Jun 21, 2021

Two new metrics can help us remember the night

By Jane Slade

Darkness as a BeaconAs a child, I remember first learning about the Impressionist movement through Vincent van Gogh’s painting, Starry Night. We learned how at first his work was rebuked and then slowly people came around to revere it, and that of course, he never got to know. Van Gogh spoke freely of his love of the night, and the power it had to inspire his imagination, saying, “for my part, I know nothing, but the sight of the stars makes me dream,” and “when I have a terrible need of – shall I say the word – religion, then I go out and paint the stars.”

I remember studying those swirls of painted stars with my younger eyes and feeling actual comfort that this freedom of expression came from an adult. People have felt inspiration from this work across the world, reproducing the painting in countless forms, in reverence to the imagination of Van Gogh’s mind at that very moment of seeing the stars, an abandonment of reality into whimsy and delight, which is exactly the type of shift in perspective that the night sky provides. Looking at Starry Night now, I feel it is one of the most valuable and important examples of inspiration that was captured from the night sky.

At this moment in history, very few of us could take Vincent van Gogh’s advice and go outside to paint the stars. If most of us live in and around cities, then we live under skies classified as seven, eight or nine on the Bortle Scale, a nine-level classification of night sky visibility, with nine being the worst. In fact, one study showed that more than 80% of humanity lives under skies that are polluted.1 We simply no longer have access to the night sky that Van Gogh painted. How do you measure this loss in inspiration? How do you measure the value of the night sky?

This year marks the 20-year anniversary of the Bortle Scale, a scale in pursuit of dark skies that was conceived and first published by astronomer John Bortle in February of 2001. It is also the 10-year anniversary of the Model Lighting Ordinance (MLO) in June, a document created through a collaboration with the Illuminating Engineering Society and the International Dark-Sky Association to assist communities in the development of more sustainable lighting standards. MLO Lighting Zones divide areas into 5 levels, LZ0 to LZ4, from darkest to brightest. This classification offers a feedback loop for communities to assess and understand their current lighting levels and guide future designs to their ideal, likely lower, lighting levels.

TO THIS DAY, THESE TWO FRAMEWORKS, the Bortle Scale and the MLO, are the nearest quantifications of darkness in use by the lighting industry, exposing a gaping hole in our analysis of darkness. While analogues do exist in astronomy, we simply do not measure or quantify darkness from the starting place of darkness. If we are not tracking darkness with metrics, we cannot bring it into our thoughts and processes to cultivate it. In a world that is being polluted with more light every day, we need to create metrics that enable a feedback loop to foster awareness in support of darkness.

For sustainable lighting practices, the Natural Daylight Cycle is our Rosetta Stone. This perennial balance of light and dark has entrained and tuned the behaviors of all living things on Earth and is the base model to lighting practices that support human activity with the least impact upon nature. In support of this natural balance, I would like to propose two new metrics. Akin to the measurement of energy with kilowatt hours, the metric Unnatural Lumen Hours (ULH) will measure and quantify lumens emitted outside the original balance of the natural daylight cycle, creating a feedback loop of understanding that quantifies impact. In addition, we can measure Full Darkness Hours (FDH), periods of time that have been designed within the 24-hour cycle of our projects to remain at full darkness, providing a metric to quantify, incentivize and support natural darkness.

To regain the natural night, we must also expand our design methods to better support darkness. One of the main mediums of design communication in lighting design is the creation of a “lighting design plan,” with illumination as the starting place of thought. Since natural darkness is exactly half of the natural daylight cycle, dovetailing our design practices with the creation of a new type of drawing, a “darkness design plan,” will balance the arc of thought to better reflect the natural proportion of light and darkness on the planet. Designing with darkness as a starting point is a valuable antidote to over-lighting and encourages a new type of exploration into the art and science of darkness.

We must also explore new methods in utilizing our existing technologies, such as redirecting the intended purpose of lighting controls. Originally, the use of controls boasted additional energy savings beyond LEDs, however this was often not enough to incentivize their adoption on projects. Perhaps we missed the most important incentive altogether, the invaluable benefits of darkness, for which modern synonyms include silence, spaciousness and restoration. Of all lighting technologies, lighting controls offer the most profound gateway to restore natural darkness by providing the ability to light for human activity and to be decisive about lighting only what is needed through experimentation with adaptive lighting controls.

YET, THE GREATEST OBSTACLE TO DARKNESS remains the notion that more light is safer. While this can sometimes be true, this pervasive misconception is fraught with mistruths, unattainable safety, and contributes to the writing of rules and codes that enable light pollution. According to a 2015 study on street lighting in England and Wales, reduction in light levels held little correlation to increases in crime or traffic accidents.2 If the correlation that more light is safer is at best weak, then we are gambling the immeasurable value of darkness and the night sky on terrible odds. What has the night sky inspired in humanity and what is humanity missing by not having access to the stars? How will the lack of darkness be reflected in the quality of our thinking? Perhaps this is acutely more dangerous than the risks of darkness.

We have come upon a unique problem of our time in that we never feel silence; we never feel darkness. We need to incriminate light. It must be debunked within the larger collective consciousness that light at night is not innocuous. It causes great harm upon the environment and the quality of our thoughts. In the dimmer shades of the natural daylight cycle, a more limitless mode of thinking takes place. We become cloaked in the dim light to rest and recover.

There is a departure here that we have stopped taking—to step away from the day and reflect, to feel our own thoughts and connection to the unseeable and the unknowable.

At this moment in history, we have blocked a view of the stars because of the way we utilize our lighting technology. The current mode of thought turns a blind eye to the loss of the stars and to the wonder it provokes, disregarding the value of this natural resource altogether. Maybe our story is not so different than the story of Vincent van Gogh’s Starry Night. Perhaps people will look back on our time in history and liken us to the public who did not yet see the beauty of Van Gogh’s work, except in our case, it will be the night sky itself.

Darkness has been as much a part of our humanity as the light. It is a beacon all on its own, an invitation to wonder and thought that cannot be experienced in brightness. Yet, a return to natural darkness will not just happen; darkness is being subverted by our lighting practices with LEDs. We must reacquaint ourselves with the immeasurable value that darkness holds and cultivate it through new metrics and methods that inspire our thinking from darkness as a starting point. We could all experience the stars every single night if we designed this into our plans. We have all the tools to accomplish this; our lighting technology can support a view of the night sky and darkness. We are simply forgetting to remember the night.


Jane Slade

Jane Slade

Jane Slade, MID, LC, is the specification sales manager for Speclines in Massachusetts, a lighting manufacturer’s representative agency specializing in outdoor lighting for municipalities, universities, corporations, commercial developments and transportation agencies. Ms.... More info »