The Building Blocks of Interior Design: Light
How Light Changes What We See and How a Room Feels
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In The Building Blocks of Interior Design, I described the seven elements of interior design. Designers use these elements to create rooms that are comfortable, balanced, functional, and beautiful.
No one is born knowing how to hang drywall—and no one is born knowing the elements of interior design and how to apply them.
Like any skill, the elements of interior design can be learned and used to create a home that’s functional and beautiful.
Including your home.
In this post we’ll cover the element of light and how to use it in your home.
What is Light in Interior Design?
Light is a form of energy that determines what we see.
What we see strongly influences how we feel in a space.
You don’t need a physics degree to design a well-lit room, but understanding how light behaves can help explain why light changes what we see—and how a room feels.
How Light Behaves When It Encounters the Stuff in Our Homes
When light encounters a surface, it will interact with the material covering the surface in several ways:
Reflection — how light bounces off of surfaces.
Absorption — how different materials take in light.
Transmission — how light passes through different materials.
Scattering/diffusion —what happens when light is redirected in many directions.
Refraction — how light changes direction as it passes from one material to another.
Now let’s cover how to leverage light to make your home look and feel better.
Reflection—How Light Bounces Off Surfaces
You already know what reflection is. Just look in a mirror.
When you look in a mirror, light strikes your face and bounces from your face toward the mirror, which reflects that light back toward your eyes. Your eyes and visual cortex interpret those reflected rays as though they continue behind the mirror, which is why your image appears to be in the mirror.
Cool, right?
Reflection happens when incoming light hits an object and is redirected in a predictable direction. Mirrors are optimized to reflect light in an orderly way, but virtually every surface reflects some light, depending on its luster, color, texture, and material.
The more lustrous and glossy a surface is, the more directional its reflection. For example, the light reflected off a lacquered cabinet’s surface is more concentrated and directional than the light reflected off a wood cabinet—so our eyes see more highlights and contrast when looking at the lacquered cabinet.
A polished kitchen countertop creates more visible reflections and highlights than a honed countertop, making it feel brighter, livelier, and more visually active.
Lighter-colored surfaces reflect a greater proportion of visible light; dark surfaces reflect less visible light. That’s why rooms with lighter walls can feel larger and brighter and rooms with dark walls can feel cozier and more enveloping.
Textured objects scatter light in different directions instead of bouncing it back in an orderly direction like a mirror. This is called diffuse reflection and I’ll cover it in more detail in the Scattering/Diffusion section below.
The material of an object or surface also affects its reflective properties. Metals are highly reflective because of the way their free electrons interact with incoming electromagnetic waves. Nonmetallic materials can reflect, absorb, scatter and—in some materials—transmit light to varying degrees.
Because matte and textured surfaces produce fewer sharp highlights and more diffuse reflections, they can appear quieter and less visually active than glossy surfaces. Used in a room, they can make a space feel more grounded and intimate.
Absorption—How Materials Take in Light
Absorption—specifically, selective absorption—plays a major role in determining the colors we see.
Different light sources, like sunlight, candles, and light bulbs, all produce light energy in different mixtures of visible wavelengths. When light hits an object, that object absorbs some wavelengths and reflects others back to your eyes. Your brain interprets those reflected wavelengths as color.
For example:
A red object absorbs most of the other visible wavelengths and reflects more red light toward our eyes.
A white surface reflects a relatively broad range of visible wavelengths, which we “see” as white.
A black surface absorbs a relatively large proportion of visible wavelengths and reflects relatively little light back to us.
When we “see” color, what we are really seeing is the light that reaches our eyes after interacting with the object or surface we’re looking at.
Absorption also explains why colors “look” different depending on the amount and type of available light. A surface or object can’t magically produce the light wavelengths that make it “look” a certain color—which is why your blue office walls, green leather chair, or maple hall console look different depending on whether they are lit by morning, afternoon, or artificial light.
It’s also why I default to neutral temperature lighting (3500-4000K) in my home to minimize color shifts in my home’s interiors under artificial light.
Because dark objects and surfaces absorb more light and reflect less of it back into the room, they can make a space feel darker (obviously!), but also quieter and more intimate. When used with intention, they can create a sense of coziness and enclosure; when overused, they can make a room feel gloomy.
Transmission—How Light Passes Through Different Materials
Transmission is the process by which light passes completely or partially through a material rather than being reflected or absorbed.
Transparent materials like window glass allow most light waves to pass through, which is why you can clearly see the outdoors from your living room window.
Translucent materials, like frosted glass or sheer window panels, let light pass through them but scatter the light in different directions, which is why images look blurry when seen through them.
Opaque materials reflect or absorb light waves, blocking light from passing through them.
Transmitted natural light can affect how open or enclosed a room feels. An unobstructed window maximizes natural light transmission to brighten a room and visually extend the room’s boundaries by letting the outside in. Frosted window glass can eliminate that visual extension to the outdoors, while sheer draperies soften it, even though both still allow some natural light into the room.
Transmission allows you to control the relationship between light and privacy in a room. Opaque window treatments minimize natural light and maximize privacy; no window treatment maximizes natural light and minimizes privacy; sheer window treatments do a little of both.
Scattering/Diffusion—How Light Gets Spread Around
Scattering/diffusion describes what happens when light is redirected in many different directions rather than remaining concentrated.
Light waves move in a straight line until they hit a surface or object. If the object is transparent, most of the light waves pass through the object with minimal diffusion; if the object is translucent, light waves will diffuse (or scatter) in different directions.
When the light scatters, concentrated light becomes softer, more even illumination.
Lampshades are a great example of diffusion in action. Simply remove a lampshade and turn the lamp on. The light emitted from the bulb is concentrated and harsh and can seem overly bright. Replace the lampshade, and the light from the lightbulb is instantly softened and less concentrated.
Frosted lightbulbs, frosted windows, sheer curtains, even a cloudy day are also examples of diffusion in action.
Why does diffuse light feel different from, say, a hard beam of direct sunlight? That’s because diffused light reduces shadow and glare and evens out illumination, making rooms lit with diffused light more relaxing.
Refraction—How Light Changes Direction
Refraction describes how light bends or changes direction as it passes from one medium to another.
A great example of refraction is a rainbow. When sunlight enters water droplets in the sky, the light slows down and bends. Different wavelengths bend by different amounts, separating the light into the colors we see in a rainbow.
Another familiar example is a pencil partially submerged in a glass of water. The pencil looks bent at the water’s surface because light changes direction as it passes from the water into the air on its way to your eyes.
In our homes, the most common examples of refraction are how light behaves when it encounters crystals or crystal lighting. I keep a teardrop-shaped crystal on my kitchen windowsill because I love how it turns the morning sunlight into tiny rainbows. When lit, the crystal chandelier in my bedroom creates rainbows of light on the ceiling.
Refraction enables little moments of magic.
How to Use Light in Your Home
Let’s sum up how leveraging light can change how a room feels.
Lighter-colored walls reflect more light; dark walls absorb more light. Choose lighter colors to make a room feel larger and brighter and dark walls for a cozy vibe. Beware overusing dark colors as they can make a room change from cozy to gloomy.
Glossy surfaces attract the eye because they provide higher contrast and highlights. For example, a polished kitchen countertop can make a room feel brighter and livelier than a honed countertop.
Metals are naturally reflective due to their physical structure; using metal objects can enliven a space.
Matte and textured surfaces appear quieter and less visually active than glossy surfaces and can make a space feel more grounded and intimate.
The colors in your home will look different depending on the type and availability of light in your home, which is why your home will look different in morning, afternoon, or artificial light. If you want to minimize the shift in color in your home when using artificial light, use neutral temperature lighting in the 3500-4000K range.
Unobstructed windows visually brighten a room and extend its boundaries but offer little privacy. Use window treatments to tweak the balance of light and privacy in your home.
Diffusing your light sources with lampshades, frosted glass, frosted lightbulbs, or sheer curtains reduces shadow and glare, evens out illumination, and makes a room feel more relaxing.
Use crystal lighting to create little moments of visual delight, like the little rainbows that dance over my kitchen cabinets thanks to my teardrop-shaped crystal suncatcher. If you have a large window that gets good sun, this rainbow maker is fabulous (I got one for my sister).
Light isn’t something we simply add to a room to be able to see.
Light changes what we see and how we feel in a space.
Light is an integral part of your home’s design that can change how you, your family, and your guests perceive its colors, materials, textures, and objects.
Understanding how light behaves can help you create a home that feels good for everyone.
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The Building Blocks of Interior Design: Texture.
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