14. Three (unintuitive) principals for lighting design
Problem: I suspected that a large part of how an interior room feels has to do with lighting as much as the furniture, color and items in the room. I decided to read a textbook about lighting to understand.
Here are a few unintuitive principals about lighting to remember when designing a space.
Humans are attracted to bright surfaces and areas.
We have an instinctual desire to move towards lighted spaces. And it makes sense: evolutionarily, brighter spaces have been more fruitful and safe for us.
One detail I remember from A Timeless Way of Building was to design spaces with the sun in mind. Try it yourself: if you live in a house or space with direct sunlight for part of the day, notice how you feel drawn to go towards it. People gravitate towards sunlight. In my current home, the mornings are nice in the front of the house and the evenings in the rear: matching exactly with the sunlight.
Even though sunlight is the light we are drawn to most, even if you aren’t designing a house from scratch you can still benefit from this knowledge. Create warm, inviting spaces with a high color rendering index (more on that later). Identify where you want people to focus, and place light in those spaces.
2. Brightness is A) subjective and B) about contrast.
Our visual system is effective at adapting to the surrounding light levels. When you’re in a light room, your pupils shrink to let it less light. In a dark room, they dilate to let in more light. The result is that the level of light in a room is not an absolute property. Instead what matters is the contrast between the light applied to surfaces.
This matters mostly to contrast the idea that you need “office lighting”. We’ve become quite conditioned to assume that you need bright, diffuse (spread over a wide area) lighting in our homes because our office and school environments have this lighting.
But in fact you don’t need this lighting in your home. Consider a bedroom. We now understand that we can still accomplish routine tasks like putting on clothing or brushing our teeth with just a bit of contrast in lighting. And if we keep overall light levels low, it will A) create a warmer, more calming environment and B) our eyes will be dilated and ready for sleeping.
3. The perception of light comes from surfaces, and we mostly see vertical surfaces. Focus on these.
Our eyes can’t do very much with light coming directly from a source. Either it’s too bright to process, or we completely miss it. Instead, we perceive brightness through the reflection of light off of surfaces.
This is a different way of viewing the world: light isn’t just
“floating around”. It begins with a source and ends with a surface. A good example is a stage performer with a spot light shown on them. They are bright — and have a lot of light cast on them — but they still feel like they are in the dark because most of the surfaces we see (the floor, the curtains) aren’t reflecting light.
If you look around and could actually measure the surface area of the surfaces that you can see, you’d realize that the majority of what we see is vertical surfaces. We don’t experience the brightness of a space based on the horizontal surfaces (or light shone directly on us), but rather the light reflected off of upright surfaces.
If the goal is to create the impression of brightness, shine light on vertical surfaces. Similarly, if the goal is to create dimness, shine light only on task areas.
