The astronomer Sir John Frederick William Herschel was a lifelong friend of Julia Margaret Cameron. They met in 1835 in South Africa, where Cameron was recovering from an illness and Herschel was conducting astronomical investigations. Herschel was not only a preeminent astronomer but also made several significant discoveries in photographic processes, most notably the invention of the cyanotype blueprint.
Even before she began to make photographs, Cameron kept apprised of discoveries in photography through her correspondence with Herschel. In this portrait of her dear friend, Cameron sought to portray "faithfully the greatness of the inner as well as the features of the outer man." Cameron draped Herschel in a swath of dark cloth, which served to highlight his white hair and to focus attention on his face. Herschel's unruly hair and eyebrows and fiery eyes are features commonly ascribed to a popular image of "genius"; they effectively convey strength of character and intellectual intensity.