Technology
A pattern of black lines scanned for a tenth of a second can tell a machine everything it needs to know about a product.
Barcodes encode numbers as patterns of black bars and white spaces. A scanner reads reflected light, converts the pattern into digits, validates it with a check digit, and looks up the product in a database.
First scan
A pack of Wrigley's gum was the first retail barcode scan in 1974.
Quiet zone required
Blank margins are necessary so scanners can identify the code boundaries.
Checksum digit
The final digit helps detect scan errors.
Not product data
Most barcodes store an ID number, not the price or description.
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