After Effects CS6 Tutorial - 87 - Fixing Transparency in Alpha Mattes Video Lecture | Adobe After Effects CS6: Complete Course from Novice to Pro - IT & Software

hey everybody welcome to another After
Effects cs6 tutorial
I'm your host buddy Blackford and today
I want to show you how to clean up your
alpha so that you can use alpha mats
properly without having a bunch of
transparency in them so what I mean by
that is I'll show you on my comps here I
pretty much just took a some footage of
this ak-47 which I have to credit who I
got it from I got it from cute stock
footage calm and this one was free and
you can just download it and use it if
you want to follow along or you need
some free green screen footage so I have
this then I keyed out using a colour
keyer and After Effects that's native
and let me show you the Alpha of it
right here on this RGB thing we click on
that and it drops down and we go to
alpha and let me take off the background
and you can see that the Alpha isn't
totally black and white because when I
keyed it keyed out some of the color
values that were in the gun or left them
in there so it was either one or of the
two so now we've got an alpha that has
gray area in it so some of that will
probably be a little transparent and
I'll show you this when I go back to RGB
and if I set this to have the track map
for this you can look and if you look
closely you can see that it's
semi-transparent here and in other parts
of the gun and that's not that's not
what I wanted I wanted a full white
alpha that isn't messed up like I'll
show you again take that off and then
we'll move this one down turn this off
and this one has been corrected so that
it is fully white and does not have any
transparency in it so I'll show you how
to do that real quick let me turn all
this back on
I'll turn the blunt you went off and
I'll just uh I'll basically start from
scratch and we'll key something out real
quick and I'll show you how to do that
really quick without going in too much
in depth so let me take this track mat
off I'm gonna bring in my video footage
that I have which is this let's bring it
down and we've got this video footage of
this done kind of like moving around I'm
gonna put it we'll just keep that full
for now so on the video footage go to
effect keen key light and in cs6 it's
key light one point two we're gonna take
this screen color right here we're gonna
click on the dropper and then we're
gonna click close to the gun here and
it's going to take away pretty much
everything we've got a little bit going
on here we can increase this screen gain
maybe take away some of that edge
stinking adaptive resolutions going off
well crazy on me so we got not that way
making it to just just mess with these
values that's it's messing with the
background to which I didn't want so
we're not gonna mess with the screen
gain our screen balance we're gonna come
down here to screen Matt and we want
this clip black right here and we're
gonna increase that a little bit and
it's going to eat away at the edges so
we don't have to see that green on there
you don't want to go too far to eat away
like all the what's going on there so
that's pretty decent right now now if I
take a look at the Alpha by turning off
the background and coming to this and
looking at the Alpha we can see that
it's blotchy and that's not what we want
we want it to be full so I'm gonna show
you how to fix your alpha real quick go
to effect and then come in to color
correction and we'll go to levels and
let's go to levels individual controls
that's a we're gonna come down here to
alpha and we'll switch this to our alpha
again so we can look and we're going to
adjust these to make the alpha all white
so I think it's this alpha output white
and we're gonna increase that yep and
you can hold shift to make it go faster
we want to get it just so it it gets
everything so we still have some there
so it's keep on increasing
and that looks good now if we go back to
our RGB we look here and I don't see
much transparency by the way this isn't
it's not a perfect key here I mean you
can see some green around his his
fingers and around this right here but I
didn't want to go into full depth about
keying I just wanted to give you
something to work with if you want it to
follow all along so now we've got our
alpha that is fixed and solid now if I
put it over top of my background and
move it right above the background and
set to alpha matte we're gonna see that
it correctly works and has the element
in there so if I switch to inverted it's
going to take out everything and not
leave anything showing inside so that's
how you clean up your mats if you ever
need to having a great mat and trying to
use an alpha where that is gonna cause
transparency issues so you want your
alpha is usually black and white unless
you want to have transparency for
example if you're using smoke or
something like that and you have a
footage of smoke with an alpha channel
and you want it to kind of like blend in
nicely so that's just an example that's
all for fixing up your mats hope you
guys have a good day see you later