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How were Canaanite peoples using photochemistry by 1500 BCE?

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Underwater view of a glowing chain of tunicates with a scuba diver and boat visible near the water's surface in the background. — photochemical reaction Chain of fluorescent tunicates.

By 1500 BCE, Canaanite peoples were utilizing photochemistry through the production of Tyrian purple, a highly prized dye derived from the secretions of specific mollusks.1

The process involved extracting a puslike substance from a cyst located near the head of the mollusk. When this secretion was applied to textile materials and exposed to sunlight, a photochemical reaction occurred, causing the substance to develop into a permanent purple-red color. The primary chemical component responsible for this transformation is 6,6’-dibromoindigo.1

This industry was so central to the region's identity that the name "Canaan" itself may derive from an old Semitic word meaning "reddish purple," reflecting the significance of this dye or the textiles colored by it.2