There exists an early photograph – a shadowy person, a stretch of wall – which dates from 1824: three years before Beethoven's death. It sets the mind racing with the thought that just such a primitive apparatus might well have been turned on Beethoven himself. Just as the early gramophone captured the last castrato, so a spectral image could well have existed of this extraordinary little man who even in his lifetime had become one of the great mythic figures of the civilisation of the West. Only a few years were to pass, and the next generation – Schumann, Berlioz, Chopin (beautifully, in that nakedly revealing tragic late photograph by Bisson) – are all recorded. Musicians, and many others: the heroic age of photography produced, in the hands of Nadar, startlingly immediate images of Baudelaire, which make him peculiarly our contemporary. Such images lend to the historical existence of those depicted something which all the documentation in the world cannot: this immediacy, this contemporaneity, this sense of Now. The invention of the camera created a great dividing line in our experience of the past.

Such thoughts arise when one gazes at the many existing photographs of Brahms. They put him in a different category to Beethoven, whom the passing of time has cut off from us, has reduced to a history-book figure. Brahms, by the aid of the camera, can be imagined as tenuously alive, as a real person to be seen walking about the streets of Vienna. The arguments for the greater truth of character portrayal achieved by the art of the portrait painter are still occasionally rehearsed and (more rarely) justified. It is also true that the typical nineteenth-century photograph is a posed one; whereas we esteem in a photograph a touch of the arbitrary, the fortuitous: the ‘snapshot’.