Although this course is specific about Krita, and not about how to paint in general, I will still need to explain some of the basic concepts about light and shadow in this lesson. This is because the concepts will correlate with the methods we'll be using in our next digital painting project. For this lesson, I provided a Krita file, so you can experiment right away with the concepts we will discuss in this lesson. The first thing we are going to discuss is the light direction. If we unhide this group layer and hide the rest of the group layers, we will see something like this. At a glance, what we see or how our brain perceives to be exact is that this large circle is a sphere.

And all of these smaller ones are holes at the surface of the big sphere. The question is, why do we think like that If we expand the group and hide this bottom layer, we can see that these small circles are no more than just a rotated version of the big circle. This is what's so unique about like direction. Most light sources are coming from top. Natural light sources, such as the sun or the moon are most of the time located above our head. manmade lights are also mostly located at the top area.

We usually place lamps at the ceilings and rarely we place them on the floor. Due to this habit, our brain are accustomed to see highlights at the top of objects and dark shadows at the bottom of them. Flipping these custom behavior on the objects inside our drawing will result in our brain to think that they are holes instead of 3d shapes. Knowing this concept is important Because when you create an illustration, our viewers will mostly expect to have the light sources at the top area. So is that means that we cannot add light sources from the bottom area. Of course not.

You can add light sources anywhere you like. It is just a good habit that if you add light sources other than the top area, you can help the viewers to understand that by drawing or showing those light sources. So again, to recap, light direction in shading is important as essentially it defines the depth direction of a surface. The second concept we're going to discuss is how color values define how we perceive depth. We can see this in the second group layer. This circle looks like a deeper hole than this one.

And this one looks like deeper than this one. While what I have actually done just differentiate the opacity of each of these circles layer. This one is set to 100%. This 160 percent and the last one has 20% opacity. The question is, why do our brain thing that darker color means deeper? Well, the answer is, in the real world.

When a light ray hits a surface, it will bounce off, it will keep bouncing off until it lost its energy. It is harder for a light ray to reach the end of a hole or the crevices as it will lose its energy before it gets there. That is why the deeper the hole, the darker it will get. Knowing this basic concept is important. So we can convey the depth of a surface appropriately to the viewers through the use of color level variations and other aspects. Have shadow is its smoothness or sharpness.

If we unhide this group and hide the other groups, we can see two bumps on this large sphere. The upper bomb is actually made from the lower bump, I just copy it and then at a blur effect to it. Notice how they both suggest different form. The upper one suggests that there is a lump in here with slopes around it, while the bottom one suggests that there is a high extrusion on the surface with steep chasm around it. So from this example, we can see the sharp shading or in other words, different contrasting color levels that collide each other without any gradation will suggest our brain to think that there is a steep depth changes in the surface, while smooth shading or gradient of different color levels will suggest our brain to think that there is a special mopping surface in that location. In this last examples, we can see that from the same circle shape by only leveraging the shading colors, we can convey a shape of humanoid face a shape of a cone and a shape of a coin like object.

So the conclusion of this lesson is that shading plays an important role to define the shape of objects inside the illustration. Essentially, we need to understand that when we do shading, we are actually many curating our viewers brains to think in certain ways. In the real world, the shape of objects will dictate how the shadows fall on those objects. In digital painting, however, we actually do the other way around. We orchestrate or design the shadow colors to dictate or to convey the shape of objects. So think of These three concepts that we have learned as our tools or our weapons to create different form of shapes inside an illustration.

First, use light direction to dictate the direction on the surface, whether it be inward or outward. Second, use darker shades to dictate the app. And third, use shading smoothness to show slopes and shading sharpness to show steep surfaces. I know that it is easier to say than done to apply them and to really master them. You will need a lot of practices especially if you are very new to digital painting or to painting in general