THE BRITISH LIBRARY

In through the outfield blog

14 December 2012

How the bar code was invented and developed

It has been announced that Norman Woodand, co-inventor of the bar code, has died. There is a BBC obituary with interesting facts about him and the invention. Bernard Silver, the other inventor, died in 1963. This post adds further information to the BBC story.

In 1948 Silver, a graduate student at the Drexel Institute in Philadelphia, overheard a conversation between a faculty member and a food store chain executive. The executive wanted the Institute to develop a system which would quickly and accurately capture product data at the check-out counter.

His friend Woodland first suggested ultraviolet light sensitive ink, but that did not work. Then he suggested adapting Morse Code – dots and dashes – by drawing them down to form thin and thick lines to represent binary information (zeroes and ones). The sand story, as told in the obituary (and new to me), came about when he was staying at his grandfather’s apartment in Florida.

Similarly the DeForest movie sound system, that used a sensitive tube to detect the projector light shining through the side of the film, was adapted. Light was converted into numbers rather than into sound. The patent advocates a shape like an archery target rather than our modern linear design, so that it could be scanned from any direction (both covered both formats). Its title was Classifying apparatus and method and it was filed for in 1949. Below is the main drawing.

Original bar code patent drawing

The concept was not feasible until computer power and cheap reliable machines based on lasers became available in the late 1960s. The now standard bar appearance is used, as the target design meant that the ink tended to “bleed”, making accurate reading difficult. The common usage of uniform barcodes had to be agreed by manufacturers in what is now the Universal Product Code, or UPC, and must have been a huge effort, as lots of items had to have codes printed on them before any scanning actually happened.

A bar of Wrigley’s® chewing gum was the first to be scanned, in an Ohio store in 1974.

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