A century ago, glow-in-the-dark watches were an irresistible novelty. The dials, covered in a special luminous paint, shone all the time and didn’t require charging in sunlight. It looked like magic.

A luminous watch, for those unfamiliar, has hands and indexes coated with paint that stores light, allowing the time to be read in darkness. A nighttime saviour for adventurers and soldiers alike, ...