All language subtitles for Advanced Keying Breakdown- ALPHA 1.4 IBK Stacked Technique

hey guys it's Tony Lines

bringing you another tutorial

sorry I've been gone for a little bit

I've actually been traveling and working and such

but I'm gonna try to get back into it

so that I can finish up this advanced king tutorial set

and I should be talking about the last alpha section

today which uh

I'm gonna be going into a little more uh

techniques on how to use a certain tool

in this case is the IBK

and I'm gonna be showing you how I use it and how I

have come to understand it and some techniques

that I use along with it that are a little bit

a little bit better than just the basic way that

I have seen it been used

and I call this the IBK stacked technique

and it's because I stack a bunch of IBK colors together

so let me explain briefly what the IBK

is trying to do

so there's two nodes

and IBK Color and IBK Gizmo

and the color is trying to create a clean plate

out of the image by

kind of like doing a key and then

premulting it and then blurring it

and smudging all the pixels

outwards to fill all the coals in

and creating a

clean plate

and the great thing about this is

it does it every single frame

so what that means is if you have lighting changes

or uneven green screens or what have you

this is probably

the key you're gonna wanna default to

because it uh

it won't matter

it's analyzing at every frame

and creating a clean plate every frame so you

you'll have a pretty good key

uh even if lighting is changing

or you have uneven green screens

and that's because it's

uh generating

a clean plate from the plate

and essentially

it's trying to find the difference between

the clean plate and the original image

which gives you an alpha

it's almost like a really advanced difference man

there are some problems

because the clean plate

by default when you do it usually

gets a little blurry

and some areas get a little messed up

you often see

streaking going on

let's see if I can get to do it yo

you often see stuff like this

where it's just kind of weird leftover artifacts

which will give you a poor key

so let me show you guys

how I do the stack technique or

rather let's show the result

so with the stacked technique

you get a much cleaner alpha channel and the reason

that is is because if you compare the two clean plates

the stack techniques is going to

bring it a little closer to the actual plate

and it's basically not

it's not blurring it as much and it's not

it's taking into account more of the

pixels which are important

that need to be kept

and that makes

the difference from the actual plate a lot less

which means you won't get stuff like shadows

shadows from the green screen

like these areas or noisy bits

a lot of the noises are moved when you do it this way

and it's also gonna clean up a lot of the edges

smooth them out um

and it's worked really well for me

so I kind of

this is kind of my default here

if you will

and it's great for edges

and then you'd want to like stack this with a core mat

and combine it with that to get

to get a good key

so this is difference here

let me show you some more examples uh

so this is Scarlett Johansson from Avengers

so you see with a regular IBK

most people get this um

this kind of grainy

I mean it's a good key

but it's got a lot of like

artifacting and stuff in the green screen

there's a lot of weird

blurriness going on towards the edges

and if you end up doing exact version

it gets rid of all these artifacts and some grain left

but in general

it gets rid of a lot more

and help smooth out some of these edges

and keep a truer value of what the Alpha

should look like right now

I'm just using stills that I pick from the internet

so they're not moving

but you get the idea

so here can be pretty difficult sometimes with IVK

and the reason why is

it can leave you with some of this stuff

which is essentially the hair

is not getting picked out from the

from the clean plate because it is too

similar to the green

so it can't recognize it

and then it can't get rid of it

so there are ways around that in fact

where you can adjust your own IBK color

which will get rid of those hair artifacts see

we'll just get rid of the

extra junk and fill it in with the appropriate color

so in this scenario

there's a lot of like weird noise patterns that

are happening in the green screen

and see the difference

see there was a lot more hair detail

that gets picked up when you do

when you customize your clean plate and get it

as best as you can to looking like

something that has had the foreground removed

and it's just a clean plate okay

and I'm going to move on to the last example

which is this dead guy on the ground

and again another image I grabbed from online

and in this scenario

there was a grade that was causing some

ugly stuff to go on on the left side of screen

and that was because it was a little too blue

I went from blue to green

and the IBK color was kind of just

making a mess of that side

so what you can do is kind of

customize the plate

like I did it I just

graded it down to be kind of a uniform green color

and then it accepted it a little better

cause it was trying to do like two keys

one blue one green or anything

so you can customize place

because we're only using this for the Alpha

so it doesn't really matter what you do for the plate

it's the same as a pre processing the green screen

and in this scenario with a lot of customization

we're able to get all the shadows back

and a lot of detail that we weren't able to get before

so I'll show you

this is a very extreme case

but I can show you how to even get a bunch of details

you wouldn't think you'd normally be able to get

okay so the first thing

you're gonna wanna do is make an IBK color

and choose the correct screen color

in this case green

and by default

the size is 10

and you can see that

if I lower the size and then grow it

the green screen gets a lot blurrier

and essentially gets a lot different

than the original plate

so what we want to do is

not use the size pretty much at all

and I keep my size at 1

and that will hug the edge

of where the green screen

where it thinks the green screen is

what is going to tell you is

if you start patching black

which is going to like erode the

that edge pixel inwards

so what you wanna be doing is picking the green screen

color and then eroding it inwards but in this situation

instead of eroding the green screen

it's eroding your subjects edge inward so and this

scenario here

we have a little antenna

and we can still see it because it is grabbing the

edge of the antenna and eroding that in

still leaving it looking like an antenna

so what can we do

well the next step that I do is go to the darks

and I like to use the color wheel

and this can be kind of confusing but

try and bear with me

if you slide the color with

start shifting colors around one way

you'll see that color start to

start to pop back in

so if you shift it the other way

you'll also notice that the screen screen starts to

get eaten into and kind of gets all crazy goes away

so there's a balance

and what you wanna do is find

you wanna a road

looking at the edge you wanna rode as far in as you can

so in this case when I bring the bread up

it's you wanna bring it to just before

the point where it starts exploding like this right so

right about there

if I go any higher and my green screen kind of explodes

if I go any lower than I'm starting to introduce

too much of the edge of the subject

so there's a little balancing process

so in this case

I can see it's kind of eating in my green screen

so I'll just keep adjusting it until that's kind of

gone there we go

so it's just doing minimal damage now

so after this point

I can't really push anything around

and just to take note

you can shift all the channels around

but in general

once you found that kind of threshold point where

it either explodes or it introduces more edge pixels

once you find that good zone then

you only probably need to adjust a couple of these

adjusting lights is not gonna really

do much of a difference

cause once I start adjusting

it's gonna do the same thing

it's going to blow up like that

but you might be able to tweak it a tiny

bit more with the lights

but in general I kind of just leave it alone

dude just darks

we can see what it does not much

it's kind of shot in the dark

some of the sliders

but it's a little more intuitive than kind of just

punching in numbers here or something

I just slide it until it reaches that good zone

but you can see there's still some edges

so what do we do now

we can start to road

and you'll see

you can road in

and what this is doing is just pushing those pixels

out so that it can grab a better color to start

extending it inwards

and now it looks like the only thing that remains

if you flip back and forth

it is now grabbing from the appropriate green screen

and I know that now it will take that color

and use it to fill in the rest of my image

all the black

so it's gonna take the screen color that's very close

and it's gonna fill a little black left with it

so this is my main I became color

so then I copy and paste it plug it in

and now I change the road

from whatever it was to 0

and I use start using patch black

and here's the key with this

so if I patch black in this first node

it's going to start degrading my image

maybe not at first

but once I start

trying to fill in all these black areas

it's going to look a lot different

essentially

it's kind of it's kind of ruining

it's kind of bleeding into

what I've already worked very hard to keep

seeing these areas here

so you can almost think of it as every time you

copy and paste the node

it's not going to

affect anything that you've already done

and what I mean by that is

all these green pixels

all these green pixels here

they're not going to change once I add a new IBK to it

they're going to just

it's going to just fill in the black like so

so all these pixels are new

and this region

but all these outside remain the same

and so what I'm gonna do is

I'm gonna start with a patch black of one

and I'm just going to

exponentially raise it every time I copy and paste

so I went from 1 to 2 now it's 4

now I'm gonna go to 8

and I basically do this until

all of the black

is gone and at this point

I'm at 16 and then I do 32

and at this point it's so far away

that I might as well just finish it off

there you go so get to a point where you're safe to

continue to extend in this case it was 32 for me

now we have a much better green screen clean plate

there's still some areas like this

I can still see this antenna a little bit

where is it

right there

so what you can do is take the first your first node

which is where it's taking the

the edge that it's going to extend from and you can

kind of continue to adjust that

so I'm gonna push this road a little farther

so you see I went from

here to there

which kind of got rid of that antenna

then so should be gone and it should have

not really done much affect anything else

so now that I have my

great clean plate

I make an IVK gizmo

plug the C input into the color

and the foreground into the green screen plate

change it to the right color

and from here

I usually just look at the alpha

and I click Luminance Match

and what that does is kind of give you back

some lost detail usually

sometimes it makes the edge a little too

like but brings back a little too much

so use it at your discretion

also something to note if you gamma all the way down

on your IBK you're most likely going to get some holes

and I would

be very careful with adjusting the red weight or blue

green weight

but I would suggest tweaking it just a tiny bit

to get rid of those holes if you can

but sometimes you won't be able to

but this is mostly an edge key and not a core key

so you can fill in all the

a lot of those holes with the format so

I generally don't like to bring these past

like point seven

cause then it starts getting crunchy

and that kind of defeats the whole point of the key

as you can see

we went from this alpha to this alpha

which is a lot cleaner

has a lot more detail restored

and we got rid of all these weird

kind of green screen shadows that you probably have to

get rid of some other way or I mean

it saves you a step where you'd have to color correct

this image for instance too much

to get rid of it

see we'd have to crunch these blacks

fairly far in order to

get rid of that image of the artifacting

and that will hurt our edges

it'll hurt I just so if we can find a different way

to get rid of all those artifacting here

where we do our key

then we'll have a much better result

and also get to keep some nice edges

okay so let me do another example with

Scarlett Johansson

I'll make an IVK color

in this case it's blue

and you can see an excellent example of it

taking the wrong pixel and blurring that inwards

so put your size to one

you can see exactly what pixel it's grabbing

in order to do the extend inward

and so now we go to our darks

and we start messing with the sliders

until

here we go the

the blue screen is now starting to

have and employ it on itself

so we bring that back a little bit until just before it

starts exploding and like

you wanna look at areas such as this

where we know that this is the blue screen

and we wanna keep that so it's

it's definitely a balance

cause you can see this area as well

where if we bring it up

we get rid of that area

but we lose

a bunch of this blue screen

so we have to make some exceptions

so I would say right about here

it's probably good amount

because we've kept this blue color and yeah

we still have some edges

but we've we can erode that inwards

and won't be too big a deal so

now that we've adjusted as much as we can

to get as close as we can to the blue screen

now we can start eroding inwards

and we can be pretty generous with that

and when you're roding

you want to look at things like this region here

so the more we road

the more area we get rid of and yeah

I mean this might be okay because it's such a small

tiny area but

you might wanna keep a couple pixels because

believe it or not

that color information can

can really help

because it's going to grab this color information

and extend it very far

and if we lose it

then it has to grab

the nearest color

so that would be somewhere over here over here

and it's so far away from it

that it might start to get all muddy

so in places where you have holes such as that

you wouldn't want to road it to

the point where the hole is gone

you'd want to keep as much as

as much of it as you can

so that it can grab the color and then push it out

so this is looking pretty good it seems to be grabbing

here we go seems to grab an okay areas

so let me take it copy it

then you wanna bring the road down in the patch

black up and you can start at 1

you can probably start at 2

it's not that big a deal

so if we start at 2 2 4

and the computer can usually handle

stacking these things it's not processor intensive

it doesn't change the

timing of the key too much as far as

time takes the render and such

so here we go now it's all gone and I wanna show you

I wanna show the difference

between just leaving in one node

which is here

and actually taking time to clean it up

see all the wrinkles that we can still see in our

our clean version

see all these poles get completely destroyed when we

rode things in too far

change the size all these wires get kind of messed up

things just get really blurry and that's why

there's so much difference

still left over when people do their IBK's okay

so I'm just gonna grab this gizmo

another one and we'll take a look at the Alpha

here we go we got a pretty good result

even the wires are gone at this point

because they were considered blue screen

and all these

all these areas are being kept in the clean plate

as much as they can see it almost seems like this

this object was just completely removed but uh

put the green screen stayed in place

which is exactly what we want

and it's a pretty big difference

it looks a lot better

let me briefly talk about problems that may uh come up

so if you're doing

uh say something like this plate

where there's a lot of hair and there's a lot of wispy

stuff going on

or maybe even a lot of transparency

you're going to notice that

you're going to reach that that threshold

when we're adjusting our darks

it will reach the point where the green screen explodes

but there's still hair

wispy hair that you can see

and so this is one of those

one of those moments

we're gonna have to compromise and just

bring back as much as we can

but we still see that we're going to uh

if we rode this all in

there's still a bunch of hair that

was kind of left behind from this guy's head

which means when it pulls the difference

it will see that

it'll it'll think that it's part of

the background

and it will not key that hair

so what can we do well

you see how these edges are very anti ilias

meaning there's no transparency pixels

it's either green screen or black

so what I've Learned is you can

kind of use that and add holdout mat

and the key is

the hole that mat needs to also be anti aliast

so what you can do is just make a regular roto and

kind of a cool trick to make something just threshold

is if you plug it into a clamp

plug it into a clamp

and turn the maximum all the way down and check on

Max Clamp 2 or the bottom check Bam

so that'll get rid of any

transparency and just make it white

uh white and black

all an alternative is you can take a grade

turn the white point down to zero and click white clamp

that's another alternative you could do

but you'll need to set it to all

uh either one

I like the clamp cause I think it's pretty quick

so let me show you what happens if I don't clamp

this roto so I won't

I'll leave it with some transparency

and I will stencil that

so I just did a row around his hair

and I'll stencil that out

some kind of removing any remaining hair that's there

but because it

had transparency

it takes those transparent pixels

and starts eroding those in

so I'm introducing all these weird

kind of stuff going on

so really wants an anti alism

so if you add that clamp back on no problem

you look at

you look at the image and basically you've just

nudged the we've kind of custom eroded if you will

you can also use this roto shape to a road further

for example

if I put in a road here

and I start

eroding it like so so you rode down but it will

it will only erode where that

where that rotor shape is

which is another

another thing you could do

but it's kind of growing some of these hairs too

so I like to just stencil it out

and act like it's in a road

it's like a customer road that you've done

and from there you just do the regular stacked I think

and if you see when I remove the stencil

this is the difference that it made

so in one I have hair left over

and the other one

it is removed all the hair

and left only the green screen color

so this is a really powerful technique

that I suggest using when you have

that stuff that's left over

so let's take a look at the alpha also

so if I didn't

keep the hair

see all the detail that I'm gaining back

and in this scenario

you are around the hair

you are going to get a little bit of

basically right around this rotor shape

you're going to get some weird stuff

and that's because

because it has taken a

part of the green screen that was so far away from

where where needed to be taking

maybe there was a slight gradient in the green screen

it's going to introduce more differences

but they're so subtle

that it really shouldn't matter that much

it'll be much better than say this results over here

it'll still keep a lot more info

so don't fret too much about that

so to reiterate

adding a anti ilias rotor shape and stenciling it out

between your first IVK and the stack that you do

you basically have aided that first IBK

and then you start to rode out from that point

so sickest stencil and a rhodo there

and you can get rid of unwanted areas

okay so this last one is very

I would say

it's pretty difficult key because a lot's going on

one side is very blue

it's a gradient off into a very green color

and then there's all these little tracking markers

plus a bunch of shadows that you probably want to keep

so the first thing I noticed is when I plugged in an I

b k color and switched it to green

it ate away a lot of the green screen

and the reason for that is because it wasn't all even

and it was turning blue

since we're only using

this plate to grab an alpha channel at the very end

we can do really whatever we want to this plate

as long as it's giving us a good result

so what I've done is just graded this area with a ramp

back to a greenish color

so that the I became color wouldn't freak out

and it would give me a much better result

so this is working out

so let's start to mess with the dark

and kind of get into a groove with this

so a good a good

way working is just crank it until it explodes

and then just kind of work your way back until it

goes back to a place that's usable

okay so

seems like this doing pretty good

and you can just flip back

back and forth between the plate and

this first IBK color

to see where you're at with where it's about to erode

so now we can just quickly stack our IBK colors

start with 1

2

for yeah just exponentially

make it bigger

and again the reason why we stack them is that every

every time we make a new one

everything we've done before will not be

will not be affected

whereas if we plugged in

just a giant patch black at the very beginning

you can see the difference being

it is just kind of blurring

it's blurring and essentially ruining our clean plate

which we are trying to make perfect

or as good as we can get

so by stacking it

you're kind of doing it in layers

and going further and further in

now I'm pretty much good

so I'll just finish off that little area there

there you go

all through and IBK gizmo

and change to green this match

okay so this is pretty good

if I didn't want to keep the shadows

but let's say I wanted to keep the shadows

oh you know what I forgot to erase

but you can see

the power of the road too as I rode more and more in

it grabs a better pixel

to create now let's combine some techniques together

I'm looking at the first IBK

and let me just do my clamp trick so the bottom one

check on and then slide this one all the way down

and

hold the stencil

okay so now if we start making some shapes

I'm just gonna use an ellipse

let's look at the very bottom actually

so now I can start removing some of these shapes

and what you're essentially doing is

telling it to ignore all those and grab

a different area

so I can start getting some custom shapes in here

and so I'm removing the shadows

so that they're no longer in the clean plate

which means they're going to be picked up

when it keys

close that hole back up

okay so you also start to

see some interesting things when you start

eroding too much

such as all these all these artifacts and

all this nasty stuff that you'll have to to Kia so

I wanna show you the power of

how how far it's taking just a few pixels to aid

the clean plate process

so what you gonna do is

bring this over

you can start to key mix back in some areas

from the original plate and again you're gonna have to

clamp or threshold that rotor shape

but let's look at the bottom of our clean plate

and see what happens

when you bring in just a few pixels

like this area is a good example

see how different it is

what if we keep this area

zoom out

see how much that area changes when we

keep a little bit of it

every pixel is contributing a lot to the clean plate

and you're going to want to

try to keep as much as you can

and if you just flip back and forth between the plate

you can see the differences

so we can eliminate artifacts by just

bringing some of that stuff back

so

bring back some of these areas

you see the color is really being blood everywhere

this is a good example

so I'm done customizing my clean plate

and what I've done is

added little rotor shapes around

to help contribute original colors back in

if you see if I switch back on I'm

using more of the original plate to help

extend the edges

and that way I'm keeping all these colors

which are pretty um sporadic

and I get a lot of marks on the green screen

or I'm keeping it closer to the original plate

so I wanted to sable it it kind of goes haywire

and now I'm keeping more of what I want to be keeping

let me just demonstrate really fast what

a few pixels can really do when it's being extended

and why these I became colors are so Nicky

so if I just kept this little tiny area here

if I switch back it just blows up

and so then you probably get

some sort of harsh edge or harsh line

in this area or it might even look better

but you're seeing like a harsh line there

when I turn that back on

so you wanna watch out for stuff like that

see like that shadow

obviously it's pretty uniform here

but because the clean plate

now has a giant harsh line in it

and that was just from a couple pixels

see if I turn it off it's much smoother

but a couple pixels go a long way in this technique

because it's using

it to blur and basically generate a bunch of color

and blend with itself

so you wanna be very careful so

something like this

you don't have to go as

extreme of making all these little shapes

or you can make more defined shapes

I just started

basically adding a little bubbles of influence

if you want

you wouldn't want to really do this for

moving footage or footage that move too much

but you would maybe want to take some time to

write about the shadow or get a pretty customized

clean plate

that looked like the cast was completely removed

and that way your alpha will looked much better

and you'll get to keep things like shadows

and again this is a pretty extreme example

but let me just show you

what a regular IBK would look like

and what you could achieve

with customizing your clean plate to be as

effective as possible

here's the plate

here's a regular IBK and here's the

and here's the IBK stack technique

well thank you guys for watching

I hope this shed some light on how to

use IBUK here a little better

and what it's expecting when it's trying to

use the advocate color and how

how important it is not to change the

clean plate and try to get it as

as accurate as possibly for pulling the key

or else you get some strange artifacting

so this about wraps up my alpha section

if you have any questions about this technique or

anything I covered

please just let me know

and I'll elaborate on anything you want

um next I'm gonna be moving on to d spill

and I'm going to try to

not make it as big as a gap as my previous tutorial

um I'm gonna try to storm through it if I can um

getting through some Despil

which is which is really the good stuff so

I'll be starting on that soon

hopefully now you guys will know

what you're looking for when you're making your alpha

and how important transparency is

and how important it is to

to get your core mats and

how to combine those with key mixes and such

to get the exact help you need

and next we'll be talking about these pills

so I'll talk to you guys soon

and I hope you enjoyed