Plasmonics sheds light on the nanotechnology of daguerreotypes

Abstract

The capturing of images has become one of our most universal and commonplace technologies. As a digital electronic technology, it has permanently transformed society by revolutionizing personal recording and interpersonal communication. It has also revolutionized modern science, changing the way data are obtained and expanding our ability to study complex physical and biological processes. It is easy to forget that, in the recent past, the capturing of static and dynamic images involved time-consuming multistep chemical processes. The chemical recording of images begins with the preparation of a surface with photoactive chemicals that create regions of contrast upon exposure to light or, alternatively, realistic coloration patterns corresponding to the captured image, followed by additional chemical processing steps that would slow or altogether halt the photoactive chemistry, preserving the image as a relatively permanent record. The very first chemically captured images were demonstrated by Daguerre in the 1830s and dominated the first era of photography until more streamlined methods were developed (Fig. 1 A ). These first images have unique optical characteristics, including high resolution across their contrast range, a high sensitivity to viewing angle, and occasionally, subtle coloration. Because of the long exposure times required for capturing an image, the subject matter was frequently buildings or landscapes imaged under natural lighting, and many of these images show the surprisingly realistic coloration of a blue sky background. The subject matter of these earliest photographic images—daguerreotypes—have in many cases been permanently altered or even destroyed by natural and human events, making many of them invaluable historical records. Our understanding of the underlying physical and chemical processes that constitute these first images is essential for the development of effective preservation methods. Until now, however, the actual nanometer-scale physical … \n\n[↵][1]1Email: halas{at}rice.edu.\n\n [1]: #xref-corresp-1-1