'The surface of a photograph can be matt or glossy, but it is always flat. The illusion of threedimensionality that it offers is based on the uninterrupted expansion of a flat surface, which, unlike a painting, does not draw attention to itself.’
- Graham Clarke
The Silver Salts series explores the expressive potential of the photographic medium through a thorough investigation of its most basic elements: light, chemicals, and substrate. By reducing the medium to these components, the restrictions and obligations that photographic representation traditionally carries are eliminated. Without a camera, a negative, or the obligation to represent the material world through a lens, the photographer is able to understand the very essence of the medium and allow the surface of the photograph, once invisible, to become the subject of the work.
In this series, Constanza Isaza Martínez draws upon research into the history of photography to produce a set of images using the salted paper process, one of the earliest photographic techniques for making positive prints on paper. The salted paper process was invented in the early nineteenth century by William Henry Fox Talbot, and designed to produce positive prints on paper from calotype negatives made in-camera.
The history of the invention of photography is populated by natural scientists, chemists, and astronomers, whose work required the precision of photographic representation, and therefore served as the catalyst for the invention of photography. Talbot himself conducted research in the areas of mathematics, optics, and chemistry before inventing the calotype and salted paper processes.
The Silver Salts series takes the salted paper process as a starting point and uses the chemistry and paper alone to make images without negatives or camera. The resultant images – which draw attention to the surface and nature of the photographic image – reference the chemical and scientific aspects of early photography and allude, through the shapes contained within their circular frames, to the process of investigation and analysis which is a fundamental part of both science and photography.
Using the chemistry itself to form the image, each photograph is a one-off positive print without a negative – the only ‘negative’ being the fragile chemical formations on the surface of the print, which are destroyed during processing.