Check out this really clever and well-produced video from YouTuber DIY Perks of how to build an “artificial sun” effect:
One of the best and most understandable discussions of daylight that I’ve seen yet.
Indeed, this combination of two key effects – crisply delineated shadows from co-linear rays of brilliant white light filled in with the Rayleigh scattering of the blue sky dome – is what most people are thinking of (should I say “feeling”) when they request “natural light” in their projects. Yet somehow the architectural lighting industry has dumbed this down into a weak CCT/spectra/melanopic dose discussion while continuing to obsessively focus on “low glare” as some sort of scientifically proven end-all, be-all goal. Glare is a wonderful thing when it is called sparkle.
I would guess the same foundational principles are used in the Coelux skylight.
When my team at Philips Lighting completed the huge Rijksmuseum project back in 2011-2012, we specifically used a single, extremely compact LED package in the tracks spots to produce crisp, single line shadows.
This single aspect of the lighting helped make the light feel natural – the shadows, textures, sculptural relief of the art work throughout the museum all looked sharp and visually crisp. The original lighting design from Rogier van der Heide and the ARUP team also called for uplighting the vaults throughout the museum. We consciously chose to use the same CCT and CRI for both the directional spotlighting and the indirect ambient infill light, to ensure that guests could evaluate the artwork as consistently as possible throughout the museum. But if we wanted to create a much more dramatic effect, we certainly could have change the indirect uplighting to a much higher CCT. For the museum application, we made the right choice, to keep guest focus on the art, not the surrounding environment. But for other applications like retail, hospitality or commercial projects, designers should consider such a dual-effect approach. It doesn’t have to be as crazy perfect at this example – perfectly parallel non-converging optics are excessive – but including spotlights using single LED engines and optics in combination with indirect lighting or illuminated area lights makes a dramatic, visually appealing effect.
UGR calculations be damned!