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This is going to be really cool! I've got this Compositing project open here
and I have another great somadjinn photo of this blue textured graffiti, phone
booth, looks all kind of cool and grungy and stuff. Then I have this great kind
of chubby white hairy hand of mine, just sticking out, trying to grab the phone
here. I am trying to composite these two elements together.
Now this is not any kind of believable composite whatsoever, there is obviously
a very strong blue tint on the background and my hand is obviously a flesh tone
colored hand. So we are going to use a great trick of Levels to actually
combine them. Now typically you think of Levels as a luminance adjusting
effect, but you could also correct and composite color with it as well.
I am going to select my hand layer, and I am going to double-click Levels to
apply it. Now, here is the trick, we could actually change the channel that we
are working on here in Levels. By default, we are working on the RGB Channel.
That's a composite view, basically, all the channels at once. But if we click
this drop-down, you see that we could actually work on just the Red Channel,
just the Green, just the Blue or just the Alpha Channel.
Now remember that, we are going to be coming back there in just a second. If I
come over here to the Composition panel, and I go down here to these three
little circles here, this is actually the channels that I am looking at. So if
I want to see just the Red Channel, I can go over here to this drop-down and
just click Red and all I am going to be looking at is the Red Channel.
Now here is the power of Levels here. If you are looking at the Red Channel
here in the Composition panel, and if you are adjusting the Red Channel in the
Levels effect, then you can bring these two together as far as their luminance
values go. Then once you do the same thing with the Green Channel and the Blue
Channel, then you will be amazed that magically you have a great composite.
Let's see how this works. I am going to turn on and off this effect
to refresh my histogram here and for the Red Channel I am going to bring the white
value in here. Essentially, what we are trying to do here is make each grayscale
channel. So basically, let's say, for example, we are looking at the Red
Channel, we want to make this a believable composite just for these grayscale
values. Now this is more of an art than a science,
but you want to look at these shadow areas and choose from the shadow areas, you
want your shadow areas basically to match those shadow areas. You want your highlights
to match these highlights. You want your overall contrast to match as
well. You probably could stand at a real bit more shadow to the hand here and
that looks okay. Oops! I actually just notice that I have been
working in RGB mode; you've got to be careful about that sometime. Sometimes
when the histogram needs to be refreshed and when you refresh it, it defaults
you back to the Composite view the RGB view. So I am actually going to go
back to my Red Channel and actually we do have some visual anomalies to fix here.
That looks pretty good, but the contrast might be a little bit strong, here
we go, I think that looks better. Now let's try the Green Channel. Now remember,
we're going to need to change it here in Levels and here in our Composition
Viewer and wow! There is a big difference there. See how bright overall the
background is here, and how dark our hand is. Just notice the side now, the
reason why it's so bright is because we are using RGB values. RGB are the color
components of light. So the more light there is, in other words,
the brighter these channels are, the more light of that color is being used
to make the composite. So the fact that the Red Channel was dark relatively and
the Green Channel is pretty bright means there is not that much red light being
used and there is quite a bit of green light being used.
As you can probably guess, because our image had a bluish tint to it, that once
we get to the Blue Channel, there is going to be quite a bit of blue as well.
So it is going to be bright like Green here. Now I am going to brighten this
up, move that to about there and actually the shadow values do need to be a
little bit darker here. Now we do want the brightest part of our hand here in
the Green Channel to be pushed to pure white, but that's not quite bright
enough for this instance. So what I am going to do is go over here to
Output White, and I could use this to adjust the white value. I am actually going
to push this to about 280 or so to brighten up a little bit more. I do like
the shadow areas, these shadow areas kind of match here. Overall, it's just
a little bit too dark, so I am going to take the gamma slider and adjust
that quite a bit and that looks pretty good. Now let's move along to the Blue Channel,
remember to change it in both places. Wow! Look at that contrast. As predicted,
the blue channel here is very bright, again because there is a lot of blue light
being used to make this scene. Brighten up our hand quite a bit by dragging
in this white point slider, also adjust the gamma quite a bit, that midtone
value, and I am actually going to blow it out quite a bit. This is a little
ridiculous looking and I realize therefore we are just making a composite of
this hand and this phone as is. This looks too grainy, but keep in mind that
we are only processing one channel right now. So if doesn't quite look perfect,
it's okay. I am also going to take Output White up quite a bit, maybe about that
much. Good! Now our hand looks pretty bright as does the rest of the background.
It looks a little bit over bleached, like the background. That's what
we want, we want to blend in. Now we have adjusted all three Channels, Red,
Green and Blue, let's now take this back to the Composite view and see our
end result. Hey, hey! Not too shabby, let's take a little peek at what we
had initially when we started. As I turn off Levels, that's what we had. We have
come quite a bit using this trick, adjusting each channel individually.
Now believe or care about these Levels, you can just stop watching the movie
right now, but I want to show you an extra little trick to make this composite,
a little bit more believable. As I zoom in here, I could see that there is a
little bit more noise in the photograph than in my hand photograph. Really hard
edges are usually a dead giveaway of a fake digital composite.
So what we want to do is, soften up these edges. So I am going to search for
fast blur and apply the Fast Blur effect to my hand here. I am going to add a
little bit of blur, just a little bit. I don't want a blurry hand like this, I
just want a very, very slight blur. Actually there is probably better ways to
do this, but I am just going to add Fast Blur for the sake of time and give it
a blurriness value of 1. You can hardly even tell I did anything until
I turn the effect off and on again. So you see when it's off, you see these
very hard edges here, kind of have a dead giveaway, if this is a composite,
but as I blur those edges, it makes a little bit more believable that this
hand is actually in that scene. So if close these up you could see the before
and the after, not too shabby. Now, our journey into the world of color adjusting
is not even close to being over yet. Let's take it up a notch by learning
another great luminance adjusting effect, Curves, coming up next.