Abstract In the 1920s and 1930s, the French colonial phosphate mining company in Gafsa, Tunisia, used X-ray images to decide which of its workers’ injuries were fake and which were real. Through an analysis of X-ray photography in Gafsa, this article argues that a capacious history of capitalism—one connecting wage labor exploitation with other human and nonhuman work—requires methods that do not prioritize what is visible. Rather than asking what X-ray images show diagnostically, this article charts how the creation of visibility and invisibility was a political act, a tactic of capital accumulation, and an arena of contestation. Company administrators and doctors used X-rays to draw biomedical and temporal boundaries around chronic injuries, making them “nonexistent”—and thus noncompensable—despite workers’ claims. This colonial-racial project both reified and remade the company's semantic categories for defining what an injury was. The company mobilized the material and epistemological properties of X-ray light on a photographic negative to erase chronic injury within dark or blurred spaces. The resulting category, a “nonexistent incapacity,” acknowledged both the presence of injury and its disappearance, constructing visibility and invisibility within capitalist relations of production and exploitation. Read this way, Gafsa's X-ray images ultimately outline a political economy of (in)visibility.