“The evidence of absence is not the absence of evidence.”
This adage of uncertain origins is something I heard often during my 20 years studying and working as an archaeologist. Most commonly attributed to Carl Sagan, the quote is variously interpreted, but generally thought of as pertaining to the definition of “scientific proof," or positive evidence of existence, and notions of truth. I find it interesting that the saying itself holds multiple meanings and is difficult to attribute to a particular origin, and more than a little ironic that, in and of itself, it is a dynamic thing that artfully evades exactness and thus elides truth, yet maintains verity in spite of its dubiousness. For these reasons, I found this quote a befitting title for this work.
In this project, I seek to distill photography into its essential nature – a recording of light. Through it, I also contemplate some of the many contradictions inherent in contemporary perceptions and uses of photography, namely the common expectation that a photograph is a picture of something – a discernable visage extracted from reality – and the medium’s long-standing capacity to simultaneously document fact and portray fiction.
The concept and form of this project are predicated, in part, on the cyanometer, a quasi-scientific apparatus invented in the late 18th century by a Swiss mountaineer and professor of natural philosophy named Horace-Bénédict de Saussure. An avid outdoorsman filled with the desire to measure the blueness of the sky, Saussure created a circular monochromatic scale of cyan using Prussian blue pigment applied to white paper. The oculus-like instrument was simply held to the sky as a qualitative reference for ascertaining its hue. Saussure theorized that the blueness of the sky was an optical effect that changed in relation to moisture content, but precise measurements of these phenomena could not be attained with his device. Subsequent scientists surmised that the perceived blueness of the sky is an effect of light scattering in the atmosphere. Although it was largely subjective, Saussure’s simple device is similar to the Munsell color chart used today for describing soils by archaeologists and geologists.
Prussian blue is a traditional pigment formulated in the 19th century with iron. The same principal chemical constituent (potassium ferricyanide) later provided the basis for the UV light-sensitive photographic process called cyanotype, invented by Sir John Frederick William Herschel in 1842, nearly 100 years after Saussure’s cyanometer. Like Saussure, Herschel was interested in observing and recording the heavens. In fact, both he and his father, Frederick William Herschel, were renown astronomers whose notable discoveries along with innovations in optics, chemistry, and photography contributed greatly to science and forever altered the course of history.
I create the images in this series using a two-part photographic process that records the quality of light in the sky the day before, and then again for the duration of, six selected solar events that occurred over the course of a year. The selected solar events are: Perihelion, Vernal Equinox, Summer Solstice, Aphelion, Autumnal Equinox, and Winter Solstice. While photographs are often associated with capturing a precise, fleeting instant, this project instead repeatedly layers several moments and folds them into a greater duration of time.
I imposed a set of arbitrary constraints on my process of making the photographs as a proxy for the scientific method and a means to recreate the gradation of tones in the cyanometer. While adhered to rigorously, the precision of the constraints does not substitute for actual science, even though the photographs are, in fact, two-fold physical recordings of actual events. Therein lie two enduring contradictions of all photography, its inherent ability to create fictitious truths and the notion that what you don't see in a picture is often as significant as what is included in the frame.