Original subtitles

In this clip,

we're going to take a look at detailed edge despill with color correction.

So typically, when we were pulling a green screen key,

we pulled the alpha separately from the despill.

This will often leave us with gray edges wherever there is transparency.

Now in previous clips,

what we took a look at was actually color correcting this backing region

to help with this edge detail where it's transparent.

Now unfortunately,

that backing region color correction often would put this

color correction into the core of our image.

Also, if we try to despill the image too far,

then the core of our image might change where we don't want it to.

For example, if we push it too far,

the color of this little girl's face might turn too red,

but it might help our edge details.

So we're going to take a look at a way to pull two separate despills,

the ability to have an overall despill, say,

for the core of our image,

and then add to it just for the transparent edges here at the side.

So let's take a look at our script.

So here's our script, and we have a temp key.

By no means is this final, but it will work for this particular example.

Now the first thing that we're going to look at is pull

a core matte from this final key.

So we're going to add a color lookup tool,

and we're going to try to rid of any gray values.

So in the color lookup tool, under channels,

select alpha, and select the alpha channel over here on the left hand side.

So we're going to take a look at this little girl's alpha.

We're going to try to rid of any of these gray values.

Now before we do that, we're going to set up this curve.

So select this bottom left hand point, hold down shift,

and select this one up at the top as well and hit H.

Now this is going to give us a nice full off curve.

It's not going to actually change our black point or our white point,

but it will just make it more gradual and not such a harsh color correction.

So we can see here already that it has rid of a lot of the gray

values that were in the backing region to begin with.

So we're going to take the left hand side point and we're going to

pull it in until basically we have a really nice,

hard matte.

So there we go, that's a really great, hard matte to start with.

We have a little bit of gray values over here so we can

probably push it just a little bit further.

There we go.

And we're going to go onto the next step.

So next step over here is going to be to invert.

Now the reason that we want to invert here is because we want to

keep the color correction of our backing region and our

semitransparent pixels from here outwards.

We do not want it to affect our core image.

Now in some cases, this matte doesn't go in far enough,

so we need to do a test to see what it does.

So here's our character, and we're going to look at it on a temporary background,

and we have taken the gray tool with the gain and

we have really cranked it down.

So this is representing where our matte currently is,

anywhere that's black outside of here,

it's showing us where all the transparent or semitransparent

pixels are along the edges of our character.

Now we might need to pull it in a little bit further because we aren't

necessarily catching all the semitransparent pixels,

so let's take a look at how we can do that.

So here we go.

We take a look at our key.

We have crunched our core.

We've inverted our alpha.

And now we're going to push it just a little bit further.

So with a blur tool, we can add a small blur.

So there we go, blur it,

and you can see here that it's creating gray pixels again.

So another way that we can isolate those and make a hard matte,

we can use a color lookup again, or you can use a grade tool.

So here, we've gone into it.

Remember, this is now inversed from where it was before.

It's going to push these values in, so that more that we push this up,

the more that it's going to make our matte bigger,

bigger meaning that more of this will be color corrected.

And the closer we bring it to one, then the smaller it's going to be,

and of course we can invert it,

or at least make it smaller than it was to begin with.

So we're going to pull it up here.

Let's do another QC test.

So here we go, here is the character on our temp background.

So this was it before, and this is it now.

So you can see that we're definitely pulling in more to our character with a

little bit of a soft fall off which is also really nice to help blend between

this color correction that we're about to add,

and the core of our image.

So let's take a look at our last step.

So we're going to take this final alpha that we have here and use

it to color correct after the initial despill.

So here is our initial despill,

and we're going to use it to color correct some of this over here.

So you can see there's a bit of a white halo around her arm,

and we're going to correct that.

We'll take a merge tool, we're going to add it right in here,

so that's right after our matte, we're going to draw a garbage matte,

here's our garbage matte,

and I'm just going to draw just a quick one around her arm.

We can revise it later.

So there is our matte.

And we're going to take that and mask it out, so here's our alpha.

And it's only going to color correct here outwards,

and nothing else, 'cause we really don't need anything else either.

So now let's take a look at our despilled image,

into our grade node, and we are going to basically color correct our image.

So let's take a look, so go into your gain,

I'm going to go into this color wheel, so that is control,

click on the little wheel, and I'm going to add some magenta.

If I push it too far, obviously too far,

just a little bit, so let's turn that on and off.

So that's off, and that's on,

and now let's take a look what it looks like when it is pre-multiplied,

so that is with our new correction, that is with it off,

so you can see that it was dark, we still had that halo there,

and there it's looking a lot better.

So dare I say, just a little bit too far,

somewhere around there is a nice finishing touch.

So again, we don't want to push it too far,

just enough to help this edge and make it a little bit cleaner.

So we can extend this up, it's looking pretty good,

and it can be completed with just a garbage matte.

This isn't mandatory for all shots.

Again, it just depends on what your backing region is looking like,

or rather, not your backing region,

but the new background behind your composition.

So we want to make sure that this is a seamless blend

between foreground and background.

Now we will look at a couple different ways,

just to integrate this edge even further in the following module,

but for now we're just going to look at making this

color so it's a little bit more even.

So here is another version that we have done in advanced,

and you can see that we have done it with both arms here,

so it's looking much better than it was before.

So let's just see what that looks like.

So that was before, and this is after,

so we've actually made it a little bit brighter.

Doesn't necessarily need to be that bright, so we can dial this back.

But already, it's looking a lot better on her edges from what it was before.

Before and after.

So let's take a look at what that does for our blue screen.

So here is our blue screen image.

And of course we were having problems with her hair up here at the top,

so there is our pre-malt, and this is our huecorrect.

Let's just turn off that correction for one moment and

take a look at our final output.

So again, we have some blue at the top of her hair still,

but with our correction,

we can bring in some nice color into the top of her hair,

it's working quite well for this contrasty background,

but does not affect the rest of our image,

so that really is the key point,

is that it is not affecting the rest of our image.

There's some garbage mattes.

So again, just isolating where the hair is with a soft matte,

and we are good to go.

So there is some color correction for our fringe of our elements.

That is in addition to our despill,

and it really helped just take it through to final for

final integration into our plate.