Sergio Benedetti: a keen researcher, he was professionally very focused and demanding, and expected high standards from those around him. Photograph: National Gallery of Ireland

One August morning in 1990, Sergio Benedetti, who has died aged 75, walked the short distance from the National Gallery of Ireland, where he was a con(...)

 The Taking of Christ (cropped) by Michelangelo Merisi da Caravaggio, oil on canvas. Photograph: National Gallery of Ireland

In his time, Michelangelo Merisi da Caravaggio (1571-1610) was the most conspicuous example of a new kind of artist, one that has become familiar as a(...)