Lighting and shade is a tough subject to cover. There are so many things to consider, but we'll go over the basics and things will start to take shape eventually. This will be split into two parts. The next will be a separate post on its own.
I'll be here to try to answer as many questions you guys have, so leave a comment if you feel confused or unsure. Also feel free to comment on the lesson itself.
Although this is a weekly 'Thursday' lesson, i'll try to answer your questions well after this is over. Don't hesitate to leave a comment!
Okay, you've done a sketch, but it kinda looks a little flat. You want your drawing to look more realish. Thats where shading comes in. When you shade things, you're moving from the realm of the flat and shape, into the plane of volume and form. The first thing you should do is try to think differently - in terms of values and volume.
To clarify, what i mean by shape: Imagine taking a piece of paper and cutting it out in the shape of a mouse. Its flat. Formless. Wave it about and it'll flop around like a... piece of paper. Yep, we won't mistake that for an actual mouse... but it is still recognizable as a mouse because you have the boundaries of the mouse. By looking at its outer lining, or its sillhouette, you can call it a mouse.
Now, grab the mouse on your table. Grasp it and turn it around. You can feel the form of the mouse. It has volume that you can perceive. Its got different levels of light and dark on it. Despite the fact that you can't feel things in your drawing like you can in real life, this illusion - the illusion of form - is what we want to give to a painting.*
The first thing to understand about shading is the concept of value. When talking about shade, we will use the word 'value' a lot. What this means is basically the brightness or darkness of something. We will refer to this grayscale here to define value, because value is essentially the range of gray on your from white to black. Woah there, before you stuff that into your head, know that colour can have values too. To make things easier to understand, i'll hold back explaining colour values for now.
Even when we move on to colour, though, we don't forgo this grayscale completely! This value thing applies both in black and white as well as colour. Lots of digital artists check their values in grayscale, even though their drawings are in colour.
The magic of value is that when you add the different ranges of value to a painting, suddenly, poof! You have given the illusion of volume to an otherwise flat shape. This is pretty much what shading is all about. Adding form to a flat shape. Its important to use a wide enough range of grayscale values to add to the illusion of form.
When talking about value, we will refer to things as lights, halftone and shadow. This image here defines these different levels of lighting on a sphere. You don't have to memorize them, just know that they exist, and i'm not blabbering some art gibberish.
All objects can be broken down into basic shapes: Spheres, cylinders, cubes. Modifying, combining, slicing these basic shapes will get you more complex shapes. That's how ponies are made. In its simplest form, the pony is made out of combinations of cubes, spheres and cylinders. We base ponies off of these shapes, which we eventually refine until it looks more believably pony.
Light sources are pretty simple. Put your hand against the light and see which part of your hand is the brightest. It'll be the part that's facing the light.
Shadows form on the areas that are blocked from light. Look back at your hand, and you'll see the darkest bits are opposite the direction of where light is coming from.
In light of this, it is important to note where your light is coming from when shading a figure. Always keep your light source(s) in mind when you shade things.
The shadow shape of an object is the mass of shadow that starts where the light ends and the shadow starts. Basically, the shape of the shadow. We just use one tone of shade for these. This is the simplest form of shading, and is pretty much what cel shading is.
Cel shades on its own doesn't really give an accurate representation of form, though, and we'll see why in a bit. Even in realistic shading, we start off with shadow shapes first to simplify things, and then we move on to refining things from there.
Transitions of dark to light is important in defining form. How quick your shades transition determine how sharp or how round something is. Round objects like spheres, cylinders, have soft edges, and so transition is slow where there is roundness. Cubes and pyramids have sharply edges, and so transitions are quick where things are sharp and pointy.
Sharply fastly, slowy smoothy. Got it?
Keeping this in mind, lets look at some shaded shapes. In the following examples, we will use only ONE light source, and hence only one shadow shape will arise in these examples.
For simplicity's sake, these shapes will be shaded using directional lights (such as spotlights and lamps). These shapes will be approached differently under sunlight, or with softer lighting. Don't worry though! In grayscale, what changes with different types of light sources is how fast things transition.
Shading cubes is pretty straightforward. Depending on the direction of the light each plane will have different values. These flat planes will be equally lit throughout. Transitions between planes of shade are quick. (Sharply fastly)
As you can see here we need to approach cylinders differently than cubes. The top of the cylinder is a flat plane and we can evenly shade it like a cube.
The sides of the cylinder, however, are rounded, and so the shades transition differently. (Slowy smoothy) We add lots of middle values before going into the core shadow.
Take a look at where the shade stops changing and enters the core shadow. See that there is a sort-of-not-really line there? This is the terminator. As its name suggests, this is where the shade 'terminates' its value changing. Past this line, no value change occurs. Ah, yes, but hold it.
Look around at objects around you. Most of them have varied values past the terminator. What gives? Welp, the main culprit here is reflected light. Reflected light bounces off surfaces onto other surfaces, and things get brighter. More on that later.
The sphere is approached much like a cylinder, only instead of horizontal shades, we use more... spherical shapes of shades. Think of the difference between slicing a piece of bread and slicing an onion. The slices of bread will be even throughout, while the onion will start off big in the middle, and then start getting smaller.
Like a cylinder, most of your shade transitions occur before it hits the middle of the shape.
Cast shadows are the blobs of shadow that get left behind on a surface because the light can't get to it. Cast shadows make your objects feel 'grounded', when things are on the ground, and make it feel like they belong in the picture. Seeing an object on the ground without a shadow is like seeing a vampire without a reflection. Its off putting. You wonder if it'll come and take away your shadow in the night.
Now that we understand shades, we can move back to reflected light. If you look at your arms, you can see that the darkest spot is not at the very bottom edge of your arm. Its somewhere in the middle. What's up with that? The cylinders above aren't like that. Welp, this is reflected light's fault.
All objects (except maybe antimatter or black holes) reflect light. This is how we see things. When light reflects off things and bounce into our eyes, we see them.
Similarly, light will also bounce off objects onto other objects, making things lighter. Like so
Look ma, no cast shadows!
Note that your reflected light will never ever make your shades lighter than your lights. This is because all things will absorb some light before reflecting it.
Hence, your reflected light will not be as bright as your initial light.
Speaking of cast shadows, keep in mind that reflected light will be reflected yet again, only with less intensity. This will make the cast shadow near your object a little lighter than the ones directly underneath an object, where light can't get to. This lil pocket of little to no light is called an occlusion shadow. (ow. my brain hurts.)
To explain specular lights: Remember when I said light bounces off of stuff into your eyes and thats how you see? Well at a certain angle, there exists a point where the largest amount of light is reflected into your eye. This will create a specular light. This is what makes things look shiny. Although, note that for muddy things like cloth won't have nearly a bright a specular as, say, a metal bar. Reflectivity plays a big part giving the illusion of material.
If this is hard to understand, try to imagine holding a shiny metal ball. Try to angle it so you can see the sun reflected off the ball. (Tell your imaginary self not to stare.) That spot is the specular light.
This can be a point specular light, as shown above, or can be slightly more distributed along the form. It really depends on your light source.
Without the influence of lighting, a black shape be black and a white shape will be white.
On a bright sunny day, a black thing will still look black. Take a really close look at it though, and you'll see that its a lot lighter than black. Why does it still look black then? That's 'cause every other thing is bright as well.
Inversely, on a dark night indoors, the soft moonlight shining in through your window will make a white object look still pretty white, despite the fact that its values are, currently, a dark gray, as in this picture: night time
Take a look at these squares, specifically the ones in the middle of the squares. They look like they're different colours, right?That middle square is the exact same colour. That's relativity at work. In a dark environment, light things look light because everything else is bloody dark.
When trying to bring form into flat shapes, you should try to look at the planes of value in a form.
At first glance, trying to get all those levels of light will be somewhat intimidating. So many levels! Shapes? Edges? Reflected light? Specuwhatchamacallits? Sweet lincoln's mullet! Phew, okay. Gotta relax.
The good news is that you don't have to place every intricate level of value from the get go. The slightly worse news is that this step comes afterwards.
Approach shading simply and it will be easier to understand. Start off by defining your shadow shapes as I mentioned above. Your shade boundaries help simplify things. Now, try to write down in numbers where each level of light will be.
Take a look at that sphere lighting picture again, and you'll see what I mean by levels of shade.
This guide is an excellent start on how to go on doing this plane of light thing.
And then post the resulting mess in the comments.
Right! There is a lot to cover with this topic, and I couldn't fit it all in, so i'll split this into two parts. I can put more things into this guide and you guys can learn more, as well as give me more time to add activities and such for the next part.
Part 2 will involve shading ponies, finally and will go through the different types of light directions we can use. It'll take an entire part on its own, but it'll get done. Watch this space! I'll have it as a separate post.