Throughout its early history, photography's authenticity was contested and challenged: how true a representation of reality can a photograph provide? Does the reproduction of a photograph affect its value as authentic or not? From a Photograph examines these questions in the light of the early scientific periodical press, exploring how the perceived veracity of a photograph, its use as scientific evidence and the technologies developed for printing it were intimately connected. Before photomechanical printing processes became widely used in the 1890s, scientific periodicals were unable to reproduce photographs and instead included these photographic images as engravings, with the label 'from a photograph'. Consequently, every image was mediated by a human interlocutor, introducing the potential for error and misinterpretation. Rather than 'reading' photographs in the context of where or how they were taken, this book emphasises the importance of understanding how photographs are reproduced. It explores and compares the value of photography as authentic proof in both popular and scientific publications during this period of significant technological developments and a growing readership. Three case studies investigate different uses of photography in print: using pigeons to transport microphotographs during the Franco-Prussian War; the debate surrounding the development of instantaneous photography; and finally the photographs taken of the Transit of Venus in 1874, unseen by the human eye but captured on camera and made accessible to the public through the periodical. Addressing a largely overlooked area of photographic history, From a Photograph makes an important contribution to this interdisciplinary research and will be of interest to historians of photography, print culture and science.