“Most of the time when we are painting, we get so overwhelmed with all the info, which is why practicing the lighting fundamentals beforehand will be beneficial for future work. This will be a pretty lengthy article, but it is pretty comprehensive in terms of necessary fundamentals.
Fundamental #1: Importance of the Plane
When painting and using light, you need to switch from the form build-up approach to thinking about the right plane structure to make the right lighting decisions.
If you can simplify the elements into the proper planes you will understand the structure better and you will be able to assign the right values (when lighting).
Fundamental #2: Light Properties
There are some consideration to make when thinking about lighting. I will try my best to explain some of properties and explain how the lights affect the values and colors of a scene.
Light-Shadow Ratio: The light-shadow ratio determines how much of a contrast there is between light and shadow. A higher contrast is created due to sunlight, and a lower contrast due to overcast weather for example. This is caused by different intensities in light.
Value Keys: Value keying is mainly a design technique used to adjust the value scale while maintaining the light-shadow ratio. Depending on the light situation we have a specific value key in the scene.
Value Compression: Value compression is needed, because we as painters can´t get the full range of light into our paintings. We need to decide, if we want to expose for the light side or shadow side and sacrifice the values on the other side
Light Color: The first thing to understand about light is that it constantly changes it´s wavelengths, therefore changing it´s color. To simplify the process just identify the light as a warm or cold light.
Shading Components
Fundamental #3: Light Set-up
Now that we know how values and colors and affected by light, let´s look at how to set up lighting situations. These lighting situations are always used, and can be divided into natural and artificial light:
Light Types: There are only 3 basic light types you need to know to light your scene. Key Light, Fill Light and Rim Light.
Light Sources: There are only so many light sources that exist. Knowing about them will help you identifying them in any given reference and use them creatively.
Global Illumination: The characteristics of global illumination is the use of bounced/reflected light. It is used to calculate where reflected light is coming from, so we know which planes receive what light in any given scene. You need to treat it as a diffuse light source. It is most effective when there are a lot of shadows.
Fundamental #4: Material Behaviour
Many Material renders disregard the properties of Light. The reason we have learned about light in the first place is to convey materials in different lighting conditions and make them congruent to the scene. Let´s look at the materials and how light interacts with different surfaces.
Learn how to think about shapes, value, color and edges and understand it to apply the knowledge of physics to adjust your values and colors. A proper artist knows both the mechanics of painting and of physics.”
For full explanations complete with image examples, go to the article.
Dunno if anyone’s interested in these, but this was my latest assignment for CGMA’s Art of Color and Light class- this past week focused on how light interacts with different materials.
It’d be cool to try some different skin tones, I just used my own pasty hand for reference. Maybe even an alien species with non-red blood, so the occlusion shadow glows a different color where light passes through? Would it be purple for Namekians and green for Vulcans? (ﾉ◕ヮ◕)ﾉ*:・ﾟ✧ possibilities
Also, the iridescent pearl wasn’t a requirement, but I enjoy Sailor Moon and suffering. If anyone’s got pointers on iridescence, I am all ears over here, because I clawed my way through that one screaming
it’s incredibly useful and very comprehensive so please, check it out!
img 1: sub-surface scattering
Sub-surface scattering – Strong light can penetrate the surface of some materials and bounce around, then exit again. This will increase the saturation and make the surface look illuminated from the inside. In the case with human skin, we sometimes see it on hard edges between light and shadow.
img 2: layer passes
Feel volume and angle of the form.
Where is the light coming from?
Try to figure out if there are any shadows that might be falling on the surface.
Is there any reflected light (radiosity) that hits the surface?
What is the ambient color of the scene? (sorta like global reflected light.)
Any speculars. Is the surface gloss/wet and also angled so it reflects a light source, such as the sky?
The exposure level. Perhaps it’s so heavily lit that it becomes more than white? Perhaps it’s so dark that even the brightest spot is hidden in darkness.
Is there any fog in the way?
The texture of the surface.
Note that this mainly goes for realistic styles. A brushstroke should also look efficient and consistent with the rest of the painting and your color scheme choice. You might also have an idea or style which disallows certain colors or textures and puts priority on other things. However, even in a powerpuff girls illustration there’s simplified elements of realistic rendering. Don’t hide behind “it’s not apart of my style so I’m not gonna learn it”.
img 3: speculars
There’s really just one kind of light. It bounces. You can only see the light (photon) if it enters your eye. Light does two important things when it hits a surface. First, a part of it is absorbed. This is how colors are made. A red apple reflects mostly red wavelengths, the rest are absorbed and turned into heat or something. That’s why black stuff get so hot in the sun. Anyways, the reflected light bounce away differently depending on the surface. If the surface is bumpy it will bounce away sort of randomly, like a tennis ball that hits rocky terrain. If the surface is smooth it will bounce away in a predictable path. A mirror is very smooth so the light comes back undistorted, so we can see our reflection.
Note that all surfaces have speculars, because speculars is just reflected light. It’s just more broken up/diluted on dull surfaces.
img 4: radiosity
Here on earth we have lots of stuff around us that the light can bounce off, so things here are more or less lit from all angles. For example we have the sky which is like a dome shaped blue light source. Then theres the ground, walls and other surfaces. In space there’s basically just one light source, the sun. This is why the moon just has a lit and shadowed side, and looks kind of flat. If you looks carefully however, you can see earthlight on the shadow side of the moon, but it’s very weak. Then there’s starlight, which I guess is even weaker.
When light hits a surface and bounces, it also change color. If it hits another surface of the same color it bounced off, it will make that surface look even more saturated.
Aliquid de Magis 