A pointing hand. A shaft of light through a tavern window. Five tax collectors at a table looking up. Caravaggio painted the founding scene of European Baroque in 1599, and every painter for the next forty years tried to figure out how.

Searching for Caravaggio's Narcissus? This is the painting: roughly 110 by 92 centimetres of oil on canvas, painted in Rome at the start of his career. A young man kneeling at a dark pool, looking at his own reflection. What the painting shows, why it is so dark, and how to bring the fine print home.

A young widow, a sword, a single light source. Reading Caravaggio's most uncomfortable masterpiece — the biblical story, the tenebrism, and why his Judith looks reluctant.