try and have as little of the green screen as well as the crud here necessary to be cleaned up. We want to have as little here to worry about because the less you have to worry about here, the easier it is to get your key.


I should have mentioned the masking right off the bat that’s the first thing you do, but you can see that doing it out of order is not going to hurt.


Okay now I’m going to go back to my stats.  Notice there are a lot of different views here, none of which are any value except for status intermediate result.
Now this brings up the point of why we’re not using all of the rest of this cool stuff down here. We’re going to use some of the cool stuff but not near all of it.


If you choose what’s called final result (from the view dropdown) then that sort of expects you then to use all this stuff including the Inside Mask, Outside Mask, Foreground Color Correction, Edge Color Correction, Source Crops – all these things down here that are pretty complex and are all kind of pushing and pulling.  They push one way and they pull another way, and then you got to adjust this and adjust this.
You’re kind of tweaking it back and forth to get the best mask.

And that is hard and it’s a lot of manual labor and it’s a lot of like guessing.

Rather than have the final result be your choice here, use what’s called the intermediate result and you’ll get better results.

I hate to tell you it’s weird but that’s how it works.
When you are working with Keylight, let it be the intermediate result and not the final result.

When you’re checking your work, status is the best way to check your work. Status is an exaggerated view of how well your mask is, how well your matte is being created. This is the matte, the part that’s inside the white area, that’s the matte.

If you choose a different view here like screen matte it’s a lot more forgiving. You’ll notice it looks like I did a perfect job there, a little bit of grey showing there and the black all around is perfect right. But in fact if I take a look at the status that gives me a truer look of how well my green screen is working which by the way is working pretty darn well. You hardly ever get a clean matte like this just by selecting a color.

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So please remember this:
That’s the thing, we’re not using the final result that’s just way too difficult to accomplish your task.

Stick for intermediate result when you work with Keylight and use status as a way to check your work most of the time.

Feel free to use the Screen Matte once in a while to kind of check your edges and check the hair and things like that.

That’s also fine when you’re working at it.
So let’s get back to status.

Now that we’ve done this, we need to fix things up.

We want to get rid of the grey and the black.

We want to get rid of the grey and the white.

We want this to be all white, we want this to be all black.

The way you do that is by working on the Screen Matte. This is the screen color which is the green and the screen mat is not here you’re working on the mat.

In between here what are these guys?

Screen Color, Screen Balance, Screen Gain, Despill Bias, Alpha Bias


These are Screen Color, Screen Balance, Screen Gain, Despill Bias and Alpha Bias.

Screen Color is basically saying you picked green but you can expand the chroma a bit to take in more green which is one way of fixing a green screen but it leads to problems when you take a look at the view later.
I suggest you don’t use it.

Screen Gain is one of the things that works with this final result thing.

And then the Screen Balance then looks at the color and then tries to relate the color green versus red and blue.  It sets to default at 50% whenever you use green and it sets to default at 95% when you use blue, that’s just the way the colors work so there’s no more reason to mess with this because it sets to the right value by default depending on whether it’s green or blue.
If I had a blue screen here and picked a blue collar there that would change to 95, so you know that’s the thing with that.

The Depill Bias is the spill I was talking about and Keylight does a really good thing. Keylight when you select the color it makes that color transparent and then it looks for that color on the matte, on the edges of the matte.  When it sees that color (that color green), it converts that color to the default color here – grey.
Any place where there would be like a green halo around you or on your skin, or the edges of your body or whatever it converts that to grey which is a good thing. It makes it so it’s not obvious it’s not necessarily the right color but it’s good enough. This is the soft edge.

That is a good thing, that’s the default behaviour.

You can select a color let’s say go to the skin, pick the skin instead and have the edge not be grey but the color of the skin but that also works to this little final result thing here. We’re going to use the advanced spill suppressor to deal with the spill issues anyways.
We’re accepting the grey default and we’ll deal with the Advanced Spill Suppressor later.

That’s what those guys are all about.  You don’t have to use them.

Now the two big guys that you work with here are Clip Black and Clip White.

Clip Black

What you want to do is you want to tell the key that any place that it sees a little bit of grey here in the black, anything basically what it’s seeing there really is really dark black but not absolute black.
You want to say anything that’ really close to black, make it black.

That’s called the clip black mode, I can open it up that’s just a slider.

Clip Black Mode

As I go from zero and you can go forward a little way I want that grey to go away and look how the grey is going away there. It’s going a little bit forward and that’s plenty. I went forward on 4.8 just based on this particular image here.
That’s the way you get rid of the little bits of dark, dark black that are not really black they’re just dark very dark grey and now they’re black. You’re basically expanding the black.  It’s kind of like how color correction works in some ways.

Clip White
Now we want to talk about clipping the white.

I want to take anything that’s just a light grey, almost white and make it white. To do that I start clipping the white by dragging it to the left and you see that okay we’re getting that pretty well figured out.  And I think that is purposefully viewed to my arm is kicked out.

Clip White
I want to look at my hair, so I do

control plus a couple of times to zoom in

space bar to move around

I want to maintain a little bit of a grey area there because that’s okay, that’s a somewhat transparent, somewhat opaque area and you want it to be that way because that’s kind of the soft edge around the hair.
I think this is going to be fine.

Now we change over to the intermediate result and that shows me against the purple background.

If you look around there that’s reasonably good but maybe the hair is too helmetey, right. You can try to deal with that a little bit by adjusting the amount of clipped white, maybe by making it a little bit less intense.  I think that’s pretty close.
If you look down there you see a wisp of hair down there. I must have had my hair well combed that day, that looks pretty pretty good.

Okay so I’ll do shift/ take a full screen view.

Let’s just zoom in on my shirt for a second and I’ll show you something.
Now if I change to the final result (view), I’m not really sure what’s going to happen but I’m guessing that it will turn splotchy.

Do you see the splotch that showed up there, the little splotch up here, the little splotches there and notice the way the edges changed.  This is the thing about the final result, notice that intermediate result is a soft edge and final result is a harder edge and it kind of has a halo around it.

Save yourself a lot of trouble and use the intermediate result.

Now I’m going to take a look at a couple more things that not necessarily are things I need to do right now but there are two more things that you can do here.

You can have what’s called a Screen Softness and Screen Shrink and Grow.
Normally you would not use these things because you don’t want to mess up your edge too much but sometimes if the edge just needs to softened up a little bit you can soften it here just maybe to about 1 or 2 something like that.

How to use Screen Softness & Screen Shrink & Grow
When you soften it you need to kind of shrink it down ever so slightly. That’s also kind of a way to also fine tune the edges a little bit. Those are the other features that I suggest that you work with.
There are two more things down here and it looks like they’re spelled Despot but in fact it means De-spot.

If you were to go back to the status you might see little spots here.

You can use the Despot black and white to deal with them but I found the Despot thing creates more problems than it’s worth so I don’t use the Despot thing. I think we got a pretty good matte here anyways. That is the intermediate result and I think we’ll call that one done for now.

Thank you for watching this video. My name is Jeff Sengstack an Adobe certified expert and the lead instructor here at If you want to watch this entire video lesson as well as other live classes and After Effects crash courses, then I invite you to check out the Blue Fx After Effects Academy.  Just click the link below this video to find out what we’ve prepared for you in the After Effects Academy.

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Remus Hosu

Remus Hosu

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