The indicator species of gentrification are many—pop-up farmers' markets, a front yard with a Little Free Library, thousand-dollar baby strollers. Among the most telling—certainly the most visible to a flâneur at twilight—are Edison-style incandescent light bulbs. Reproduction retro lighting is essential for any restaurateur or publican seeking an upscale clientele. Glowing tungsten filaments seem to draw graduate-degreed urbanites like moths to the proverbial flame—which is more than just a figure of speech, as we'll see.
First, some science. As my wife, architect Wu Wei, explained to me, we gauge the intensity of a light source in lumens and its quality by color temperature. Measured in Kelvin—a thermodynamic temperature scale with a null point of absolute zero (where thermodynamic activity ceases)—color temperature is counterintuitive: The lower the temperature of a light source the "warmer" it appears, and vice-versa. Natural daylight—a mixture of sunlight and skylight—runs from 2000K at sunrise or sunset to as high a 5500K when the sun is directly overhead. The temperature of an ordinary tungsten incandescent bulb is 2400 to 2700K, while that of a tungsten halogen or quartz lamp hovers around 3000 to 3200K. A cool-white compact florescent (CFL) lamp has a color temperature of approximately 4000K. Some early consumer LED units exceeded 6000K.
Light at the higher end of the Kelvin scale appears bracing and caffeinated, the bluish-white light of workplace and classroom. Most people find light of lower color temperature to be warm and intimate—the light of home and snug bistros on Old World streets. It's the raking autumnal light at day's end, easing us sleepward like a glass of wine. This is hardwired in our brains, a function of deep ancestral memories of camp and cooking fires and the cycle of day and night.
But culture also plays a role in lighting appreciation. In China, dim incandescent lighting is still associated by older people with the poverty and hardships of the recent past. A bright home was a mark of wealth through much of Chinese history, while demons like the nian were believed to lurk in dark corners—to be flushed out with lanterns and fireworks at Lunar New Year. Illumination was thus both a prophylactic against evil and a status symbol, which explains why brilliantly lighted shops and restaurants—even upscale ones—are still common in China. Most Westerners (and younger Chinese, less beholden to tradition and with little memory of Mao-era privation) expect low dim light in a fashionable restaurant—light that evokes the ambience of a candle-lit dinner. It is no coincidence that Edison bulbs deliver a color temperature almost identical to the flattering light of a candle flame.
The Edison bulb revival began quietly in the 1980s, when entrepreneur Bob Rosenzweig began manufacturing reproductions for collectors. Sales were thin for years, until CFLs began replacing incandescent bulbs on store shelves. By the mid-aughts, Rosenzweig's products were all the rage with restaurant designers in New York. Then came the 2007 Energy Independence and Security Act, which unintentionally kicked the Edison revival into overdrive. Its new standards for energy consumption effectively banned most "general service" incandescent light bulbs, which became illegal to manufacture or import after 2014. But there were exceptions—bug lights, black lights, three-way bulbs, and "decoratives" such as Edison bulbs.
Like many people, I paid little mind to the aesthetics of light until incandescent bulbs began vanishing. This was driven home to me on a late-night walk in Rome several years ago. Halfway up the Janiculum Hill, I peered into the courtyard of San Pietro in Montorio—home to Bramante's Tempietto, a masterpiece of the High Renaissance said to mark Saint Peter's martyrdom. What should have been a profoundly moving moment was spoiled by the bluish CFLs illuminating the courtyard. The buttery complexion of Bramante's travertine, the tawny cloister walls—all lost in a flood of convenience-store glare.
That glare is spreading; recently, many American cities have begun replacing familiar high-pressure sodium-vapor streetlights with efficient LED units. As of last fall, some six million LED street luminaires had been installed across the nation—most of the super-efficient blue-white type. These have saved millions in energy costs. But people actually liked the "jack-o'-lantern glow" of the old sodium-vapor lamps, and find the new LED light—in the 4000 to 6500K range—to be annoying. Science is on their side, as the new streetlights may contribute to sleep problems, like using a smartphone before bed. As the American Medical Association recently explained, "blue-rich LED streetlights operate at a wavelength that most adversely suppresses melatonin during night," causing five times greater impact on circadian sleep rhythms than ordinary street lamps.
With our streets so amped up with light, it's hardly surprising that we expect our bars and cafés to provide respite from the lumen storm outside. Edison light bulbs are today as much a part of the upmarket consumerscape as cruelty-free cosmetics or cage-free eggs. They are markers that signal the presence of creative-class tribal space. Their soft glow appears to be crafted by artisans from a more earnest age, one caressed by the dim light of steampunk suns.
"You can't ... brag how green you are by serving organic beer and locally grown produce while you are lighting your business with the least efficient light bulbs available in the world."
This is, of course, more than a little ironic. "You can't ... brag how green you are by serving organic beer and locally grown produce while you are lighting your business with the least efficient light bulbs available in the world," scientist Noah Horowitz told the New York Times several years ago. Delightfully complicating this is the recent arrival of solid-state Edison bulbs, which use a thin array of light-emitting diodes instead of a tungsten filament. Indistinguishable from more than a few feet away, they epitomize our tangled obsessions with both technology and an imagined urban past.
Just how accurate a marker of affluence and gentrification are Edison light bulbs? Very, it would seem. I recently walked most of Brooklyn's Flatbush Avenue at twilight looking for the bulbs. The borough's original Main Street, Flatbush makes a 10-mile plunge from downtown Brooklyn to Floyd Bennett Field—Gotham's failed first municipal airport. Much of the route is an unspoken boundary of sorts between majority-black neighborhoods of Bedford-Stuyvesant, Crown Heights, and East Flatbush to the east, and the mostly white enclaves of Park Slope, Ditmas Park, Midwood, and Marine Park to the west. That line has blurred in recent decades, as creative-class elites moved east to reclaim white neighborhoods—Prospect Heights, Prospect-Lefferts Gardens, Prospect Park South—that emptied after World War II.
I found two dense concentrations of Edison-lit shops, restaurants, and cafés on Flatbush Avenue. The first is between Grand Army Plaza and Atlantic Avenue, where Flatbush runs past Park Slope—one of the most sought-after neighborhoods on the Eastern seaboard. There is a second burst of vintage incandescence from Empire Boulevard to Caton Avenue, in the more recently upscaled neighborhood of Prospect-Lefferts Gardens.
The observed density of Edison bulbs, it turns out, aligns precisely with data compiled on Trulia's heat maps of residential property valuation and listing prices. Areas with the highest concentrations of tungsten were reliably ones deep within or on the edges of neighborhoods with very expensive housing. In fact, they map closely to market valuations of a million dollars or more. Once listing prices fall below seven digits, at about Beverley Road, the lights disappear. The last tungsten-bulbed establishment is close by, Forever Ink Bar, at the corner of Duryea Place near the recently restored Kings Theater. This is the southern front of gentrification in Brooklyn. Beyond this point, Flatbush becomes Main Street of one of the largest West Indian communities in the world beyond the Caribbean.
From Forever Ink to Avenue U (a three-mile run, nearly half my walk), I found not a single Edison bulb—none in the hundreds of West Indian shops and eateries; none by Brooklyn College; none in the busy blocks through Orthodox Midwood; none as the avenue glides expansively across the quiet residential terrain of Flatlands and Marine Park. It was as if I had tripped an invisible cultural switch. I came across just one near-exception, a cozy Caribbean wine bar—Sip Unwine—near Ditmas Avenue, but their pendants used regular incandescent bulbs.
The lesson here: In our restless quest for urban authenticity, we might do well to look not for vintage tungsten, which tends to illuminate only the carefully curated small-batch offerings of neighborhood newcomers. Instead, seek the cold white glare of coiled CFLs and ceiling-mounted tube fluorescents. That's the light you'll find in the Guyanese grill, the Dominican bodega, the Fujianese take-out, and the Bangladeshi newsstand—unflattering, unflinching, and altogether real.