Light and Shadow for Beginners

Well, hi there students. Today we're going to do a brief demonstration on very basic lighting fundamentals. Now this lesson is going to be applicable to the 2D class, which is very basic, and what I'm going to do is teach you a formula that can help you know how to shade anything in the world. Now the second half of this video will also move a little more advanced for my more advanced students, where we'll cover bounced light. So 2D students, once you get to that point, go ahead and stop the vid, unless you really want to push yourself. So the formula is really simple. We're creating a magic trick on a 2D surface. We're trying to fool our viewer into thinking that they're looking at a three-dimensional object. Now to do that, we need to abide by a set of rules, and this rule is very simple. It means value change equals form change. Now what is value? Value is just a fancy word for darks and lights. So what does value change mean? That means that if you've got, say, a white area, like here, and it starts to change into a darker area, you've just had a value change. It's a transition from light to dark. Here's an image of a light ray, and where that light ray directly impacts on this sphere's surface, that's going to be the brightest point, the area that's perpendicular to it, kind of like hitting a wall. Now you notice, as the surface of that sphere curves, see how the dots get a little darker? See, that means not as much light is hitting that area. So as the form changes, see the values get darker. So value change equals form change. What types of values mean what? That's called a one, two, three read. A one, two, three read. Read means that your viewer's brain will understand that it looks like a 3D form, and for something to read, you want to have at least three values on your form. A light one, a middle one, and a dark one. So let's break down what the one is. And again, this is very basic. If you're an advanced artist, it gets a little deeper than this. Well, a one means that's where the light ray directly hits on a surface, just like you saw with that sphere earlier. We call that a highlight. So if you have a light source, and this is a picture of a cube from the side, and the light source is, you know, kind of up here to the right. If you drew a straight line from where that light source was, and see where it hits on that surface of the cube, that's where you get a direct impact, and it would bounce off. So that would be a one. So by looking at this cube, we can tell that the light source is above the cube, because the top of the cube is lit. So a two, that's a little bit different. A two is the middle value. We call that a mid-tone in art. Mid-tone is kind of the true gray, or the true color of something. So if you have a red apple lit under a spotlight, the things that would look red would be the mid-tone. A mid-tone means there's no direct light impact, and the area where the mid-tone is, that two, usually is the side that's running parallel with the light. We can see that the light is above, and slightly to the right. The side of the cube that we can't see, that would also be a one, but the light ray is running right parallel with the side of this cube, and so there's nothing directly bouncing off of it. So it's a middle two. So then there's a three, and a three is pretty simple. Basically, where there's no light, and it's on the opposite side of where the light's hitting. You got your one, you got your two, and it passes right by the side, but then here's your three on the other side of where the light is actually at. Now that's what's called a lighting strategy. If you want your thing to look really real, and look really good, shoot for three values at least. Now that's geometric forms, which are really easy to shade, but what do you do when you come into curved surfaces like this? Well then it gets a little bit more complicated. You still have a one, two, and a three, but how in the heck do you know where to put them? Well that comes through observation. Do you see there's a part here that where this red line is? Well if we look here at the outside edge of the sphere, and we've got light coming from this area, right about here is where the sphere curves away from where the light is. Well this red line is called a terminator. Terminator means anything past that point, no light's directly hitting it, so that's where you're going to get a pretty dark shadow. What angle is it at? Well if the light ray is coming this direction, your terminator is always going to be perpendicular to it. If our light source here is flat, then our terminator will be straight up and down. If we move our light source up and to the right a little bit, our terminator will still be perpendicular to it, but it'll be slanted somewhat. If we go even higher, it'll still stay perpendicular. All right, so let's do something really basic. Let's light this sphere directly from the side, but slightly in front. So first of all, here's the light ray coming directly from the left. So here is where it starts to curve away, and here on the bottom is where it starts to curve away as well. Let's start with that core shadow first. There we go. So do you see how it curves in a little bit, a little bit like that? That means that the light is slightly in front. Now if it were like flat, flat, that would mean that the light is directly to the side. Okay, so if we pull the light a little bit more towards the front, the core is still going to start here and here, but it's going to start to curve away a little bit more from us. Okay, so one fun thing to do is take your model and take a lamp and set your light up and then just walk around it and notice how the the core shadow changes where the terminator is at. Now let's put the light source behind the sphere and see what happens. All right, so you see how now it's the light is behind the sphere, but you see where the terminator is at? The core shadow is still starting at these points right here. So yeah, core shadow is tricky. You really got to kind of figure out where and how far out is this going to go, and you know, again, it's just observation. It's just kind of messing around and looking at life and seeing how it works. So now we pull the light source a little closer to us. All right, now here it is kind of slightly behind and to the side. Now it's like directly to the side and slightly in front. Now it's really in front. Now I'd say the light source is almost directly in front, and now all the way directly in front, and we can't see a core shadow. Now what I did was focus mainly on the threes there. I want you guys to see what happens when we add the ones in as well. So let's put a core shadow directly from the side, and now let's put the ones in. And so that's what the sphere would look like shaded directly from the side and slightly in front. Let's now rotate the light in front of the sphere but still flat and level the way it is right now. So I'm going to first push my core shadow out. It's still going to connect on those outside edges where the terminator is at. That's not going to change. Now let's grab the light, and because the light is in front, it's going to impact in this area right about here. So it ultimately doesn't matter at this point like what your angle is because watch this. The same thing applies if you're lighting it from the top or the bottom. We're just rotating the page. So having a good understanding of having your light perpendicular to your terminator will help you know exactly what that core shadow is going to look like. Now there's other times where your light's going to be behind your form. We call that being backlit. Notice how much of this is a core shadow and how now the bright spot, it is a crescent just like your core shadow used to be. All right, advanced method. Beginners, if you're watching this, you know you're welcome to, but this is going to be for students going into more advanced work. So taking that 1-2-3 read that we've just learned, we're going to level it up a little bit. This is what's called four-point lighting. So it still has what's called a 1-2-3 read. I call it four-point because we're paying close attention to a fourth element that's present in here, and actually a fifth as well. So we still have our highlight, we've got our mid-tone, and now we've got our core shadow. But there's two new things in this. This little light area here and this thing here. The light area is called reflective light or bounced light, and this thing right down here is what's called a cast shadow. What the cast shadow does is it grounds the form. It gives it a surface to rest on. What the bounce light does is it gives it even more 3D. It brings in light from around the environment, and it also helps separate the darkness of the cast shadow from the darkness of the core shadow here. Now bounce light applies to everything, even if it's in color. If you get that extra little bounce in there, it's going to look pretty awesome. So let's take a look at this strawberry. Here is the one, the light white and the pink. Here is the two, and that's all the red. Here's the three, and that's the core shadow, which shows that most of the light is coming from the top and slightly to the left. Now do you see this like grayish, whitish area right down here? That's called bounced light, and it gives it a nice little curve on the edge of the form here. It makes it really pop out, and that separates it from its cast shadow down here. What you want to do is you want to incorporate bounce light into as many different things as you can. See this guy's schnoz right here, this drawing of a nose? So we have a one, twos, and then here's a three, but you see how there's like a nice little light area right here that separates it from this dark cast shadow? That's bounced light. Here's an example of it using just basic geometric blobs. We've got our one, our two, here's our three, where it starts to curve under. Here's our cast shadow, and here is bounced light, which separates it, helps it really pop. So spheres and cubes and cylinders, you know, that's a great way to start, but if you really get into like these whole organic shapes like this, it really helps you practice the techniques. It's no different for complex shapes. This is still a sphere. This is still a sphere. It's just a sphere inside of a sphere. You're doing the exact same formula, just in a more complex way, and you can even go even crazier, like with this lobster, same exact process. Each little joint is its own form with a one, two, three, and then a bounce. So let's look at the formula for reflective light. What are the rules for this? How does it operate? It does three things. It separates dark from dark. So for this cube right here, on the three side, if there was a cast shadow down here on the ground, then this dark three side would start to blur together with the cast shadow, and our brain would not be able to separate the cube from the shadow. And so what bounce light does is it separates dark from dark. It also makes forms pop, and it happens mostly on the shadow side of forms. So on a cube, you would get a little bit of bounce down here on the three side, and maybe just a hint of it on the two as well. So on a sphere, remember you've got your one, two, three. Well, your bounce is going to happen again on the shadow side between the core shadow and the cast shadow. How big is it? Well, we'll get into that in a minute. How dark is it? It is lighter than your mid-tone, generally, and darker than your highlight. So think of your bounce as either a light gray to middle gray range next to that dark core shadow. So one thing to think about with bounce is that the closer to the edge of your form, the brighter the bounce is. You know, as we go into the form away from the edge, your bounce light starts to fade out. So what's actually happening here? Well, think of your sphere as a pin cushion with a bunch of pins popping out of it. What directions are those pins coming out from? So for example, if we did that here, we had a pin coming out from the side of the cube. Find where it would point out and come to physical contact with the ground, and that is where the bounce light would be grabbing the light from. Let's look over here from the side. Here's a sphere from the side. So what I want you to do is pay attention to this curve right here. Areas here are brighter. See how the form gets closer to the ground? That's where you're going to have the brightest bounce. And as you go up, up, up, up, up, it gets dimmer. Now, a cool thing about bounce when you're using color is that bounce light grabs the color of nearby surfaces. So see this sphere right here? If we put green next to it, it will grab the color green from this area. So if we have a pin cushion coming out, where is this grabbing it? Right about here. So we grab this color of green and then lower it down a step of intensity. So rather than having this exact color of green, take it down like by half in its strength, and then you paint it over the top there. It's boldest here and then fades out the further away we get. How do we know where to stop? Well, here's a really weird image of kind of like a pin cushiony sphere. The blue areas indicate where the bounce would be on this weird looking form. And all these little pokies are just, think of them as arrows. Where would they grab the light? And so say this little pokey bit would point here, and then right about here is where it would touch the ground if it were to continue to extend out. And that's where you would grab that color. Let's apply this to painting. So bounce light grabs light from other areas. So look at this heroic figure with a shield and there's lava down here. Well, the shield is pointing this way. So we grab the light from this area and paint it in. Do you see this purple glowy face right here? Well, you see here is the hand and here's the core shadow and here's the part of the hand that's facing that light source. It'll grab some of that light. So bounce light really helps forms pop and look realistic. So that was the tutorial on basic 1-2-3 lighting with a little bit of an advanced twist. Hope you guys find this helpful and I look forward to seeing you in class. Bye-bye.