So here's the surprise (I'm not one for suspense): though we all accept that he was the 'inventor' of the light bulb, by the time Edison began his experiments with light bulbs, the general structure and technology for incandescent bulbs was already in place: a glass bulb evacuated of oxygen housing a filament of carbonized material that would glow but not burn when electrified. The crucial developments that laid the groundwork for Edison's success were achieved by more than a dozen scientists throughout the 19th century, most prominently by a British scientist named Joseph Swan, whose earlier published research was similar enough to Edison's prototype that he eventually won a court victory in Britain granting him partnership in Edison's UK business, very much against Edison's will.
To Edison's credit, while he was a canny self-promoter, he also coined the phrase, "genius is 1% inspiration and 99% perspiration," which is an accurate and fair description of how he succeeded. He may have relied in part on the inspiration of his peers and predecessors — after all, many inventors and developers do — but he set himself apart with tireless research and experimentation. Joseph Swan's bulb had all the necessary components to function, but it didn't last very long. Edison determined that the key to creating a commercially viable bulb was finding the right material for the filament, one that would last for a long time before burning out. He contacted biologists for help in his search, and by his own count, he ultimately tested the carbonized filaments of more than 6,000 plant species in his search for a long-burning material. He finally settled on bamboo, and in 1880 he created a 16-watt bulb that could burn for over 1200 hours, finally a technology superior to the gas lamp and marketable to the general public.
Edison was embroiled in litigation and other vagaries of competition for the next couple of decades, but the incandescent bulb was already a massive success, especially as other scientists continued to improve on the technology, developing tungsten filaments that burned even longer than the bamboo and that didn't blacken the inside of the bulb.
Other than these refinements, though, the incandescent bulbs we use today are essentially identical to those developed by Edison in 1880. Reproduction "Edison" bulbs look different because instead of double-wrapping six feet of tungsten filament into a tight coil, they have the filament stretched out and visible, formed into scribbly lines or primitive shapes. Some of them even use old-fashioned carbon filaments instead of tungsten. They also typically have vintage-inspired bulb shapes, like the above reproduction from Rejuvenation that features a hand-blown look reminiscent of Edison's own prototypes (Edison had a glass-blowing studio in his laboratory where glassmakers churned out bulb after bulb for his constant experiments.)
In the last twenty years, the reproductions have gotten popular especially in restaurant design, perhaps illustrating a parallel between the simple, rustic, vintage feel of the bulbs and the slow food/farm-to-table emphasis of American cuisine. There have even been several articles about how the Edison bulb is "played out" in restaurant design, including one in the New York Times last year.
While the technology has been basically unchanged for 130 years, that's about to change. Incandescent lights — not just Edison bulbs — are notoriously inefficient: they put out approximately 90% of the power they consume as heat, not light. As a result, the US government and governments around the world are phasing them out in favor of CFLs (compact fluorescent lamps) which are much more energy- and cost-efficient. Ikea has also declared that it will no longer sell incandescent light bulbs.
It's interesting to see such a direct conflict between our desire for green technology and cost-efficiency and our aesthetic tastes, which clearly favor the kind of light given off by incandescent bulbs. Hopefully designers and engineers will continue to perfect the existing CFL technology to bridge that gap. So far my favorite 'compromise' example is the Plumen bulbs (above), whose exposed coils bring the rustic charm of Edison's invention into the 21st century.
Images: Hannes Grobe via Wikimedia Commons; Swan's and Edison's prototypes via the Science Museum, London; Library of Congress print via incwell.com; Rejuvenation; The NYC restaurant Craft, designed in 2001, photo by Joshua Bright for the New York Times; Plumen
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Originally published 6.28.11 - JL