Rembrandt’s portrait of his son Titus from 1655 is a special favourite of Jeroen Giltaij, curator of the old masters. Although the collection of Museum Boijmans van Beuningen has several portraits by Rembrandt, such as that of the Amsterdam lady Aletta Adriaensdochter (1639), he thinks that nothing compares to the portrait of Titus. Jeroen Giltaij explains what makes this painting so special.