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Why was bleaching powder important to the paper and cotton textile industries?

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A labeled diagram of the chlorine element from the periodic table shows its atomic number 17, symbol Cl, electron configuration, and atomic weight range. The box is shaded green to indicate chlorine is a halogen, with icons for orthorhombic crystal structure, gas state at room temperature, and strong acidity. A key explains the icons and colors used. — chlorine Properties of chlorine.

Bleaching powder was essential to the paper and cotton textile industries because it provided a practical, effective way to whiten materials on a large scale. Before its introduction in 1799 by Charles Tennant, bleaching was a slow process that often relied on sunlight.12

While chlorine gas itself had been identified as a bleaching agent, it was difficult to handle and transport. Bleaching powder—a solid compound of chlorine and slaked lime—offered the same whitening effect as chlorine but was much easier to store, ship, and manage in industrial settings. Consequently, it became the standard bleaching agent for cloth and paper for over a century, remaining in widespread use until it was gradually replaced by liquid chlorine and other solutions in the 1920s.12