Colonoscopic tattooing: ready, steady, glow

Years before red–green colour blindness was defined in 5 per cent of the railway workers tested by Holmgren (following a train crash owing to misread traffic lights), Gladstone mused that Homer’s chromatic aberrances in the Iliad and Odyssey were due to a colour illiteracy at odds with the poet’s expansive vocabulary. Although this may have flattened the horizon of the philosopher–politician’s reading, chromatic limitations have more...