#fresnel

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"Flare 40" by Studio Douze Degrés,

Flare is a lighting collection developed by Douze Degrés as part of its research on optics. Inspired by maritime lighthouses, it transforms a simple flame into a luminous signal.

Using an optical lens, the candlelight is captured, amplified, and projected—turning a soft glow into a vibrant beam.

The story of Flare began with an exploration of the visual distortion created by the Fresnel lens. Experimented during a scenography project at 3,600 meters altitude, for a live show at the Sphinx Observatory for Cercle Music.

Anodized Aluminium & Optical Lens, Candle,

You've probably seen pavements with small glass tiles in them. Yeah, they probably lead down to a basement (unless they're just embedded lights), but they also might be hiding a neat bit of optics!

In the era before cheap and plentiful electric lighting, efficient use of sunlight was vital. This period was right around when many cities had major raising projects and basements and accessways were widespread, and they needed cheap lighting. Therefore, the sidewalks that were built at the same time had pavement lights integrated.

The earliest pavement lights were exactly what you might think: Thick glass tiles that simply let some sunlight through. Beneath them are what's termed a 'sidewalk vault'. Usually that's a place that used to be the old sidewalk, but now has a new street constructed several feet above it.

Well, the 1870s saw a big improvement in these lighting systems with the integration of optics. Fresnel lenses could be shrunk down to a single glass tile and embedded in the sidewalk. So now where sunlight used to only be able to get to something directly below the sidewalk light, now it can be redirected and spread through the entire space below!

This wasn't a wholly new invention. It actually saw use earliest as deck prisms installed on sailing ships. A sphere of glass installed in a ship's deck would catch sunlight and scatter it to lower decks, which would normally be extremely dark, especially somewhere that can't have open flames. The shape was often handmade, since this came before industrial glass manufacturing.

More complex forms of these came about as entire sheets of Fresnel lenses that were designed to perfectly illuminate the basement with what little light hits them from above. A 'prescription' of lens had to be identified prior to installation.

And then someone figured, why not use this same logic for vertical windows to better light the interiors of buildings too? This lead to anidolic lighting, which this textbox doesn't think is a word. If you find a very old department store, try looking for a second row of thick glass tiles on a single level. These might be anidolic lighting prisms which catch sunlight and angle it to better hit the back of the room.

Anidolic lighting fell out of fashion by the 1930s as everyone could just install electric lights which work all the time instead. Most sidewalk lights today just get paved over with concrete when the surface is refinished or the prisms are broken. And the old department stores are getting remodeled or torn down.

But efficient lighting systems are making a resurgence today! You can have a light tube on your house which is capped with a sphere to catch and redirect the light exactly as the old sailing ship deck lights did.

For an even simpler installation, there are simple plastic sheets which can be applied to a window. Their secret is that they're covered in an extremely thin layer of Fresnel lenses too. The tiny ridges will take light hitting the window from the side and redirect it, just like the old department store windows.

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