Tabloid newspapers also theatricalized the common poor and made the gangster vivid. Riis presented his work directly to the public in lantern-slide shows, confronting his curious audiences with a world it could no longer ignore. The advent of the magnesium flash in 1887 enabled Riis to take photographs that brought an immediacy to his tales of the living conditions of the urban poor, although his subjects were often asleep, drunk, or too preoccupied or frightened to object to the photography. He was pivotal in changing the perception of the poor as idle, ignorant, and undeserving.

Jacob Riis was a social reformer and newspaper reporter who used photography to assist in the description of New York City slum conditions in his 1890 book How the Other Half Lives. But, as in these latter cases, it is not always evident at the moment a picture is taken what purpose it may ultimately be made to serve. The early twentieth-century portraits of Peruvian miners, the identification pictures of Algerian women, and the photographs of Cambodians held by the Khmer Rouge were also made ostensibly for reasons of identification. Identification photographs are on our driverвЂ™s licenses, our passports, and are often added to our bank cards to prevent misuse by an unauthorized signer.

The surveillance cameras that once were used primarily to identify the perpetrator in the act of a crime or to survey the potential вЂњcriminalвЂќ watch us as well. Now, surveillance cameras proliferate everywhere, from national borders to banks, from apartment-building lobbies to street-corner traffic lights. Surveillance was once restricted to wartime reconnaissance photography (such as Harold EdgertonвЂ™s pictures made in preparation for D-Day), or to tailing suspected spies during the cold war, or recording antiwar demonstrators in the 1960s and 1970s. The turn-of-the-century triumph of fingerprinting over BertillonвЂ™s anthropometric measurement system as the crucial method of determining unique physical characteristics has now given way to routine investigations into the genetic material that differentiates one human being from another. The chance existence of latent fingerprints on a murder victimвЂ™s palm is examined through chemical or microscopic analysis.

Evidence pictures are now made using a blinding array of technologies to capture minute and often unseen cluesa shoe print or the residue of a body once wrapped in a sack. With the twenty-first century almost upon us, the role of science in criminological investigations has never been more manifest. FBI photographs of this period focus on suspected informers, spies, and any others deemed to be interested in the destruction of the American way of life. The wide dissemination of such images was of great propaganda value to the government in its struggles with criminals.Д«y the mid-1940s, Hoover turned his attention to political radicalism, the incursion of the Left, and the threat of the cold war. Hoover countered the magnetism of such crime figures as вЂњPretty BoyвЂќ Floyd, Bonnie Parker and Clyde Barrow, John Dillinger, вЂњMachine GunвЂќ Kelly, and вЂњBaby FaceвЂќ Nelson with the sometimes graphic photographic images that the FBI used as evidence in court or provided to the press. Edgar Hoover unprecedented powers to fight the kidnappings, killings, crime bosses, and criminals that flourished at that time.

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