Intro to Lighting Design: Qualitative & Quantitative Principles

Two foundational principles of lighting design guide guide proper lighting design plans, the qualitative (aesthetic) and the quantitative (engineering).

The qualitative part pertains to ensuring that a space has a pleasing ambience. It is the artistic interplay of shadow and light, darkness and illumination, figure and form.

The quantitative part revolves around providing adequate light for a space. The Illuminating Engineering Society (IES) of North America publishes guidelines of recommendations of light levels requirements for many tasks and activities based on the nature of the space.

In practice, these two principles are often in tension: too much light undermines atmosphere, while too little compromises utility.

If the work of lighting design is left to services engineers to meet quantifiable regulation-determined light output requirements per application, then interior and exterior architectural spaces become soulless environments. Using qualitative measurements, architects and lighting designers should make sure that the architectural intention and aesthetics of a space be stimulating and motivating.

Put simply, when designing the lighting of a space, ask yourself, (1) what are the light fixture and light output requirements of the space (quantitative), and (2), how will the space meet the subjective, psychological experience of the occupant (qualitative)?