In a 1968 photograph of Michael X, the self-styled British Black Power leader, being interviewed by the press in his London garden, a baby crawls in the right-hand corner, peeking through the journalists’ legs. The shot was taken by the child’s father, photographer and film-maker Horace Ové, who lived in the flat below Michael X. His son Zak Ové, now an artist aged 52, is the curator of a momentous show on black artistic achievement from the 1940s to the present. As the archive photograph intimates, his angle on history is a privileged, if unusual, one.