Reflected Light: A clear-cut explanation for painting reflected light 2021

Reflected Light - A clear-cut explanation for painting reflected light

Welcome to Reflected Light with CecelyV!

Hello and welcome, fellow artists! Thank you for taking some time to read my article on reflected light.

There is a lot to understand about The Fundamentals of Light and The Fundamentals of Art, and sometimes it can all feel large and overwhelming. In this article, I’ve broken out reflected light, a small and vital piece of light fundamentals, to explain and demonstrate what it is and how it works.

I hope to help you build your understanding of light one small step at a time, so it all feels less daunting. To make this article helpful, I’ve kept the focus narrow. This article is only about reflected light. I’ll explain what reflected light is and how it’s different from other light effects, and I will give examples and demonstrate how to paint reflected light.

Understanding light

To fully understand how light works, we need to study it. In my Fundamentals of Light article, I explore and explain the basics of light fundamentals. But, first, let’s review a few points that will help with understanding reflected light.

Light source

A light source is anything that produces its own light. Typically, we draw and paint light effects from familiar natural sources such as the sun and fire and artificial sources like light bulbs.

Each light source has its own properties and characteristics, and most produce a lot of heat to emit light. A couple of exceptions are bioluminescence and chemiluminescence, which see light photons produced without much or any heat (“cool light”). We see bioluminescence in fireflies and jellyfish, and we see chemiluminescence in glow sticks.

Reflectors

Objects and organisms that do not create the light that comes from them are called Reflectors. So, for example, our moon, mirrors, eyes, and other things with reflective surfaces are all reflectors–they all reflect light from a light source but do not emit (or produce) any light of their own.

Understanding light means exploring light sources as well as objects that act as reflectors.

Light rays

reflected light - light rays
Rays of strong sunlight

Light always travels in a straight line called a ray. However, the direction of light rays is changed through reflection and refraction, and what I’m covering is fundamental light reflection.

Direct light and Indirect light

For a surface to receive direct light means there is nothing between the light source and that surface. Therefore, the lighting is directly contacting the surface with no interference to affect the direction of the light rays.

Indirect light is light that is being diffused or reflected in some way before it reaches the lit surface–its direction is changed. This means before light hits an object’s surface, there is quite a lot of light bouncing around off other surfaces.

A sunny day experienced through a bedroom window is an example of indirect light. The sun’s light is being diffused and reflected off clouds, the atmosphere, the ground, the window glass, and the bedroom walls and objects to light the bedroom. The light source, in this case, the sun, is not shining its light directly into the bedroom, but its light is illuminating the room in an indirect way.

Primary light source

In the example of a bedroom on a sunny day, the primary light source is the sun. There aren’t any other light sources acting on the bedroom in this scenario. When light bounces off so many surfaces to illuminate an area like that it’s also an example of ambient light.

When lighting a scene, the primary light source is the strongest (most intense and bright) light source that is responsible for most or all of the light and shadows occurring. A primary light source can be any type of light as long as it is the main source of lighting.

Secondary light sources tend to be smaller, closer to the subject, less intense, and less bright.

What is reflected light in art?

Reflected light in art is the same as reflected light in nature. The only difference is nature doesn’t need tutorials like we do 😉.

Reflected light happens when light emitted from a source bounces (or reflects) off objects and surfaces and illuminates other areas/surfaces/objects with that reflecting light.

Here are some examples of reflected light.

What is the difference between light and reflected light?

Context, intensity, and whether or not absorption is happening are the main differences between the terms “light” and “reflected light.”

Light and reflected light in context

When we refer to light, we’re usually talking about a light source–something that is producing and emitting its own light that we can see. So, when we say, “turn on a light”, “light a candle”, or “hand me that flashlight” we know we’re talking about light sources like lamps, candlelight, or a flashlight.

If you were to walk into a bedroom ambiently lit as in the earlier example, you’d probably say the room appears “bright” because of the light falling through the bedroom window and light bouncing off various reflective surfaces. It’s not likely you’d say, “what a nice bedroom with reflective light.”

So, the context is important. Typically, we don’t refer to most lights as reflected lights unless we are specifically calling out the fact that light is being reflected.

Intensity

There is a significant difference between the intensity of source light and that of reflected light. Source light loses most of its intensity when it begins bouncing around off surfaces and objects, so reflected light is much weaker than the source that creates it.

An exception to this rule happens when light is bounced off a highly reflective surface, such as glass or water.

Absorption

Let’s use direct sunlight as an example. When it is reflected (or bounced) off highly reflective surfaces such as water, glass, or a mirror, direct sunlight loses little to none of its intensity because almost none of the sunlight is being absorbed by those materials. It is all being reflected.

Most reflected light we see has been bounced off surfaces with considerably lower reflectivity than water or glass, meaning much of the light is being absorbed. The absorption results in lost intensity for the bit of light that gets reflected, which is why reflected light appears so much weaker than source light.

What is reflected color in art?

This isn’t really a thing. “Reflected color” is really just light that has reflected off a colored object and taken on the local color of that object, or it’s colored light that is being reflected or both. We cannot see color–or anything else–without light, so there is no such thing as “reflected color” only reflected light that has a color.

What is reflected light in drawing?

Reflected light is the same whether you’re drawing or painting, or observing light in real life. The medium you use to describe light in your image doesn’t change the behavior of light. Reflected light in a drawing is still light that is coming from a source and being reflected off an object or surface to illuminate another area, surface, or object with the light reflected.

The main concept to understand with reflected light is the light’s behavior when it is being reflected, and the materials it is reflecting off of. Technique changes with the medium used, but the behavior of light will remain consistent and predictable.

What is the difference between reflections and reflected light?

The reflectivity of the object/surface material and the light intensity involved is what separates reflected light from what we usually call a reflection. The behavior of the light is the same for both, but the refractive index and reflectivity of materials play a big role in how light’s behavior is conveyed to our eyes.

With reflected light, we see an indication of an object’s reflection on a matte surface, whereas we see clear to mirror-like forms with reflections.

Examples of Reflection vs. Reflected Light

Differences and changes in materials’ characteristics can alter light’s direction and the appearance of reflections. As you can see in the images below, the quality of reflected light and reflections is noticeably different as materials, form, and light intensity change.

Below are more images to demonstrate the differences between reflected light and a reflection.

In the first image, everything above the horizon–sky, clouds, mountains, and treeline–is reflected perfectly on the mirror-like (specular) flat surface of the lake’s still waters.

In the second image, we have much the same effect but with even more reflections happening on the glass sphere. The spheric form and highly reflective–and transparent!–quality of the glass further alter the direction of the light through refraction as well as reflection, so there’s a lot going on there.

The same is true of the third image, but the soap bubble has an additional characteristic of iridescence that drastically alters the appearance of the reflections cast upon its surface.

All three images show highly reflective materials, each with its own sets of characteristics that greatly impact the quality and appearance of the reflections.

The next three images show how changes to the materials can alter the specularity of the reflections, creating more of a Lambertian effect.

In the first image above on the left, we have an evening/night scene with artificial light reflected on the surface of a large body of water. In our earlier example of light reflected off water, we had a daytime scene and still water that created a mirror image of the objects above the horizon line. In this image, the water is not still and the light sources are smaller and less intense.

This change to the material and light intensity creates a Lambertian reflection rather than a specular reflection. The main difference between the two is the texture of the surface material receiving the reflection. The water is still highly reflective, but it is now choppy and textured instead of still and smooth and that creates more of a matte (diffusely reflecting) surface on the water.

Smaller, lower intensity light that is bouncing around more on a now matte surface means we see reflected light on the water rather than reflections of forms.

The next image with a person’s reflection on wet sand applies the same principle. The surface material here is actually wet sand, not water. Sand is not reflective, but soaking wet sand on a shore when the tide is in? That scenario combines the texture of the sand with the reflectivity of the water, and we get a reflection that is somewhere between Lambertian and Specular.

The last image shows a wooden cylinder next to a purple plastic cup. The cylinder has a matte surface, the plastic cup shiny and reflective. When lit and placed near each other, we see reflected purple light (Lambertian reflection) on the wooden cylinder, and a more specular form reflection on the plastic cup.

Notice on the cup we can clearly see the reflection of the wooden cylinder, the light source, and a couple of other items on the shadow side of the cup. All of the reflections on the cup also have a purple tint, reminding us that local color for each object is always a factor.

Understanding how reflected light works

First things first, let’s review some basic light and shadow terminology, shall we? In the image below, I’ve labeled all the stuff and gubbins and you can always refer to my Fundamentals of Light article if you need an in-depth explanation.

We’ve discussed materials, reflectivity, and light intensity as a few factors that affect how light reflects. A couple of other factors to consider when we’re studying reflected light are distance and position.

The next few callout images demonstrate how the distance between objects impacts the amount of reflected light that is able to reach the subject.

In this next round of callouts, I’ll demonstrate more about how object position and materials affect reflected light.

You might have noticed that most of the time when we observe light bouncing onto an object or surface it does so in the form shadow (dark side, shadowed areas) and/or in the cast shadow areas. The reason is all about positioning. When one object is in front of another it will cast a shadow on that object, reflecting little to no light onto it. This is because the light falling on any object will reflect out at the same angle it came in (Law of Reflection).

In the image with the red box and the wooden cylinder, we see a slight exception because of the proximity of the objects. The intensity of the light, and the proximity of the objects to the light source and to each other, means the light is able to bounce around from the source to the cylinder, to the box, and back onto the cylinder giving the red box’s cast shadow a red tint.

Since materials play such a big role in how light interacts with objects, it’s worthwhile to examine a few more instances of how changes to material characteristics affect everything from form shadows to cast shadows, to the tint and shade of reflections and shadows, and the edge of a shadow or reflection.

Light transmission is a separate but obviously related light effect. When materials are translucent or transparent light is allowed to pass through to varying degrees, and can then bounce around on other objects and surfaces. Since it is a separate area, I won’t lose focus by delving into it here, but I thought it would be helpful to offer a few examples so you’ll know the differences in the light effects you observe as you study and practice the Fundamentals of Light.

How to paint reflected light

I created a basic demonstration that I hope helps bring all this together in a simple example. My demo uses simple matte forms so the focus remains on reflected light. Painting reflections and specularity are a whole other demonstration and require a lot more explanation of additional factors like global illumination, so I’ll save that for another time.

Just a few more points

I wanted to mention a few things about local color, colored light, and shadows. In my examples and demonstration, I focused on how light reflects onto objects rather than in shadows or on surfaces. It’s important to mention that the same behavior happens in shadows and on surfaces as on objects. Even a dark shadow can be illuminated with some reflected light, and create interesting visual tonal contrast.

One exception to this, however, is occlusion shadows. The absolute darkest part of any image is where no light can reach– and bounce light is far too weak to penetrate occlusion shadows. Darker shadows will still have color and temperature even if they aren’t illuminated in any way (shadows aren’t really black), and they are still impacted by the local color of the object casting the shadow and the surface the shadow is being cast upon.

When the light source is a colored light, like blue light or the yellow light of the sun, the hue and temperature of the shadows and bounce light will be affected. Of course, we must still account for light intensity and changes to materials.

These are all things we should keep in mind as our understanding and practice of lighting effects grows, and there are a lot of moving parts. If it feels overwhelming, just break down your practice into smaller steps with fewer factors and build up over time.

At first, I recommend tackling basic lighting and simple bounce light on objects, in forms shadows, and in cast shadows with matte materials.

Another Light and Shadow installment, signing off!

As always, Thank you so very much for stopping by my site and reading what I hope you found to be a great article. If not a great article, I hope you found it helpful. If it wasn’t helpful, then yikes! Please let me know that, too, so I can find areas to improve.

If you have any questions, need guidance, or have feedback for me, please send them in the comments section below. I would love to hear from you.

Good luck and best wishes on your practice! Stay safe, take care, and happy drawing!