Original subtitles

[Autogenerated] in this clip, we're going to create a light rap.

Light rap is a phenomenon that happens when we photograph things,

and brighter areas of the image tend to bleed into

foreground areas of the image.

And this is something that's missing from this render right now.

What we want to do is we want to build a tool that takes

the bright pixels of the background,

allows us to detect the edges of our element,

brighten them and subtract them and add them into the edge

here to give us a more pleasing look.

So let's take a look at how Channel merge can help us do that.

First thing to do is understand that we have this element right here.

We have this helicopter and we have an Alfa Channel,

and it's using this Alfa Channel that we want to do to detect the edges,

to create an edge and to take the background and we're going to

use a Keir Channel merges in a variety of ways to subtract and

combine are different channels.

So let's start this out by going ahead and creating a luminous key.

Even grab Bakir we're gonna attach to our background now the reason we

need to do this is we want to take the bright levels and dark levels of

the background and kind of crunched them down.

And that looks about good.

So let's close that We can always come back to that later.

And now we're going to put a dot note in.

We'll bring this down here.

I liked to do things neat and organized.

Rude.

Fast.

Well, look that up now, this dilate right here.

What it's going to do is we're going to use it to shrink our mask.

So we have this Alfa Channel right here,

and we're gonna shrink it down a little bit like that,

about 3.2 pixels, and then we're gonna make a copy of this.

We're gonna hook it to the same input.

Except this time we're gonna make it a positive 3.2 pixels.

So what we've done is we've taken the original and we've expanded it,

and we've contracted it.

And what we're gonna do is we're gonna grab one of our channel merges,

and we're gonna set this up.

We're gonna put it to let's reverses inputs A and B,

and let's view the results Okay, so right now it's you needing,

and we don't want it to be union.

We actually want to switch it to minus Great.

So, you see, what we've done is we've taken that channel, the two Alfa channels.

We made one bigger one smaller.

And by doing that, we've now created this outline of our helicopter.

We can control each side of the outline with the two functions So

we can do this one which controls the outer barrier or the negative

barrier controls the inner diameter.

What's closed us.

And now I'm gonna put a blur.

No, down this blur node.

It's so we can soften it slightly.

There we go.

All right.

And now let's put a grade right here and this grade node,

and so we can take the gain and weaken.

Brighten it slightly.

Now we're operating on Alfa Channel,

so we have to make sure that our grade is set to operate on the Alfa as well.

That way, we can use this to either brighten or darken her outline.

So now I need to do a couple of things here.

We want to take our grade note and we want to create another another

channel merge because this time I want to take the result of our outline

and stencil it with a inverted version of this.

So what we're gonna do is we're gonna invert this.

So let's create a invert node and we're going to invert our Alfa,

and we're gonna hook this up to our channel merge,

and we're going to switch this to stencil now What?

This is done.

It's copied the outline of our helicopter edge back into here

because through the process of blurring,

we've now gotten a nice inter gradation like that.

But we don't want to add more pixels to the to the background.

We just want to add more pixels to the foreground.

So we need to subtract the original Alfa from this.

And that's exactly what we're doing by stencil ing it like that.

Now we got to come back to our original color key appear blue Mickey,

we're gonna bring that down.

That's just gonna connected up and let's grab a another channel merge,

and we're gonna hook that in two are a side and we hooked the previous channel.

Marge Darby side.

Now,

the idea here is to take what we had Let me put that dot note

back in second view that we're going to take this and we're

going to subtract this from this.

So that way, because lets go back, appear for a minute.

And look, we want to add bright pixels to the bright areas back here.

But if it's in shadow down here, we don't want to add bright pixels today.

That's gonna look really weird by doing this way by

taking a look at the Alfa Channel.

And now because this is black and if we subtract this from the other one,

we can get a much better result now.

Right now, it's doing a union, and we're gonna choose in.

So it is now taken the background and subtracted it from,

or put it into the other image.

And now we have our bright pixels.

Also we need to do now is to combine this with the original

color of the plate so we can use the color information from

the plate as our brightened pixels.

So let's go back to the shuffle copy and hook up a shuffle.

Copy.

Let's use the DOT ____ right here,

and we're just gonna connect this back up to our

original colored plate right up there.

In fact, what's do a little trick here?

I'm gonna hide the input to this dot node and just put on here.

I'm gonna label it as a plate like that.

And now the air goes away, but we're still seeing the plate.

So shuffle copy down here wants to be RGB on input one.

So we go our g b and they were grabbing that Alfa

out of input to see input to Alfa.

Close it off.

Let's view that.

So here's our Alfa.

There's are rgb and we're gonna put a pre mult after that.

So what we've done here is instead of having just Alfa now it is colored

and we're gonna take this and this is what we're going to merge back on

to our plate and when emerging as a plus,

you know, add it on.

So take this, put it down to our promotes,

and let's just kind of just needing this up a little bit like that.

There we go.

Let's take a look.

So here's our helicopter and now here's our light rap.

Now we do have a little bit of a ghosting effect,

and we have to tweak our levels a little bit.

One thing that is important is that you blur the background.

So I'm gonna create a new blur.

We're gonna put it right here on the background,

loom in its and we're going to use the keyboard Cherica Control K,

which is going to clone that blur and then control V paste.

And I have a cloned blur that's going to blur both the color of the

plate as well as this Alfa Channel right here.

And we should just have to do just a little bit of blurring right here.

There we go.

See,

we're trying to get rid of that right there that's

making it look kind of transparent,

about 30 pixels right there and then weaken tone down on the

amount of our glow with the mix right there.

Here we go,

a beautiful late rap created with channel merges again we subtracted

over here to take a dilate to do manual edge detection.

Then we stenciled an invert of it and then we brought in the

background loom in its to create our light rap.

Using channel merges in this way is a very powerful tool.

Remember a channel merge our merge operations that do ____

medical functions and operations on channels.

You'll find them most useful in operating on alphas,

but they can be used for any channel in the image stream.

In the next module, we're gonna look Atmore efficient work flows,

removing channels, packing channels and and working with the copy note.