Placeholder Image

字幕表 動画を再生する

  • 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

  • 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.

  • There's also one more aspect of shadow that I did not talk about in lesson one: the idea of a core shadow.

  • Can you see in this photograph how this area of shadow is a little bit darker than this area of shadow?

  • This is common with round objects.

  • But it doesn't happen always. It really depends on the exact nature of how the reflected light is reaching the object.

  • There might be in this case a little bit more of it down here.

  • This area is getting a lot of concentrated reflected light from the table.

  • This area is getting a little from the table as well as a little from the surrounding room,

  • whereas the core shadow that I outlined here is getting just a bit less reflected light.

  • So it registers as a bit darker. Remember that ambient light is weak,

  • so even minor changes in position can really affect how much ambient light an area is getting.

  • So there's a bit of that core shadow, and I'm just speeding through the rest of this process ... and here it is! Ambient light ...

  • ambient occlusion ... in color! Okay

  • folks! Now I want to take a step into the exciting world of 3d software!

  • I'll be using a piece of software called Blender. And Blender is free.

  • It comes with a real nice rendering engine, which I'll use to render variations on this simple scene.

  • I've got the scene set up right now with one sunlight and absolutely no environment.

  • So if I hit render we get a scene devoid of ambient light. Now I happen to have this nifty

  • panoramic environment photo. I'll feed that into blender and hit render again.

  • And would you look at that! Blender has calculated the ambient light!

  • I just went ahead and sampled those shadow colors, and we find that same transition of neutrals colors that are based on the environment

  • they live in. If I swapped out the environment to, say, this one ... and hit render on that ...

  • we would naturally get different shadow colors. And because I'm enjoying not having to do the work myself,

  • let's see what else Blender can do! Back in our original scene here,

  • let's bring in an additional object right up to our sphere. ...Did you see the change shadow colors?

  • Watch the bottom of that sphere.

  • When the ground goes down,

  • the sphere loses some of the green. And when the ground comes back up, the green is amplified on the underside of that sphere. We've

  • already seen the reason for this: rays from the sun inheriting that green and

  • bouncing up in a diffuse way into our sphere. And you notice the green is relegated to the bottom of the shadow,

  • closest to the green ground. The top of the shadow is still cast

  • blueish by the sky. The sky has a more direct route to that area,

  • so it has more of a say in the overall color cast. All right, just for comparison,

  • let's replace the green ground with a red ground.

  • And of course, it's the same principle only with red instead of green.

  • But I want to remind you: the color of the reflected light is usually a step down in

  • saturation from the local color of the object it's coming from. To demonstrate,

  • this is the red of the ground and this is the reddest part of the reflected light.

  • These are the subtle relationships we have to learn to see if we want our paintings to look natural!

  • All right. Are you ready for the next animation? Check this out.

  • First person to call out that sound effect gets a free video download from my store! Put your guesses in the comments!

  • Anyway, the reason I'm showing you this is because we have a new situation here. The entire sphere is in shadow

  • now. Which means the whole thing is lit by ambient light. In comparing them,

  • the color distribution is largely the same as before, but I see three major differences.

  • The first is happening in this bottom area. When the sphere is totally in shadow,

  • we no longer get that strong red reflected light. The reason is simple:

  • there's no longer any strong sunlight rays bouncing in that immediate area.

  • The second difference is happening at the top of the sphere.

  • I can see a little more influence of blue in the shadow there. Which makes a lot of sense because without the sunlight in play,

  • we can see more influence from the sky as it now dominates that top part of the sphere. And the

  • third difference I see is the area of ambient occlusion.

  • When the sphere is totally in shadow, it's getting less reflected light at the bottom,

  • so the transition to ambient occlusion happens over a larger area.

  • Back in Blender,

  • I'm gonna delete the sphere and add a different kind of sphere - one made of more obvious planes.

  • To recall one of my other YouTube videos, planes are nice because they have a very specific

  • orientation in space.

  • These planes help us more clearly see how different areas of shadow receive different sections of bounce light from the environment.

  • I really enjoy this little plane here. When we see it by itself like this

  • it just looks like a neutral pink. But in context, we know that it's one part skylight and one part red

  • reflected light from the ground.

  • Okay, let's go one step further and add local color to the mix!

  • I'll color the sphere yellow and the ground green. We have our render and I'd like to talk about this area first.

  • The color wheel shows us that yellow and green are next-door neighbors. And just like real next-door neighbors borrowing sugar from each other, the exchange

  • can happen very easily.

  • Just replace sugar with hue and saturation.

  • I can begin with the local color of the yellow