Mondo Knows Facts
Barcode scanners read light reflected from white spaces
Optical scanners detect reflected light between black lines rather than the black ink
Optical barcode readers do not actively process the black bars printed on packaging. Instead, the red laser light reflects off the bright white spaces between the dark lines. Sensor diodes detect the variable strength of reflected light to convert the pattern into binary signal data.
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Tags: barcodes, retail, technology
Barcode scanners read light reflected from white spaces: the short answers
- Where does this come from, and can I check it?
- Optical scanners detect reflected light between black lines rather than the black ink. The figure is taken from Smithsonian Institution, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
- Is this really a everyday life fact?
- Yes. It sits on the Everyday Life shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
- What else can I read about it?
- The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.