Illustrate Color & Light III: Direct & Reflected Light | Denis Zilber | Skillshare

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Illustrate Color & Light III: Direct & Reflected Light

teacher avatar Denis Zilber, Freelance Illustrator and Cartoon Artist

Watch this class and thousands more

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Taught by industry leaders & working professionals
Topics include illustration, design, photography, and more

Watch this class and thousands more

Get unlimited access to every class
Taught by industry leaders & working professionals
Topics include illustration, design, photography, and more

Lessons in This Class

    • 1.

      Introduction and the Class structure


    • 2.

      Principles of hard shadows casting.


    • 3.

      Spotlight and sunlight


    • 4.

      Adding sunlight to the scene


    • 5.

      Bouncing light and color changes


    • 6.

      Bouncing light rays all around


    • 7.

      Adding reflected light to the scene


    • 8.

      Understanding specular reflection


    • 9.

      Building reflective objects. Placing a highlight


    • 10.

      Adding metal surfaces to the scene


    • 11.

      Principles of light scattering


    • 12.

      Lighting a candle


    • 13.

      Adding smoke to the fire


    • 14.

      Things to pay attention to


    • 15.

      More Creative Classes on Skillshare


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About This Class

Welcome to Direct & Reflected Light, the third class in this three-part series, Understanding Color & Light. This third class covers the concepts and physics of direct and reflected light as they impact illustration and objects you want to capture in your work.

The skills in this class will allow you to render light from your imagination and capture realism. Once you've explored, understood, practiced, and applied these skills, you will have a huge advantage over those who depend exclusively on photo references. 

Whether you're looking to expand your existing work in digital illustration, or you've never considered Photoshop for illustration and are just feeling inspired, this series is perfect for taking your work to that next level.

Throughout this three-part series, we'll cover everything you need to know to add value, color, and light to your scenes & cartoon character designs using Photoshop. By the end, you'll feel not only comfortable with Photoshop's techniques and tools, but also excited by their many possibilities. We will start with a simple monochrome scene, using just one simple light source. As we move forward, we'll add different light sources, colors, and materials. Our final scene will include various materials that each reflect light, color & depth differently.

Also see: Understanding Color & Light I: Ambient Light & Understanding Color & Light II: Color 

What You'll Learn

In this class, you'll learn how objects and light sources work with direct & relfected light, and learn how to understand the intensity of light source and its effect on color.

  • Direct lighting. How does direct lighting affect objects in your drawing?
  • Light sources. How can you use color in rendering?
  • Exposure. How do different exposures change lighting in the scene?
  • Reflected and scattered light. How can you color light sources, and how do they work with your illustration?
  • Adding objects. How can you add objects and then determine shadows and lighting around them?
  • Finalizing your illustration. How can you provide polish to your final image?

What You'll Do

Deliverable. You will customize a simple, digitally illustrated scene or character with a light source, capturing direct and reflected light.

Description. You will build on your project from the other classes, adding light that brings depth and value to your work.

Specs. By the end of this third and final class, you'll have a finished scene as well as a solid understanding of the power of light in digital illustrations.

Meet Your Teacher

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Denis Zilber

Freelance Illustrator and Cartoon Artist


Denis is a freelance Illustrator and cartoonist working out of Tel Aviv, Israel. He specializes in exaggerated, cartooned features and characters. . . and he creates them from start to finish in Adobe Photoshop.

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Level: Intermediate

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1. Introduction and the Class structure: Hello guys, my name is Denis Zilber, and welcome to understanding color and light. Class three, which will be focused on direct and reflected light. We will be creating BC image in this class. Few works on this class structure. This class as well as two previous classes will be divided into few subjects. Each subject will we divide it into three lessons. First lesson would be the lesson on theory, second one will be an example of this theory, and the third one will be the class project. Basically, this image of this structure that we are rendering along the series. So, the subjects that we will be dealing with in this class would be direct light, reflected light, reflected surfaces, and light scattering. That is more or less it. So, let's start with our first subject, direct light. 2. Principles of hard shadows casting.: Okay. Let's start once again with the basics. We have only three possible light sources, three kinds of light sources that we can possibly encounter. First, is our well-known ambient light. We know quite a lot about it. We know how to build objects in ambient diffuse light. We know about all the stuff about light diffusion, and light absorption, and bent occlusion. Another light source that we can place into our scene is point light. Point light source is basically every artificial light source, any lamp of any kind, any bulb or anything that emits light and it's relatively small. Not like we learned in previous classes about the fire place, which also emits light. But due to its relatively large surface, it emits diffused light, the lights not concentrated in one point. So, this one is basically our major artificial light source. Any lamp of any kind would be a point light. Spotlights is very same principles has the very same effect. It gives very same effect but the only difference between point light and spotlight is, spotlight is more concentrated, and it produces more outcome than radial light rays. Of course, point light will cast really nice shadows, really hard edges. We won't be discussing in this lesson, in this class in general. We won't be discussing all the principles of building correct shadows because it's really complicated issue, and it needs a lot of knowledge of perspective and geometry and many different software. We don't have much time for this here. But, what is important for us is the principles of shadow casting and principles of combining different light sources in one scene. So, point light will create these radial light rays. Of course, the shadow that it will cast, the object that will cast shallow based on the point light source, will be more or less in shape of cone. Spotlight is the same. Sunlight. Sunlight is in fact, it is also a point light, but the sun is so big that we see all its rays as parallel. So, basically, the sunlight would create almost parallel light rays. It is kind of shadow we can draw, really easy to draw it. Okay, here is some little example of how to build the point light shadow. Here's our sphere that we discussed in previous lessons. Let's add some light to it. I placed some virtual spotlight somewhere here. So, it will be easy for us to to build it. Once again, we won't be dealing with exact and precise laws and principles of shadow casting because it is really a complex issue, and we don't have much time for it. But, the basics, I will show you. So here, we have our spotlight and it will basically build up like this. That is our basic sphere. On top of it, we are adding light diffusion. On top of it, we are adding light absorption [inaudible] We also add in some diffuse light from below, and we are adding some once again, ambient light from the [inaudible] Now, we will be adding light from more or less here, something like that. So, our light rays would be going like this. That would be our illuminated bar. Here, we will have our light cone, light spot. Here, we will have a little bit of diffused light that is coming from here, bouncing from here. That is more or less how it works. It's probably the most simple way to show the shadow casting on the sphere, on this simple set. But we don't meet here, as I said, before we meet here, all these exact and precise laws of shadow casting, what we need here is to understand how we build up light in our scene. As you can see, when I add a light cone, nothing changes here. Nothing. It happens because shadow is not casted as some dark color block on top of something, on top of the surface. Shadow is being casted as an exclusion from illuminated surface. So, basically, what we need to understand here is, when we create a scene with different light sources, we will be adding these lights one on top of the other. We also have to understand here that each light source, each light that will layer up in the scene will be adding more energy and more light intensity and more saturation to the scene. That is really important to understand. The more light sources you have, the more illuminated your scene is, the more saturated and more bright everything looks like. Let me give you few pre-rendered in 3D software examples. 3. Spotlight and sunlight: Remember this scene? Okay, let's add some light to it, some spotlight. Okay. Now, as you can see, the ambient light that existed here in the scene, the blue ambient light, is the light of the shadow here. What happens if we change the color of the main lights, not main light source but our spotlight? As you can see, the spotlight changed from white to yellow, but the shadow remains the same. Same with the red color. You see, the shadow remains the same. Why? As I previously told you, the color of the shadow is defined by your ambient light, so it doesn't matter what color of spotlight, or sunlight, or any other additional light source you will have in your scene, the shadow color would be defined always by your ambient light. Of course, your ambient light can be really complex with different light interactions, with different light sources, but your shadow light will be always defined by the ambient light in your scene. But all that light that's coming from different directions, and all the light that is being distorted by the air, and being reflected by different obstacles, and objects, and surfaces, and all that mix of different light interactions will define your ambient light, and that ambient light will define the color of your shadow in your scene. Here, same situation, green light, everything which is not shaded changes. Everything which is shaded, everything which is in the shadow remains the same, and it is the very same color here, here, here. You can easily see it. Okay, let's see another example. Let's change our light source. I'm talking about spotlight, light source intensity. Here we have like 50% intensity and we have this shadow. Here we have 100% in density and we have the same shadow. What we can see here changes only in intensity of the of illuminated surfaces, but all that remains in the shadow are basically the same, they remain the same. Here same color. It doesn't matter if it's blue, or green, or gray, or red, the shadow or the color of your shadow will always be defined by your ambient light in your scene. That is really important to understand because I see a lot of people that think that red objects will cast a red shadow, or blue objects will cast blue shadow, or many different theories and they are just not physically correct. It is not right. So you have to understand one simple rule, your shadow color will be always defined by your ambient light color. One more example, here is the same situation with the same light intensity, but here I'm changing the ambient light intensity. So, as we can see what changes here basically everything changes here, and why? Because as I said, every time you add an additional light source into your scene, these additional light will be edit up on top of the existing lighting condition. So here for example, we have really dim, really dark ambient light and all our shadows are really, really dark, almost black. Once we make this ambient light more intense, more bright, all the shadows are of course becoming more, and more bright, but also all the light spot because it's additional energies, it's additional light on top of the existing light, on top of the ambient light, it will be a bit brighter. Here, and here. Once again, if we add in some more light here to the ambient light, all the shadows will change of course. It will become more bright, and also the cone, the light spot will become more bright because the amount of light in the scene changed. That is one more thing that you need to understand. Each light will be adding up and I already told you, but it's really good thing to repeat a few times so you will understand it and you digest it really good. Each light source will add some energy at some intensity to your scene. So, you have your light intensity will be ambient light, which is as we said always exists in any scene that you're trying to paint. Each additional light source will add some intensity, and brightness, and of course situation to all the objects in the scene. But we can see it really good here on this red, it becomes a bit darker each time we we change this red, and this becomes darker and here once more. Once again, it happens because the amount of light in the scene is being reduced, not by the spotlight, but by ambient light. Okay, these are the main principles, and let see how we implement them into our class project 4. Adding sunlight to the scene: Okay. Now, here's our scene from our class project from the previous lessons, and that is the point when we actually left it when we stopped. Now, we are going to add some sunlight to this scene. Okay, I had to make here a decision where my Sun related to the main object. So, I decided that this would be our light direction, and this would be our light angle. More or less 60 degrees. So, what I'm going to do right now, I'm going to turn on all the hidden layers with all the illuminated areas, and I'm going to show you how this is going to look and explain to you why. Okay. Now, I have to tell you that this is not the complete and this is not the perfect solution for this lighting situation because we don't have here any bouncing light areas. We don't have any additional light interactions in the end. We don't take in account all the diffuse light around the colonnade. But, that is more or less correct in terms of basic lighting. We will be adding more light later. Right now, that is the situation that will do the job. So, as you see, I'm basically adding on top of each layer and each object, I'm just adding additional light illuminated area. That is exactly what is happening in real life. So, you have your object, and you have one layer of lighting, ambient light, and we have all the lights that is- you're just adding them up on top of the existing light, existing illumination. By the way, during your working process you can easily adjust the lighting here, and you can even switch the color. For example, you can make this lighting, I don't know, maybe green. This. Okay. Oh, this. Oh, sorry. It obviously need some adjustments here and there, but that is basically the whole idea, that you are layering up your light interactions, your illumination, and that is how it is in nature. So, that is the basic principle of direct lighting. So, we are not as- I had to repeat myself once again. I simplified for you all these shadow bidding process, because it is really and seriously complicated stuff. So, we're not doing it right now, but you need to understand few things that all additional life will be on top of the previous slides, previous illuminations. By the way, one thing that I maybe missed in previous lessons, because of the ambient light which is equal for every object in your scene, because ambient light is a really mix of different lights of different sources of light and different bouncing light and reflected light. Basically every light interaction you have in your scene that will build up your ambient light. So, when you paint your theme, you need to understand that your ambient light will be more or less, it will be the same ambient light for every object in the scene. Therefore, all the darkest areas, all the deepest shadows in your scene, will be very same tint of your ambient light. For example right now, we don't have much over really deep shadows, but if we had, our really deep shadows would be the tint of these blue but much darker of course. It will be something like that, close to blacks, but there are different types of blacks. Of course, you can make these dark blue almost black but still not black, not entirely black, and you can make these kind of brown really dark color which is nothing, it is not completely dark, it's not completely black and still it has some tint. You just need to take an account that your deepest shadow will have the tint of your overall ambient light, and that is really important to understand because this tint will unify all of your liking in your scene loop. Maybe it's hard to understand right now. But as much as you work, as much as you try this, you'll understand that the equal and, what I want to say is, if you have your lighting built correctly, and all of your ambient light, and all of your light sources are arranged in accurate and in precise way, it will act as a glue for your composition, and your objects and your themes, and your values, and every scene in your painting won't fall apart. That is really important to understand, and one of the most important things here is that, once again, your deepest shadow will be always the tint of your ambient light. Okay, let's move to our next subject, to reflected light. 5. Bouncing light and color changes: Now, in order to understand how reflected light works, you need to know if you really basic and really simple rules. There are two kinds of reflection. First, would be the specular reflection, and the main law here would be, the angle of incidence equals angle of reflection and it will always be that way in every possible situation. So, specular reflection is more related to glossy and highly reflective surfaces like mirror, or some metals, or wet surfaces. But the main principle of angle of incidence equals angle of reflection, will remain the same. But we also know, from the previous lessons learned from the class one, that light is being diffused, then once it hits the surface, it is being diffused. It's okay. The rule remains the same, but say, we have a line that is being reflected from a rough surface, not highly reflective. It will be diffused of course, but the main vector of reflection still will follow the same rule, of angle of incidence equals angle of reflection. So, basically, each time you see or think of some light bouncing around you, see it will follow the law of reflection, and it is really important to remember and to understand. The second rule here, would be there as we know, basically once again from the class one, that each time your light ray hit the surface, some of its energy, some of the light will be absorbed by the surface. It will always be this way. Even with perfect mirrors, little percentage of your light will be absorbed. So, the second rule will be that, a reflected light will always be less intense, will have less energy, will be less intense, less saturated, and less strong than the initial light. The more times your light ray bounces from one surface to another, the more times it loses energy. So, it is really important to understand this simple rule because that will give you a right perspective on reflected light and on any possible lighting directions and you'll. Okay. These are tools. Let's see how they work. Now, we have a sphere, and we have direct light, sunlight, we spiral the rays. All the rays here, some of them will hit this sphere and illuminate it and some of them will hit the surface, and will bounce off the surface, and it remained the sphere from different angle. Not from the angle of the light source, but from below. Once again, it's all based on this law of angle of incidence equals angle of reflection, but due to light diffusion, we will have also some of the light ray, some of the photons will bounce in different directions, and even backwards. Not much, but some of them won't follow the rule of reflection. Once again, not all of them. Most of them will follow the rule, and the main vector of the light deflection will be according to the law of light reflection. So, what we will have here on this sphere, we'll have some additional light here on this side, and we will have also some additional light here on the side. Though much less intense than this one, because this is much closer to the sphere. This bouncing light is much clower. This light will be much more diffused, much more blurred, much weaker than this one. It will be here. Forgot this one. But once again, because of the light absorption, these two lights; this and this, won't be the same intensity as this one. They will be much less intense. So, we can easily reduce it to, not completely of course, but like to 60 percent. Once again, it's not a precise measure here. It's just so you could easily see the difference. Fifty percent and this one would be like, this one would be as strong or more intense than this one, but less intense than this one, because these are reflected rays, and this one is two. But they are much less intense, much less strong than the initial light, than this one for example. So, that will be our our lighting, our situation here. Okay. Let's see how it works with color. Okay. Let's say we have a yellow surface, yellow floor, and the red sphere, and we have these white light that illuminates the sphere. So, what happens here at the very same principle as in the previous example, but with color. What happens to this color that the white light, when it hits the yellow surface, it receives its color information. Basically is not to receives, there's no such thing as received any color information. But the yellow surface will reflect more of the yellow spectrum of the light. So, we will see it as yellow light, and this white light becomes yellow light when it jumps off the surface, and it illuminates red sphere with yellow light from below, here and here. Here, once again, it will be much less saturated and much less intense than here. But what we need to understand that as in previous lessons, one of the previous lessons with the light spectrum, what happens here that we have our red sphere, and yellow light. That means that the spot here would be red with addition of some intensity, saturation, and shift towards the yellow part of the spectrum. So, let's say we have here, the dark red color. So, we will have something like more intense, more saturated and more orange. Something between the red and the yellow. Like this one that what we will have here. Here, the same situation, but the light will be much more diffused, and much less saturated. So, we will have the very same, maybe the very same color in the very same orange, but but definitely less saturated here once again. That is what is going to happen. Okay, let's say we switch the colors, and nothing will change in terms of principles, it just only the colors. Let's make this sphere. Let's make it blue. Okay, let's make it. So, the yellow and this one, we'll make red, the floor. So, what will happen here is, we have a blue sphere and we have white light. You know what, we can make it more, even more complex. Let's make the white, the light let's make it yellow. So, if we have a blue sphere and the yellow light. So, we will have the same here, the eliminated part of the sphere will be the blue plus yellow additional light, and that means that everything shifts towards the greens and there will be more intense and more saturated. We will have something like this or this. Okay, yeah. Of course, there will be some effect and pretty much significant effect on the surface, but on the floor, but we won't deal with it right now. So, the red, the yellow light which bounces on the red surface will have the same principle, the yellow plus red will give us orange and that will, that is the spot that will be on this sphere. Of course, it won't be exactly the same. The initial orange, it will be a mix between the orange and this and this green, and this blue green color. So, we will have something like this one plus, no maybe this. Once again, this more saturated, a bit more saturated, more orange. Okay, more or less in here and the very same here. That was a bit, will be much less saturated and this one. Okay, here, like this. No, maybe we'll need to make them less, but over here, the orange will be reflected, light will be mixed with this blue not with this one, with this blue. So, here we will have the blue plus the orange and it will give us something like, will give us this color at more cold. So, we will take it and make it more green. Okay, so that is more or less what we will have here, and this will work in almost, not in almost. This simple principle of layering additional light interaction, like additional illumination will work in every possible situation. Of course, I have to say here that, all these calculations are really approximate because, we don't know, in each situation you will have different intensity of the light, of your light source. For example, this green can be, you can easily have a really, really strong light source of yellow light, and you can easily have this situation now, or it can be, on the contrary much, much less saturated, much, much, much less intense, so you almost won't have the reflected light here. Because the reflected light will be the, your reflected light will be much less intense than the initial light. So, if your initial light source is weak, so your reflected light maybe won't exist at all, maybe you won't it see at all. The more the intense your initial light source, your direct light source, the more intense you will have of the light interaction and bounced lights, and reflected light. So, this for example, in this case, you will have this color much more saturated and much more bright for example. Yeah, and this one, sorry. This one is, will be a little bit low a lot, much more straight. So, you need it to the to take in account all of your light conditions, or your lighting basically indoor, in seeing an intensity of each of your light sources, whether it's ambient light or direct light sunlight, whatever, doesn't matter. You will need to build your reflected lights, bouncy light based on your, on this data, on this information of this initial, your initials light-seconds. Let's see a couple of more examples with and that they're rendered in 3D package. 6. Bouncing light rays all around: Now, that is our scene from the previous lessons,and we can clearly see that we have some light spot, which is not 100 percent white, it has some yellow tint. This is our blue surface, and this is our more greenish, white spots. So, it's kind of white with yellow tint. But it's pretty weak so, we almost have no bouncing light here. We have almost no effect on the sphere and they told us we have almost no reflected light, but the moment we make this light more intense. There can be the reflected light here and here and then here. The diffused light from the light rays that are being diffused from here, and once again this is our red, and this is our more warm in terms of spectrum, more warm, more orange-red because of the reflected light. Here, the same situation, will have the highly saturated this area and this will be basically the same color but much less saturated, by the way the same is here, you will have the red really intense really straight it really bright red, and here it will be much less intense. Once again because of the loss of energy because of the light being absorbed by the surface, by the floor, and the third situation is basically one something between this and this. When you have kind of if this will be our 100% of white this would be 30%, this would be like 50% or 60%, and you see, by the way you can easily see that these bouncing light almost have no effect on the shadow. Here no, even here no. Sometimes when you have your alight really really strong, really really intense, some of the light will bounce off the object. So, there will be few bounces, few interactions. Your light will get to the surface, bounce off the surface to the object, and then we'll bounce from the object to the surface back, and will color, in this case, it will color the shadow with orange, orange-red and here will be more orange-yellow, but I guess this slide is not too intense or maybe the angle of view is not correct. I guess if we would be looking at this scene from there, from this direction, will be seeing more of the bouncing light in the shadow. Though the very same situation and everything else is more or less the same principle, the less intense or the more intense your direct light is the more you will have bounced light and more you will have reflected light in your scene. Here's another example. Here what is changing is ambient light. The intensity of ambient light, and you can easily see that the changes of intensity of ambient light, almost have no effect on the reflected light here and here. Why? Once again, because it actually does, but it's really subtle really gentle effect of a density because as we know all the lights are kind of layering up, all the light interactions, all the lights including the ambient light will be summarized eventually into some color, and here the color we see is a sum of all light interactions in the scene. So, the minute we reduce the light intensity here in the ambient light, we will also reduce not too much, but in really gentle and subtle way. We will also use the intensity and saturation here, but for the most cases, your ambient light won't have much of effect on the reflected light. So, reflected light is in most cases, will be the effect of strong direct light like sunlight or light spots or some lantern or something. Not lantern, lantern is not good. Some flashlights for example. Flashlights and really intense and focused light sources will give you really good bouncing light and really good reflected light, and light interactions. So that is really to take in account because many people are being confused between direct light and diffuse light. Diffuse light, due to its nature of light being diffused in all possible directions gives us much less reflected light or much less reflected. All these colors both on the backside of the objects or shaded side of the objects. Once again because it being diffused into and distort in the air into different directions. Your main source of reflected light will always be the direct light or a spotlight or sunlight. That is the main principle that is the kind of application of our two basic rules. As you remember, we have two rules. One will be, angle of incidence equals angle of reflection, and the second rule is that the reflected light will be always less intense and less saturated than the initial light source. So let's see how we apply this, how we add some more light interaction, and more reflected light to our class project. 7. Adding reflected light to the scene: Okay. Now, what do we have here? That is our previous version of this scene and that is our new version. What happened here, basically the only thing that I did here, that I edit some additional light, and additional light interactions based on my current light situation, light setting. For example, that was our previous version and here I added some reflected light, reflected diffuse light from the carpet which paints colors this triangle with red, or for example these illuminated areas are the areas that are defined by the increase the amount of light in the whole scene. On top of your ambient lighting, when you add some additional light like this one or much more intense, and much more strong direct light source like sun, you'll have much more lighting in your scene and you will have much more diffuse light, and therefore here the previous version, and here we will have the light that will be diffused here and all these places in here. See, this was the previous version and this is what we have right now. In general, we have much more light in all shadows. Basically, all shadows are being illuminated from different directions. For example, here we have shadow that is illuminated by this pillar, these cone. It receives the light from the sun and diffuses it here into the shadow and on onto this surface for example or here this was the previous version and here we have much more light inside the shadow, inside the shaded area inside the shadows. We have much more light, diffuse light of course. Here for example, once again, we have the light, the sound light that is hitting here the floor and it will be probably diffused pretty significantly here and all over this surface. So, I added some diffuse light here and also here from the bounce light from here. So basically, as soon as you add another light source, basically the more light sources you're having a scene, the more light you will have, the more light diffused. Apart from direct light, and apart from hard shadows from the direct light, you will have also many different light interactions, diffused light interactions, reflected light all over your shadows. But, what is really important to remember here and to pay special attention to, is that as we know all these light interactions, all these diffused light spots will be by default much less saturated and much less intense than your initial and your main light source. Technically speaking, in terms of Photoshop for example here, I placed all these additional lights in separate layer below the main light because this vessel is much less important but also, so it won't interfere with the main light, so it will be on the background and also I can easily play around with it and make it less intense like this for example. It really depends on how much light do I want to see here in my scene, if I want to see a lot of light, a lot of illumination from all direction. So, I will probably make all of these both main illuminated areas and back lights, I will make them much more intense and much more accelerated. So, that is basically it on the reflected light. Once again, two main things, two main rules that you have to remember in order to master these base reflected light issue is, first rule is the angle of incidence equals angle of reflection, and the second rule would be the more your light bounces the more it loses energy and the less intense and the less saturated it will be at the very end. So and of course, the reflected light will be always with no exclusion. Will be always less saturated and less intense and less strong than your main light sources. So just remember this. Okay, let's switch to our next subject which is reflected surfaces. 8. Understanding specular reflection: Okay guys, let's now talk about reflective substances. As we already know, there are two kinds of reflections. The specular reflection and the diffuse reflection. Basically, we are now talking about the specular reflection. Specular reflection is the almost perfect reflection which means that all the light that is coming in going out according to the law of reflection without any diffusion. So basically, all those reflective surfaces like metals or mirrors or glossy plastics or even just wet surfaces will be reflecting light almost perfectly. Of course, there is some difference between the reflective attributes. But, they all will reflect the specular reflection making specular weight the light. But of course a mirror would reflect light in much more perfect way than for example glossy plastic. So let's see how it happens. Let's see the basics of these kind of reflection. Say we have a sphere which is illuminated by some point light. This sphere is let's assume it's highly reflective like plastic for example. Glossy one. So, the main difference between metal surfaces and reflective surfaces and glossy surfaces is that glossy surfaces are reflecting surfaces have highlights. Highlights is basically a straight reflection of the light source into the eye. So, on metal surface you won't see it. On glossy surfaces and especially mirrors and metals you will definitely see a lot of highlights. Besides that on metal surfaces you will see also the reflections on metals and mirrors. You'll see also reflections of all the surrounding objects in the scene. But, let's talk about highlights just a bit. So, we have our sphere which is illuminated by one point light source. And we have three different observers, three viewers that look at the sphere from different directions, and each one of them will see a reflection from this light source in different place. Regardless of the placement of the illuminated and shaded area, regardless of placement of the sphere related to the light source, they will see the highlight in different spots each one of them. So, basically the position of the highlight would be always relative to the position of the viewer. So the more the viewer is closer to the light source, the more the highlight would be closer to the center of the object here and the other way around. If your viewer is almost behind the object he will see the highlight almost on the edge of the object. That is the main principle. So, when you are trying to imagine and then paint something, that is reflective that has some highly reflective attributes. If this surface gets some reflective attributes you will need to first of all imagine and understand it in three dimensions and then you will build all the reflections according to the viewer position and the light source position. Basically light sources is important only for the highlights. So, if you have for example the crystal ball and a clear mirror ball for example, you'll need one besides the highlight from the light spot, you'll need also to imagine and build correctly all the surrounding objects which are being reflected in this mirror ball. That is the main principle. Let's actually build a mirror ball. Let's see how it works. 9. Building reflective objects. Placing a highlight: Okay. This is our non-reflective sphere maps here. In order to make it a reflective, we will need to do few things. First of all, we will need to understand where is our light source, where is our lights spot for example, where is it placed, and find the place for a highlight. Second, we will need to get rid of all this light diffusion here and all of these lines diffusion here because the reflective surface won't diffuse the light this way, it will reflect almost perfectly all the surrounding areas. So, it will reflect all the dark, let's put this way sky, all these dark grey sky and it will also reflect the edge on this spot of light, and then this shadow it will also reflect. So, we will need to rebuild this sphere according to all these reflections and of course according to it's position and the angle at which we are looking at the scene. Here I prepare this sphere so, I'll explain to you how it works. That is our basic here. We need here a reflection of the sky, and then we need here the reflection of the edge of this light spot. Yes, here. I'm not sure that it's 100 percent accurate, but for the sake of demonstration of the principal, I think it will do. I guess it's kind of record. So, this is the reflection of the all this big white spot, but we also need the reflection of this shadow and here it is. We will also need the reflection of the sky, so I added some here. You can with color picker, just assemble the color here and bring here. We will also need the highlight. So the highlight is once again according to the law of reflection, angle of incidence equals the angle of reflection, if this is our imaginary spotlight, so the placement of the highlight will be on this line somewhere here, and more or less here. I also added some glow to it so it will look more and more bright, and a bit more. I can also add some kind of darkening towards edges of the sphere, sometimes it really depends on the material this sphere is made of. Sometimes like chrome surfaces or really higher reflective surfaces will have these darkening towards edges on the. Now these don't look natural but this definitely will. So, let's say we add some object just to show the reflection of the surrounding objects. Let's add some object, some kind of wall, something here and the shadow rate, and we also need to edit here, and we'll look more or less, I would say kind of 80 percent, 90 percent like this. So, this sphere will reflect everything around it. For example, if I would place here some little ball just to give you additional example, it will be reflected somewhere here. You know what, I don't do it properly. We have a nice blake. Will be like this, and it will have a highlight like here. Then we'll also have some shadow. It doesn't matter. So we will have this sphere reflected somewhere here. On our main sphere will be like with reflection of course. The funny part here is that we will see the highlight in a different place because it will reflect the light from here and from here. So we will basically be seeing this highlight here, something like that. That is more or less the main idea of the whole thing. So reflective surfaces are always tricky to reflect. The surfaces, they're not simple. I would really avoid getting into mirror balls and all these reflections, because it's really hard to build the correct reflection. But you need to understand the main principle of the reflection, and reflecting surfaces because you will encounter them a lot in this and other more reflective or less reflective, even just glossy surfaces. You need to know where to place your highlight. So, let's switch to our class project and let's build some reflective surfaces there. Let's add some metal to the scene. 10. Adding metal surfaces to the scene: So, what happens here, I just took our class project scene and I replaced the two front pillars, instead of marble or instead of some kind of stone, I just gave them a golden touch. I also added some glow on top of it. Basically, here, you can see all those principles we were talking about. You can easily see here the shadow of the pillar and it's also been reflected here on the pillar itself. You can see the reflection highlight from the fire. You can see the highlight from the main light source from the sun, and here you can see the same, the highlights from the sun and the highlight from the fire. Here, I can see these place is being reflected here, and more cold, more green, this reflection will basically reflect the surrounding area which is blue, the ambient light. So, and here the same, same situation here. So, basically- also this decoration which has also a reflection of the carpet here an orange spot and it also reflects a little bit small. So, we cannot zoom in too much, but we can easily see the reflection of the pillars here. So, basically when you place some highly reflective object into your scene, you will need to take into account all of the surrounding objects. All the light sources and basically everything you have in your scene you'll have to reflect it in your glossy metal reflective mirror object. Here for example, just to show you the main principle, here for example these two pillars are golden. So, they obviously add some yellow tint to every surrounding objects that they reflect. For example, instead of showing us the blue color of the of the sky and the ambient light. It reflects it as green because of the yellow tint, yellow addition of the kind of filter of this material, but say I wanted to make one of the pillars made of iron or steel, without any tint. So, would get something like this. That will be different again I can play around with it, add some more reflections but the main idea here would be that, the glow that it will reflect everything as is. For example, it will reflect the blue sky as blue or you know some blue here. Blue sky as blue and the orange or yellow warm color of the fire it will reflect as warm and not as blue of course yes. So, all these starting from here which we cannot see the reflection of the carpet here, but if we could we would definitely see it as some red thing. It's not correct right now, but we will definitely see it as without any changes. That's what I wanted to say. So, but because of the fact that we are using here the colored metal gold. So, everything receives yellow tint. Okay, that is more or less it for the a reflective surfaces subject. Just remember to take an account everything that surround your reflective object and to paint it accordingly based on the law of reflection. Which is angle of incidence equals angle of reflection, and let's switch to our final subject, which is light scattering. 11. Principles of light scattering: Okay. Light scattering, really, really short, and really fun part. Say, we have a candle. A candle is obviously a light source. Burning candle is obviously a light source, and it emits light in different directions. But also, because of the fact that candle is made of semi-transparent material, part of the light enters the body of the candle, like this. The light is trapped inside, and it bounces there from one molecule to another until it fades completely. It really depends on the intensity of the main light that sends all these photons inside of the semi-transparent body. The effect can be really, really significant. The candle itself, besides the light, besides the flame on top of it, may become a light source because of all these light that is trapped inside of it. This event is correct for all semi-transparent materials like for example, human skin, or wax, or smoke, or something that is not on the right hand, it's not transparent, but on the other hand, it is allowing light to get into it and to bounce within. So, let's see how it works with candle. We will build a candle. 12. Lighting a candle: Okay, now, lets see how these light scattering works. Say, we have a candle, and it's regular candle standing on some mat surface, and also it has obviously, some ambient occlusion. The surface has its share of ambient occlusion, and the candle also has some flame and a glow on top of the flame. This part would be definitely more bright, almost like this, so we will make it brighter. We also will have an illuminated area. This is an ambient light, so it produces soft shadows as we know from the Class one. Okay, what happens with our candle here? Right now, it's really opaque. It's not transparent, so light doesn't enter it. So, we will need to add some light. We'll take it here and we soft airbrush, just add some light. See, immediately we start seeing that this candle is made of wax, and it is semi-transparent. It looks like semi-transparent. But what happens if we increase the intensity of this light? Right, say, okay. This candle wick would be much brighter, almost, know what, I will make it white, almost white. This light scattered inside of the candle. We can make it so strong that the candle itself, the body of the candle, will become the light source. So, this and that occlusion will no longer exist. Instead, we'll have some diffuse light emitted by the candle. What is really important to remember here that our candle is here for base light, for this part of the illumination. Our candle is the main light source. We also know that reflected light cannot be more intense than the light source, so we will need to adjust this part, this light to make it darker than this. On the other hand, if our light is so strong, our flame here is so strong and blinding, so we have our candle all white and this part will be all white. We can easily make this light here much, much more bright. Also, this light, this illuminated area will be much bright, of course, because of the increased intensity on the flame. In fact, I think that this part would just fill all this gap, and we will have something like this. But it's really extreme situation. Really, I don't think that you will ever see a candle bright, so much bright. So, basically, in most cases, you will see something like this. This will be something like this. That is how light scattering works. Basically, the more intense, the more powerful your light source, which is somehow attached to your semi-transparent object, the more light enters, the more light will be trapped within the object. If the light is strong enough, your semi-transparent object can easily become a light source by itself as this candlestick. Okay, and so let's go to our final assignment for our class project, and let's add some smoke outer to our fire. 13. Adding smoke to the fire: Okay. This is our scene and the outer fire. We need to add some smoke to it in order to show light scattering inside of the smoke. So, here's our smoke. Definitely, there are many different kinds of smoke. Some can be black, it can be colored, or it can be white. Let's try with black one and then we will add some. We'll make it white and see what the difference between them. Well, first of all, we need to understand that smoke as any object in the universe if it's not 100 percent transparent, it will cast shadows. So, smoke will cast shadows as well. So, let's turn on this here. Sorry, here. The shadow, here. Though the shadow might be really weak and transparent because of the light which goes through the smoke. Here, we will change it to this. Here is the shadow of smoke here and here. The shadow is from this smoke. Okay. So, we also have to remember that smoke is also three-dimensional thing and it will be also eliminated as any other object with your light sources, any of them. So, in this case, for example, this smoke will have its elimination from here, and this part of the shadow from this of the [inaudible]. Here we basically start adding some light-scattering like this, for example. We can play around with it and we can add it, we can make it more intense or less intense but the main idea is that the light will be fading slowly within the smoke, within its own body. So, we will make it like this, for example, and the needed illuminated side of this. By the way, here we have some really nice emanated by the fire itself, and they will also probably affect the the smoke with this color here format. Not necessarily but it is possible if you want more and more realism to your painting, you need to take in account every possible lighting directions. Here will make it more a bit more bright. You can also make this smoke much, much more transparent with simple overlay like this. Also, you can make it almost white. So, for example, if I take this and white like this. Here, how this smoke would look like with the- if it's white. I make it more, yeah. So, basically your light here, scattered light, is going up with the smoke. As the very simple principle as with the candle, it is being scattered within the body of the semi-transparent object, in this case, the smoke, and it's fading out slowly relative to the intensity of the light source and relative to the distance from the light source. Okay, that is more or less- let's make it more bright. A bit more bright, let's take this bright, right? Come up edit it here. Okay, I think we are finished here and that was our last subject for this series of classes. In a minute I will talk to you about, in conclusion, I will talk about the things to pay attention to and what you should take from this class and from the series. I hope you enjoyed the class and the whole series, and we'll talk in a minute. 14. Things to pay attention to: Okay, guys. In conclusion, few words and a few things to pay attention to, and few things to keep in mind. First of all, all these classes, all these knowledge is pretty much useless without you using it in practice and also without observation, without any observation skill on your side. So basically what you need to do right now, you need to look around your any point, any situation, you can look at any direction, and you will see all these principle that we were talking about. You will see them in practice. You will see them in the nature around you. So, but you need to learn to understand them, to see them and you need to understand them at that extend that you're able to reproduce them in your painting and your drawing. You basically need to look at some objects and understand everything. What happens was it, in terms of light, and then reflections, and then shadows, and refractions, and everything. So, you will need to do a lot of hand work here and a lot of hard work. Then, talking about not today's looking at someone, I don't know some door down the tree but I'm talking about years of practice and years of training your eye and your brain altogether. And that was the first thing I wanted to tell you and the second thing would be think of light as an energy. Energy in terms of a law of conservation of energy, which means that each time your light, you have your light source, analyze source, it doesn't matter which one, you have your light source and it's initial, your initial energy and your initial energy load for your light. So each time your light, your light ray bounces or just being reflected or refracted or absorbed, it loses energy. It loses energy. It can, according to law of conservation of energy, it cannot gain energy from emptiness, from the void, it can only lose energy. So that in practical sense it means that you will, your light will always be descending in terms of energy. It will always be losing energy and all your reflections will be each time weaker and weaker and weaker up until the point that your light is almost gone. So, it is really important to understand that light is energy and on the other hand, if you add some additional lights source into your scene, you will see that all of your light settings changed. You basically edit some energy on top of your existing energy loads and the other way around. So, if you turn off one of your light sources, will make the whole thing darker. So all of your light interactions, all of your bouncing lights, all of your reflections will be much much much weaker and together with the intensity of light and the overall light capacity, would put it this way, saturation of your colors will be changing also according to the light setting in your scene. So think of light as an energy and it will help you a lot. On the understanding that light is energy and the light each time you add some light source, you will be adding energy to your scene or if you reduce the, you remove some light source, you will be removing some energy from the scene and that will help you, I believe it will help you a lot with your work. So that's about it. I hope you guys enjoyed the class all the serious and I hope you learnt something. I hope you took something to your toolbox, to your workflow from these theories and have fun with absorbing painting and thinking about all the stuff. It's really interesting, it's really fascinating. It's kind of applied physics and it's really fun to, fun thing to do and to think about and to research. So have fun and good luck. Bye bye. 15. More Creative Classes on Skillshare: