DAR ES SALAAM, July 17 -- PERMIT me to begin with a confession, because every respectable Friday read should start with somebody admitting something mildly embarrassing before advising the nation. I belong to the generation that believes most photographic problems can be solved by searching a camera bag.

Beneath a dead battery, three mysterious cables, a receipt from a shop that closed in 1998 and a lens cap last seen during the Mkapa administration, there must be an answer. There may also be a boiled sweet of uncertain age, but eating it would require approval from a doctor and the National Archives.

For much of my professional life, a missing photograph meant travelling to find it, befriending an archivist or waiting until Monday. The...