The Electromagnetic Spectrum — Where Visible Light Lives

The electromagnetic spectrum is vast. It runs from radio waves — with wavelengths measured in kilometres — all the way to gamma rays, measured in fractions of an atom. Visible light, the only portion your eye can detect, occupies a band so narrow it is almost absurd: 380 to 700 nanometres, sitting between infrared and ultraviolet.

You cannot see 99.9965% of the light that exists. But it affects your spaces nonetheless.

Below the visible range sits infrared radiation — heat. Every light source emits some infrared, and poorly specified sources emit a great deal of it. This is why certain downlights make guests uncomfortable in restaurants, why food display cases require carefully managed beam temperatures, and why some retail environments feel physically warm in a way that drives customers out rather than drawing them in. Infrared is invisible but felt.

Above the visible range sits ultraviolet radiation. UV degrades materials over time — it fades upholstery, discolours artwork, breaks down natural fibres, and yellows plastics. In museum and gallery lighting, UV-free specification is non-negotiable. In retail and hospitality, it is frequently overlooked until the damage is already done. The cost of reupholstering a lounge or restoring a display is almost always higher than the cost of specifying correctly from the start.

Modern LEDs have largely addressed both concerns. They emit minimal infrared in the beam and virtually no UV. But not all LED products are equal, and not all claims are verified. When specifying for sensitive environments — art, food, fabric, heritage materials — ask for measured data, not marketing language.

The visible spectrum is where your design lives. The invisible spectrum is where your specification discipline is tested.

Great lighting specification begins where human vision ends.