Original subtitles

In this clip we're going to take at exploring core and fringe mattes.

Now before we really begin,

let's take a look at the difference between core and fringe

mattes and the first is the different names.

So different names for core mattes are a hard matte,

inside matte, and inner matte.

And fringe mattes names are soft matte or gray matte.

So let's take a look at what those look like in our script.

So we're going to take a look at our image down here and the first

thing that you will in our template is that we have a bit of a

pre-processing node and that is the denoise node.

So we want to get rid of that noise in order to pull the best key.

Now there are other pre-processing methods that will not

be reviewed in this particular clip.

If you do want a review of those,

I highly suggest that you take a look at the NUKE Green

Screen Keying Fundamentals Course.

Now I have used two different tools so here I've used the keylight tool for

the fringe matte and the primatte tool for the core matte.

So let's take a look at what these look like.

So here's the keylight and if we go into the alpha,

A for alpha, and turn down our gamma in our lights,

we will see the different variations that it has.

So it's either matte it has 100% black, inside the matte is 100% matte,

but towards our edges we still don't have a solid matte so these are areas

of gray that will need to be refined with our core matte.

So over to our core matte.

So this is quite different.

In fact,

you can see this actually dilated out further than our

fringe matte and we will have to change that.

So inside of our core matte 100% white and outside of it, it is 100% black.

And of course we're going to add the two of those together.

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

So onto another template.

And so here you can notice that I have just a generic tool for the fringe,

the core, combining them,

and then the despill separately and that is because it really

doesn't matter what tools that you use to get those mattes as long

as it has those common characteristics.

So here you're going to notice how I mentioned before that

the despill is separate from the matte.

So I combine the mattes together to get that perfect matte,

hopefully and then we're going to despill it separate.

Now why would we want to despill the image separate,

copy over that funnel matte, and pre-multiply?

Well, we're going to take a look at that in a minute.

Now before we do that,

I did want to note that it is very important that the despill comes from

the original image that has not been pre-processed.

In this case the pre-processing is the denoise.

Denoise will degrade the plate.

It will blur it slightly and it just won't look like the original image.

We will lose that noise so we don't want to do that.

Now despill will be covered in more depth in future modules and clips,

but this is just a brief overview.

So let's take a look at different types of keys and the despills that the pull.

So here let's go back to full color, A, and take a look at our image.

So there we go there.

So let's take a look at first the keylights.

So the keylight, if we look down here in the whites, pulls one despill.

Our primatte pulls quite another here.

It's very pink or magenta.

IBK is almost on the green side and the roto shape

that we pull has no despill at all.

So we're going to combine them together with a keymix tool.

The keymix will allow us to isolate the A input and reveal it where the

matte is and it will reveal the B input everywhere else.

So here is the reddish shape that I have to combine the two of them.

And here is the keymix.

So turn off that overlay cue and we can see the harsh details

between the keylight and the primatte despill.

Now these are not refined alphas so this is really the extreme,

just to show how different the despills can be before refinement.

So if I blur that matte between the two of them,

it does blend a little bit better.

In fact, that's better for our alpha here; however,

we do want to see the very different despills so

we're going to turn that off for now.

Back with the overlay, we're going to introduce next the IBK.

So there is the IBK.

Again, it's quite different than the first two and of course, the roto shape.

Now it's a little bit hard to see so that means that IBK is

not doing a very great despill there,

but we do have a bit of despill differences between

the two of them and those two tools.

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

So I'm going to turn off my overlay and take a look at

those four different keyers plus the rotos.

So I guess a roto really isn't a keyer,

but we're using it to pre-multiply the image.

So if we go into here, it almost looks like a patchwork quilt.

So very different despills.

It's going to look a little bit funny perhaps once

we're working with our final image.

So a better alternative to this is to do one global despill once you have

perfected your alpha and that's why we despill separately from the alpha

in some cases just for more advanced keys.

So let's take a look an example of this workflow.

So if we go down here at the bottom we have a workflow that has the tools that

are visible so here is my image so here's my original image.

I have used a keylight to pull the fringe matte.

I have used a primatte to pull that core,

but you will notice that the core is much larger than my fringe,

which is not good.

So that means that we have to root away at our core a little

bit just to blend it in between the two so we don't really

ruin those nice fine-tuned edges.

So a couple things to look at here are going to be

the different types of erodes.

So let's take a look at our property bin and there are

three different types of erodes.

So if I hit tab and type in erode, you're going to see the erode fast,

the erode filter, and the erode blur.

Now the erode fast is exactly what you expect it to

be; it does a very quick job.

It has very little parameters in it and it doesn't allow

you to fine tune any of those edges.

So let's take a look at that now.

So here is that default 1 again, the erode fast, and if I keep it at 1.

5, so there's 1.

5 and I change it to 2, there's no difference.

So this tool can only erode or dilate at a full

pixel setting and not sub-pixels.

So onto the next one.

So this is the filter erode.

We can see that it has different filters and it can work on

sub-pixels so let's take a look at that image.

So there's 2.

5, there's 3, back to 2.

5, and 2.

So it does erode at sub-pixels, which allows us to really fine tune that image.

So back to 2.

5 and you'll notice it has different filters so the box is the fastest.

Here's Gaussian, it blurs those edges just a little bit more.

So I'm going to leave it at box and I will explain why in a moment.

Now onto the last type of erode.

So let's just type 2 in the property bin and take a look at that one.

So this last one has a blur size.

So it has a blur that is included in it and we can increase the quality,

but it has no filter.

So what I like to personally do is I like to use the one with

the filter and then add my own personal blur.

Again, it doesn't really matter which one you use overall,

which erode you use, as long as it gets the results that you're looking for.

So I've taken that erode.

I've eroded away the image so here is it originally.

I've eroded away and added a blur to it just to

combine the two of them in there.

So let's take a look at those combine mattes.

Take a look at that keylight.

Am I retaining those edges?

Yes, I've retained those edges.

Turn down the light so slam it down in the gamma just

so we can see in those details.

So there's the keylight and there's the combine matte,

retaining those edges which is really nice for a combine matte

and now we can despill the image separately.

So as a brief summary for this particular clip,

we looked at blurring the core matte so that we can blend

it really nicely with our fringe matte.

We also looked at why we would want to combine the

matte separately from our despill.