Over 20 years ago I wrote about Giambattista Tiepolo in The Spectator. Shortly afterwards I went to visit Howard Hodgkin in his spacious, white, light-filled studio close to the British Museum. It turned out that he had read my column and was pleased that someone had been discussing this 18th-century Venetian, who was just his idea of what a painter should be: a subtle master of colour, poetic, sensual, a bit neglected — in other words, much as he saw himself.