The coloured squares or rectangles discovered on the crimped finish of toothpaste tubes are the topic of a persistent city legend. This fable claims the colours point out the composition of the toothpaste, with every colour supposedly equivalent to totally different components: black for all chemical, pink for chemical and pure, blue for pure and medicinal, and inexperienced for all pure. This interpretation is demonstrably false and lacks any foundation in scientific or manufacturing actuality.
The marks serve a purely useful function within the manufacturing course of. These rectangles, sometimes called “eye marks” or “colour marks,” are learn by optical sensors throughout the filling, chopping, and sealing of the toothpaste tubes. The sensors detect the distinction between the mark and the tube’s background, making certain the equipment cuts and seals the tube on the right place. This automated course of depends on constant visible cues to take care of effectivity and accuracy in high-speed manufacturing traces. The colour of the mark is chosen to offer most distinction with the tube’s design, making certain dependable detection by the optical sensors.
