Abstract
This article examines the role of photography in the scientific discovery of cosmic radiation and antimatter, showing how a visual medium designed to react to photons was successfully coopted to detect invisible particles and antiparticles through traces left by their collision, so-called annihilation events. The continuous presence of cosmic radiation means that every photograph is always already a double image, carrying both a visible surface formed by photons and a latent image carrying traces of cosmic rays, the latter ‘image’ continuing in its perpetual state of ‘development’. It is the physical irregularity of the photograph exposed to the continuous and uniform shower of cosmic radiation that leads Doser to speculate on image formation not through an external referent but through the internal manipulation of the material substrate.