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Few people think twice about the barcodes on their shopping, but in the 75 years since they were first dreamed up, they have helped save lives, gone into space and stoked fears of the Antichrist.
Lasers. That's what supermarket staff need, insisted Paul McEnroe. Scanners in the checkout and little pistol-shaped laser guns, too. Point, shoot, sell!
In 1969, it was an outlandish vision of the future: these lasers would scan weird little black-and-white markings on products that McEnroe and his colleagues at IBM had designed. It would speed up supermarket queues, he enthused. The solution would come to be known as the barcode.
At this point in history barcodes had never been used commercially – though the idea had been brewing for decades following a patent filed on 20 October 1949 by one of the engineers who was now part of McEnroe's team. The IBM engineers were trying to bring barcodes to life. They had a vision of the future where shoppers whizzed through the checkout with lasers scanning every item they wanted to purchase. But IBM's lawyers had a problem with the future.
"No way," they said, according to McEnroe, a now-retired engineer. Their fear was "laser suicide". What if people intentionally injured their eyes with the scanners and then sued IBM? What if supermarket staff went blind?
No, no, this was a mere half-milliwatt laser beam, McEnroe tried to explain. There was 12,000 times more energy in a 60-watt lightbulb. His pleas fell flat. And so he turned to Rhesus monkeys imported from Africa, though now he can't remember how many. "I think it was six," he says. "I couldn't swear to that." After tests at a nearby laboratory proved that exposure to the tiny laser did not harm the animals' eyes, the lawyers relented.
And that is how the scanning of barcodes became commonplace in supermarkets across the US, and ultimately the entire world.Barcodes have always upset some people. To a fanatical few, they are nothing short of evil
In an unexpected twist, the laboratory used by McEnroe subsequently told him it would be sending him the monkeys. They were his problem now. "It was crazy," he recalls, laughing. "I found a zoo in North Carolina."
Alongside the monkeys, each human member of McEnroe's team at IBM also deserves credit for the Universal Product Code (UPC), as their version of the barcode became formally known. Among their number was Joe Woodland, the engineer who dreamed up the early concept behind barcodes decades earlier, after drawing lines in the sand on a beach. It was he and another engineer who made the application to patent the fundamental idea for barcodes back in October 1949.
Crucially, George Laurer and other members of the IBM team then took this pre-existing proposal for barcode-style markings and developed them into a neat rectangle of black, vertical lines corresponding to a number that could uniquely identify any supermarket item imaginable. From tins of soup to boxes of cereal or packets of spaghetti. The grocery industry formally adopted the UPC in 1973 and the first product bearing one was scanned at Marsh Supermarket in Ohio in 1974. From there, it conquered the planet.
How to read a barcode Every time a laser beam flashes across the face of a barcode, an intricate yet complicated process occurs in a matter of milliseconds. A UPC barcode is composed of black vertical lines, which are either thick or thin, to produce a machine-readable version of a 12-digit number along the bottom – a kind of visual Morse Code. At either end are "guide bars" that tell the scanner which direction it should read the code, meaning it can work even upside down. Between these, the first six to 10 digits correspond to the company or brand owner, the following one to five are the item number and the last is a check digit formulated based on the previous 11 numbers. Once the scanner has read the number, a computer uses it to look up the product in a database that will contain further information such as, crucially, its current price.
Other kinds of barcode soon followed and the UPC also laid the foundations for so-called "2D barcodes" such as QR codes, which can encode even more information. But the history of these little black-and-white markings is far wilder and rockier than you would ever imagine.
You could even argue that it began with the Central Intelligence Agency (CIA).
"I was scanning things for the CIA," explains McEnroe. "Great big maps." That was one of his first jobs at IBM, involving image scanners. As he explains in his book about the invention of the UPC barcode, this helped to prepare him for working on completely new, but related, technology that would revolutionise the retail industry.
BBC Report
McEnroe knew that checkout lines in stores would move much more quickly if staff could just scan products into a computer rather than having to read the prices stamped on each item and then manually process the sale. To be accepted, such a code-scanning system would have to work pretty much every time – and read the code correctly even if the product was pulled across the scanner at speeds of up to 100 inches per second (2.5m/s).
The IBM team set to work, drawing on the design patented by Woodland and his colleague – however, with an important difference. The original approach relied on reading the thickness of the black lines. One of the concepts they had proposed in the patent – a round, bulls-eye style barcode formed of concentric circles – had even been developed by a competing group. But this had proven difficult to print and even harder to fit neatly onto product packaging.
The IBM team worked out that it was easier to print vertical lines and base the scanning process not on measuring the thickness of those lines but rather the distance between the leading edge of one line and the leading edge of the line next to it. In other words, the space between the lines, which was more reflective and easier to pick up by the scanner. That way, it didn't matter if the label printer had too much ink and drew lines that were thicker than intended – the scan would still work, pretty much every time.
While the first barcode-branded product was sold in a US supermarket in 1974, it took another five years for barcodes to reach British supermarkets. As soon as they did, the first item to be scanned there was a box of teabags.
