Hamerton noted in an 1867 piece critiquing Whistler's Symphony in White, No. 3 that the painting was "not precisely a symphony in white", since yellow, brown, blue, red and green were also used. Whistler's witty retort was that Hamerton must believe "that a symphony in F contains no other note, but . . . a continued repetition of F, F, F". Hamerton's conservative aesthetics emphasized technique as the major criterion in art appreciation. However, his writing on etching is considered, along with the work of Sir F. Seymour Haden (1818-1910), to have contributed to the revival of etching in American and Britain.