Name: Understanding Shadow Colors (Ambient Light Part 2)
Uploaded: 2018-08-31T04:39:30.000Z
Duration: 25 min 18 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

So it should come as no surprise that it also plays a huge role in shadow colors

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

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

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

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.

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

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

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!

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

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,

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.

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!

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 ...

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

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,

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