Art Lesson: Light and Shadow

I've decided to make art lessons for a friend of mine and other people who are interested in learning art.

I've noticed there is a severe lack of fundamental lessons regarding art (or rather, drawing and painting, illustration, etc. that kinda stuff). Sure, step-by-step tutorials are dime a dozen but if you don't understand the fundamental basics, you might find it hard to apply it to your own personal work. A step-by-step guide on drawing an eye may teach you to draw an eye in that one position and look as seen in the tutorial but if you don't understand lighting and the underlying form and structure of an eye, then you might not be able to draw the same eye from other angles, let alone in conjunction with the rest of the face.

Bear in mind that I'll mostly deal with the technical aspects of art. There won't be philosophical lessons here such as the purpose of art, what is love (baby don't hurt me), etc. although I don't mind discussing them in the comments. Just keep in mind the function of this series is to teach the fundamentals of drawing and painting

So let's get to it.

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Light and shadow.

If there is one thing I may be able to impart you guys, just one lesson to give, it's this. You may disregard 90% of all the lessons I'll give save for this one and you'll still come out as competent (not great, mind you, but still enough to turn heads with your work).

This is the basics of how light and shadows fundamentally works. I'll probably be more in-depth in future lessons but for now, here is a starter. Like I mentioned earlier, this is (in my opinion, of course) the most important lesson in learning to draw so don't dismiss it despite being the basics.

For reference, we'll use a grey surface. On top of which, sits a grey ball with a specularity (I'll explain this, don't worry) similar to, say, a billiards ball. The lighting condition is just a single source, single direction, white light. Think of it as shining a flash light on the object. Basic stuff for now. We'll ignore color for now, that's a whole separate thing deserving of it's own separate lessons.

First, and probably the most important step, is we establish the light source with respect to the object. If you still can't visualize it mentally, from the viewer, you and me (baby ain't nothin' but mammals), the light source is to the right and above the surface. Pretty simple so far, right? Wrong! I can't emphasize how important this step is. If you don't get a solid feel for the light source early on, this will mess up your work, leading to lighting inconsistencies, which you definitely do no want. So please, take this seriously.

The initial value of the ball (and the surface) is called the local value. The local value is the inert value an object has if we take away any sort of lighting conditions. This is also key for establishing value ranges (a topic for another time).

Next step is to isolate surfaces in light to surfaces in shadow. Core shadow is when a surface turns away from the light source such that it no longer receives light from it. Cast shadow is what we are more familiar with when we think of 'shadow'. It is the shadow cast by an object unto another object/surface.

Again, seems pretty simple so far but this is one of those key-concepts-that-will-mess-up-your-work-if-you-don't-pay-attention-to-it kinda things.

Here's where it starts to get tricky. Despite what I said earlier about having one light source, light is a very fickle thing and it tends to bounce around everywhere, even from surfaces that are not as reflective as what everyone consider reflective surfaces, like a mirror. Here, we put in reflected light that is bouncing around the wall and table. When light bounces, it loses its intensity, making it weaker, which is also the reason you only observe reflected light on 'in-shadow' surfaces. 'In-light' surfaces simply have a too strong lighting on them to make bounce light have any noticeable
effect.

Reflected light (or bounce light, same thing) is also the reason why the cast shadow diffuses more, losing that crisp edge the further it gets from the object casting it. There's just more space for light to bounce around the farther away from the object than it is closer.

There really isn't much reflected light on the surfaces of the table and the ball that are close to one another, that's called occlusion. Basically, the space for light to bounce around is so small that it makes that general area really dark.

Now, we move on to the in-light surfaces. The basic gist of is, without specularity (which I'll cover in the next step), surfaces that are directly perpendicular to the light source receive more light (which also means they are lighter in color/value) than those that are not. Since our object is a ball, that means the surfaces curve away from the light source, giving it a gradation as it recedes towards shadow.

Specularity is the measure of how well an object reflects light. More commonly, it is referred to shininess or how shiny an object is. The most extreme cases high specularity would be mirrors and chrome while the opposite and of the spectrum would something like concrete. Commonly though, most specular objects are just specular enough to only reflect the brightest things in the area, which would usually be the light source.

The point on the object that recieves this reflection is called the specular highlight (or simply highlight). The angle of incidence of the reflection toward the viewers eye would depend on both the position of the light source and the viewer himself. As such, should we move our seat and observe the ball from another angle, the specular highlight would also change, while all the other characteristics covered previously would not. The exact placement of the specular highlight is pretty complicated (and I'm not sure I even completely get it myself honestly) but the basic gist is, think of the object (in this example, the ball) as a flat mirror. Now adjust that mirror's angle such that you can see the light source. The plane of that mirror would be parallel (or equal to) to the planes on the object that would recieve specular highlights. Note that it's not quite the same as the perpendicular plane as covered previously so do take care.

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So there you have it, the basics. Yes, I know, it can be a bit daunting. And yes, those are still scratching the surface but hey, art isn't easy. Back in the old days, painters would apprentice for years just learning this stuff. So don't be disheartened if you don't get it right away.

I'll cover more in future lessons should you guys be interested. If you find it useful and want more, I'd appreciate a like and a share. Also if you have questions on this topic, study materials, future lessons, etc. just comment below, and I'll try my best to answer.

Cheers, maties.

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if you need to contact me for whatever reason.