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Where Did the Mirrored Bars for the Barcode Symbol on Aluminum Cans Come From?

After the announcement of the IBM 3660 U.P.C. Barcode Scanning System on October 11, 1973 and through 1974 one of my responsibilities was to encourage the Source Marking of the symbol. One of several activities to accomplish this was a series of Seminars for Grocery Manufacturers, and people in the Printing and Packaging industries designed to reduce the fear of problems with the tightly prescribed definitions for the edges of bars, etc. At the same time we could point out other significant parts of the complete Symbol Specification that might not be getting the attention it needed. These seminars were very popular. Our briefing room which might handle 6 to 12 people for a Grocery Retailer briefing would be reconfigured classroom style and used to handle 30 - 40 Manufacturer Packaging related attendees.

One of the specification parts sometimes overlooked was the color guidance near the back of the book. Grocery scanners being Helium-Neon lasers were red light. Users were counseled to view symbols under a Kodak Wratten #26 filter. We had been shown red bars on a white milk carton and black bars on a green package of gum. Red on white will look all white and black on green looks all black in red light.

I had completed a set of illustrations that showed laser spot sizes, depth of field, and barcode decode methods to demonstrate it was hard to make a tolerance error. Then I pointed out the color requirement. There was a ripple of quiet comment while the attendees realized they hadn't noticed this before. And then a voice in the second row and just to the left of me stated: "Coca-Cola's colors are red and white." The word Coca-Cola stopped me cold and I quickly tried to assure the person that it was just physics. IBM and the industry were not conspiring against Coca-Cola. He restated that "Coca-Cola's colors are red and white." I asserted that this was really caused by Physics, it was Mother Nature. He restated that: "Coca-Cola's colors are red and white."

I finally gave up and got it. Instead of going with the attendees when they tried to scan their test packages, I went up the hall and found the Joe Woodland. Joe promised to look into it and found the scanner engineers. About 2:30 that afternoon, Joe Woodland came back and explained to the group that if they left the dark bars unpainted, the shinny surface would cause the laser bean to stay very coherent and bounce off somewhere the light collectors would not see it. That would make it appear to be black. I suspect Lee Dixon came up with this but I don't know for certain, but it worked.

--Bill Selmeier