The seven fundamentals of light
In 2002, Anders Liljefors, professor emeritus at KTH Royal Institute of Technology and Jönköping University, distilled the essence of lighting design into seven principles that continue to guide how we perceive and shape our environments.
Bridging science and light
SAR/MSA and professor emeritus at KTH Royal Institute of Technology and the School of Engineering at Jönköping University, Anders Liljefors has been a pioneer in understanding the relationship between light and human experience. From 1984 to 2002, he developed and led the lighting design programme at KTH School of Architecture, bridging the gap between scientific knowledge of human vision and architectural lighting.
Liljefors introduced the seven fundamentals of lighting design in his 2002 compendium Visual Evaluation: Methods for Visually Inspecting Lighting. These principles provide a framework for assessing light’s role in shaping how we perceive spaces, objects, and textures.
We often take for granted the way light influences what we see, unaware of its profound impact on our visual and emotional experience. Understanding these effects allows us to create lighting solutions that not only fulfill functional needs but also enhance our environments aesthetically and emotionally. Below are the seven fundamentals that guide the creation of effective lighting solutions.
Light level
The interplay between light and darkness defines our perception of a space’s brightness. It sets the tone for activity and rest, influencing our physiological state and mood. The light level must strike a balance that complements the purpose of the space while ensuring comfort and functionality.
Glare
Glare disrupts our visual experience when brightness contrasts exceed what our eyes can comfortably adapt to. It’s essential to carefully position and angle light sources to minimise glare, ensuring both comfort and usability in the space.
Shadows
Shadows add dimension and clarity to our visual world. They define texture, shape, and depth through the contrast between light and dark areas. Whether sharp or diffuse, shadows can enhance a space’s aesthetic and guide the viewer’s focus.
Reflections
Reflections occur when light bounces off surfaces, enriching the visual complexity of a space. The quality of reflections varies based on surface texture; smooth surfaces create sharp, crisp reflections, while rougher ones diffuse light for a softer effect. Harnessing reflections thoughtfully can create striking visual effects and layers.
Light distribution
Light distribution determines how light is spread across a space and shapes our experience of it. The position and type of light source interact with the room’s architecture to create depth and character. A workspace, for example, demands even and functional light, while a retail store benefits from more dramatic distribution to highlight specific elements.
Surface colour
Light interacts with surface colours to shape how we perceive them. Daylight serves as a natural reference for colour rendering, but artificial lighting can dramatically alter a surface’s appearance. Thoughtful lighting design considers this interaction to preserve or enhance a space’s intended aesthetic.
Light colour
The colour of light is both a technical and emotional consideration, shaped by its spectral composition and how it interacts with the space. While preferences for light colour are highly subjective, achieving the right tone is crucial for creating environments that feel welcoming, energising, or serene.
This framework invites us to rethink lighting not as a technical afterthought but as an integral part of design that profoundly influences how we perceive, inhabit, and connect with the spaces around us. Liljefors’ principles remain a cornerstone of modern lighting design, guiding professionals in their pursuit of good light that truly enhances human experience and well-being.