All language subtitles for 6. Despill with Operators

In this clip, we're going to take a look at despills with operators.

So much like using expressions to despill an image,

using a combination of different operators to combine and compare

different channels can really help us to optimize our despill.

These operators can then be used to create spill mattes and maps

that help us to really fine tune any additional color correction

that our despilled image may need.

So the following are a few examples of these workflows.

So let's take a look at our script.

So the first one that we have here is with a blue screen,

and I will note that these workflows can be used for

both blue screen and green screen, much like the expressions.

So just swap out the blue for the green and the green for the blue.

Now, I would note that in most cases,

these workflows work best with the ones shown here,

so the blue screen workflow works best for blue screens,

and green screen with the green screen.

Now there are many different versions of this workflow.

This is just a couple.

But slight modifications for every single different

sequence that you have might be needed,

just because your backing region colors might be slightly different than mine,

however this is a really great starting point for you to work with.

So let's take a look at this in depth.

So here we go, so we have shuffled out the blue channel to all the channels,

the green and the red.

We're going to focus on the just the green and the red for a moment.

So we have multiplied out the green and the red by the

luminosity values and plus them together.

Then what we've done is we're going to multiply or we're going to

disable this for a moment and come back to it,

but we have compared this new image against the blue and we're trying to

take the minimal number values of them all combined.

So there we go, the lowest numbers,

and now what we're going to do is we're going to shuffle them together.

So into the one input we're going to keep the red,

green, and alpha, and we're going to take the number two input,

which is going to be the new blue channel,

so this minimum number over here, and it's going to become the new blue channel,

which despills or moves most of the blue.

So this is looking a little bit better already,

and I think we can take it a little bit further than this.

So now that we have despilled this image, let's take a look at what to do next.

So despill the image, compare it against the original,

and that's going to give us our spill matte.

So here we can see where all the spill is appearing,

again, mostly on the back of our car, so this is on our headrests,

a little bit elsewhere as well,

but we're going to use that to color correct that backing region even further.

So desaturate it, 'cause we don't want to accidentally reintroduce that blue,

and then we're going to aggressively color correct.

So I've tried to pick a color that's close to her hair,

again, so that when we pre-multiply this image,

it will pull this color forward in her edges,

rather than the teal color that we had previously.

So here's the previous teal color, and this is what we're going to add to it.

Now we're taking this spill matte, we are color correcting it,

and now it's becoming a spill map, because it's not being applied as a matte,

but rather on an image that is being plus over top of our despilled image.

So there we go.

So this is looking much better already.

So this was it before, this is it after.

Now we can dial it in even further with this multiply

that we were talking about before.

So let's go back up to the multiply,

this is way back at the beginning of our script here,

and turn it on.

So look at that, look,

it's officially gotten rid of this pesky little blue fringe up here.

So let's take a look at what this is doing.

So if I increase this multiply, it's reintroducing the blue.

If I decrease it, it's changing my entire image,

so we don't want to push it too far.. 65 and around

there is probably the magic number.

It's not changing too much of the hair over here,

which is great, however,

keep in mind it is changing the rest of my image quite aggressively.

So we will be isolating this despill and this backing region in our next clip.

So don't worry about it too much, about changing our image,

we're just going to focus on the fringe up here,

but it will have to be modified.

So now let's take a look at what this does or how this stands up

against the previous clips that we despilled the image.

So this here is going to be the newest one that we did.

So here's the operator with the despill and the despill map.

Next we're going to compare this against the expression in the despill.

And if we look at this very close, what a difference.

So, before, so this is the new one, this is the old one.

And then this one here is the keylight with a huecorrect.

So they're very, very close.

Let's just compare them.

So here is the expression, and here is the keylight, both with huecorrect.

So they're very similar.

Keylight with the huecorrect is a little bit better,

but most definitely the newest one that we did has the best results.

So now that we took a look at despill maps and despill mattes,

let's take a look at how that works for a green screen workflow.

So here we go, we got our green screen image,

and we're going to slightly modify this workflow.

So shuffle out the green, shuffle out the blue,

and the red, and we can put some gray tools here.

We'll take a look at that in a moment.

But what's most important is that we're going to

average the blue and the red channels, and then compare them against the green.

So let's just take a look at what that looks like.

So here's our spill matte and it's already despilled

based on the operators that we're using.

And next what we're going to do is we're going to use

this as a mask for our despill.

So here we go.

And we're going to use this despill matte to color

correct and despill our image.

So let's take a look at that.

So here is before and here is after.

And it has a nice transition.

In fact, it's quite a subtle transition.

Take a look at her legs.

It's working much better than it was before.

So let's just pull a quick keylight and see what that does.

So here's a keylight.

Hook this up into the keylight,

since we want to make sure that this is doing inside mask.

Inside mask, and we're going to say 100% on the green,

just make sure it has an alpha, and it does,

and look what it's doing to this edge.

It's almost pushing it too far versus this is the despill here.

So, so much better, much better results with that spill matte,

and just a great overall output.

So the green screen is ready to go on for final compositing at this

point or at least a lot closer than the blue screen.

The blue screen is going to need a little bit more work

just because this color correction here.

So there is it before, starting to affect the entire plate, that's okay.

This is fixable.

So we're going to take a look at that in our next clip,

but already these are looking much,

much better with the fine details in our fringe and the despill.