The growing internationalisation of African affairs from the late nineteenth century onwards was accompanied by an intensification of critical scrutiny of European colonial rule, both within Africa and beyond. "Civilised savagery" came under increasing examination, and the production, circulation, and strategic use of photographic images played a central role in this process. As both document and evidence, photography became a crucial means of "authenticating outrage" in response to imperial inequalities and colonial abuses, particularly those associated with new forms of slavery and coercive labour—often described as "modern slavery." Photography thus became a powerful political, social, economic, and "moral" instrument, mobilised by a wide range of actors for different, and sometimes competing, purposes.

In the early twentieth century, the plantations of São Tomé and Príncipe—and, in particular, the international controversy over "slave cocoa"—became one of the most revealing episodes in this broader history. This presentation examines how photographic evidence acquired such political and moral force, how it was produced and mobilised by different actors, and what the São Tomé controversy reveals about the relationship between visual politics, humanitarian critique, and the transformation of colonial governance.