Okay, so this video is a direct continuation of my ambient light and ambient occlusion lesson

Мы видели, как огни окружения играют огромную роль в теневых значениях

We're about to go full speed ahead from there. So if you haven't seen it, check it out first

Let's recall our quick light ray diagram

We have the Sun a light ray comes from the sun hits the ground and bounces back up.

Oh yeah, and when these rays bounce they get progressively weaker. That information really helped us with our studies and breakdowns in lesson 1.

But now we want to add color to the mix. So we've got to do a bit more analysis.

Let's begin with the most fundamental aspect of how these reflected or bounced light rays interact with color.

So let's redo this diagram with this green card here. When a light ray

bounces off something, its color mixes with the color of that object!

Light rays inherit other colors throughout their lifespan. Now as for the exact balance of these interactions, don't worry

we'll get there. For now

let me just point out something obvious: the world contains a lot of different colored objects

So you can imagine there's a whole lot of opportunity for many subtle colors to bounce around.

Let's start with just the sun, and kind of simulate the lifespan of its light rays. And I want to remind you:

I'm only talking about color right now, not value. We'll bring value back into the conversation later.

So the sun's rays come in nice and orderly and uniformly yellow like this.

But when they bounce, the whole thing starts resembling the Wild West with colors coming and going from all angles and in all directions! And

that was just the first bounce.

These light rays will bounce again ... and again, and again - until they're simply too weak to be seen. And our little diagram here is becoming

pretty cluttered. Oh, and by the way, I haven't even put in the sky yet.

The sky is a giant dome throwing blue ambient light down into the scene.

Those light rays are weaker than the sun's,

but they bounce too, and when they do, their blue color mixes with the colors of other objects. Yeah,

I know, it's daunting. But don't despair, I have some good news!

You would literally have to be a computer program to keep track of all those light rays.

In fact, we do have computer programs that do that: they're called rendering engines.

I'll fire up a rendering engine in just a few minutes,

but first let's take quick step into the land of color theory ... because something very important is happening here that I need to point out.

So I've cropped in on our diagram.

What I'm going to do is start sampling colors from these bounce light rays and

painting them into this little panel that I've made down below here. Now. I'm only sampling the mixed colors.

I'm not sampling the direct sunlight rays or the direct sky light rays. Just the resulting mixtures that have occurred. In other words, our

simulated reflected light. And I say 'simulated' because the way light rays actually mix in real life is,

shall we say, more scientifically involved than this. But this approximation will still allow me to make some important observations.

Okay, the very first thing I want to point out, just aesthetically as I'm looking at all these ambient colors side by side, is that

there is a pleasing effect to them. They feel

harmonious. Or in other words,

they just look like they belong together. That they have something in common that binds them. Which totally makes sense, right?

They do have things in common!

For example, the environment they all came from. Also the sun and sky light rays they all came from.

It's almost as though the environment and the light source are the parents and these resulting colors are the children.

Let's bring in our color picker so we can examine these relationships under an artistic microscope.

So please watch this box as I start sampling colors. And I need to remind you:

I'm still only talking about color right now. Not values yet!

Okay ...

so I'll start here and I'll just scrub through again. Watch the color box as I do this.

Just kind of take general stock of what's happening. We'll go back to the beginning and just kind of run through this again.

Now I noticed two things happening here. The first is the colors the hues themselves were all over the map.

It was totally unpredictable where each color would end up. We found colors everywhere.

And the second thing I noticed has to do with the saturation. That is, the amount of color present.

The saturation level was generally within this range of the color picker.

So even though we were bouncing around like crazy finding different hues,

we were always within, you know, this kind of range in in here. And it's that aspect - this

saturation aspect - or actually I like to term it the other way: the amount of gray in a color,

that is a very important player in our ambient light discussion because grays link colors together!

You see, it doesn't matter where the hue is on the color wheel.

As we've just seen with our sample environment, the hue can come from anywhere but every hue or color you can think of has this

gray area in common!

And the closer they get to that gray the more naturally they can kind of weave, or

modulate in and out of each other. And that's exactly how we can take all these colors and

handle them without totally going insane! In fact, painting

the ambient light is often my favorite part of any painting! It can be fun and

expressive, so long as you have these principles in mind.

All right. Let's now bring value back into the conversation and do some painting.

You'll probably recall this sphere demo from lesson one. It dealt with both direct light from the sun and ambient light in the shadow.

We're gonna do something similar here today, only this time we can't use a blank background like that.

We need an environment to inform our color decisions. For the sake of demonstration, I'll use this photograph for my environment.

I'll just drag my color picker in there so you can follow along with my color choices and let's paint a sphere into this scene,

right on the path here. Now

I will choose to make this a white sphere because white has no local color of its own. In other words, you know,

its local color is perfectly desaturated and that's nice for our first demonstration

because it allows all the color that goes into the sphere to be the result of either the yellowish sunlight rays or the

ambient light colors that are bouncing around in shadow.

The first thing I'm gonna do is

establish a basic value block in to determine where the light and shadow families go. And of course

let's not forget about this cast shadow that positions the sphere on this path. And right away

I want to remind you that when you have direct light like the sun in this case, all those bounced light rays

we just looked at? We don't perceive those in the sunlight! Remember from lesson one that direct light visually overpowers ambient light.

So I'm just taking a light value, tinting it generically yellow, and that's really all I need to represent the sun.

Now the first thing I like to think about, especially when I'm painting an outdoors scene, is where is the skylight coming in from.

It's pretty obvious. It comes down from above. It's weaker than the sun, but still has some strength.

So this shadow is going to both lighten and get tinted blue in the areas that are exposed upwards towards the sky!

So when that sky light comes down, it's

gonna hit this area of the sphere and it's also gonna hit this area of the cast shadow.

The skylight will probably not get in here because it's way too deep of a crevice. If you remember lesson 1, that's where the ambient

occlusion goes. So for now, let's just start by applying the ambient light from the sky to our painting.

What I'm going to do is kind of pick a generic color for the sky. Now

this is probably going to be too light if I went super hard with the tablet ...

but because I'm using a tablet I can just press softly and

mix these colors on the canvas as if this were an oil or acrylic

painting. I can also sample, say, this color here ... mix it a little bit ... sample this color here ... mix it a little bit ...

So even at this early stage

I'm already starting to build up that intricate weaving of ambient light that is causing multiple shadow colors to occur.

And I'll just show you a little closer.

If I start sampling through these ambient light colors, you notice that we are starting to have those relationships

of grays! I've painted the most blue up here,

so the most saturation I'm getting is here.

Which is still very low and therefore remains bound to the other colors. And down here by comparison,

just based on the block-in I did, is warmer grays. But next to that blue, those grays that looked just dead before

actually have some meaning now because they're playing off each other! That blue gray against this yellowy orange gray. In my judgment,

there are two more areas to consider.

The first is: the sun would be shining down here and hitting the ground all in here and those light rays would bounce up,

giving a little more illumination to this area of shadow as well as more saturation.

And then lastly, of course, we'll have to deal with our area of ambient occlusion,

which will happen down here as we know from lesson 1. So I'm gonna tackle the reflected light coming up from this path.

But which color do I choose? Well, I know that the sun is generally this kind of yellowish orange color,

I also know that when it hits the path, it's going to lose a little bit of its strength.

It'll also lose a bit of its color as it inherits some of the path's color. And the path is kind of a neutral

earthy color, like a toned-down sienna color, maybe somewhere in this range.

So what I'll do, I'll just pick a color that's again fairly grayed off - so it remains linked to all the other colors -

maybe maybe a little darker. After all it is a shadow. We don't want to ever forget that!

It's a shadow. And I want to remind everyone: I'm not a scientist!

I don't I'm not trying to think of the exact scientific blending! I'm just trying to get some color in here

I'll adjust this as I go, I was trying to get some color in here that is

motivated by the environment! Now watch this I'm gonna switch to the smudge tool.

I really like the smudge tool because it does a great job with soft edges and when you're talking about

ambient light, soft edges are really appropriate because that ambient light is coming from everywhere. It's a soft effect in real life ...

so we use soft edges to help mimic that in our painting. Soft edges also help you to transition between multiple colors.

Now what I'm gonna do is just handle this transition area here. And I'm darkening this area a little bit,

starting to think about ambient occlusion.

I'm also using a slightly more reddish color just to continue on with these, like, sienna earthy colors of the path maybe bouncing into this

part of the sphere. I

might also want to try some greens! Like, maybe some of these greens from the environment

might be coming into our sphere just very subtly. After all those greens are pretty far away.

So they wouldn't dominate the reflected light.

But just a little bit of influence of them will help inform this passage of grays.

Another word for grays, by the way, is 'neutrals.' You might hear other people call them 'neutrals.'

And then, while I have this brush selected, I'll just, you know,

keep working the transition until there's a statement that I find interesting and aesthetically pleasing.

And I am pushing the colors a little bit just for demonstration purposes. And on that note,

I'm gonna push for a little more blue in the shadow.

Just cuz I'm looking at the shadows in the background and I'm seeing that there's a cyan quality to them.

Probably from the blue sky mixing with the green trees. But I don't have to repaint anything. Because I'm using grays,

I can really just paint over these colors that are there and they will mingle. So if there's one takeaway here,

it's that there is no one shadow color. There are multiple shadow colors across the same object!

Going to some warmer neutrals here for the ambient occlusion,

and again,

the reason I'm keeping it warmer is because there's not gonna be enough skylight colors here to cause any

blueish grays. Since the path's local color is warm, I'll just keep this warm. Don't worry,

we'll talk about local color more later on. And then as a last effort

I will grab an airbrush and set it to multiply mode.

I'll pick a warmish color like this to contrast from the blues and just start to address my ambient occlusion area.

Hopefully you remember from lesson one how soft ambient occlusion is.

Here's a photograph of a sphere that demonstrates this kind of softness that I'm talking about.

You can see that where the sphere meets the ground is more or less invisible to us.

It's lost.

And the reason it's lost, again, is because there are very few light rays to give us any information there.

So as painters we soften these edges to imitate that lack of information.