"Truth to Nature," a rallying cry for those artists and critics aiming to reform art-making practices in Great Britain over the course of the nineteenth century, bound together artists as diverse as Pre-Raphaelite John Everett Millais, photographer P. H. Emerson, and bohemian modernist Augustus John. In order to understand "truth," these artists turned to the rising disciplines of science, which offered new insights into physical phenomena, vision,...