The Pencil of Nature: Tracing Intertidal Media through the Development of Early Photography

This paper considers the role of macroalgae (seaweed) in the mid-19c Daguerreotype process and subsequent technical developments in chemical photography. Since antiquity, seaweed has been used as an important supplement to human well-being. Ancient medical literature recommends burnt seaweeds for the treatment of endemic goiter. Centuries later, in the mid-19th century, iodine extracted from kelp was elevated as a medical panacea. Seaweed, and the iodine it produces also has a history in the technical production of images; during the same period, the modern photographic image was born from these briny plants. In 1839 Louis Daguerre used iodine to photosensitize the earliest photographic plates, bringing into focus “the pencil of nature” (a phrase that early adopters of the Daguerreotype process used to describe their invention’s descriptive potency). This notable aspect of human technological development draws the molecular activity of the hydrosphere and complex organic organisms like macroalgae into visual culture. Its traces reveal the commonality of oceanic mediations in natural, technical, and human processes.