Calotypes Research and Exhibition

British inventor William Henry Fox Talbot created the “calotype” (also referred to as the Talbotype) in England in 1840 stemming from his work with “photogenic drawing.” Photogenic drawings were created by placing objects on paper sensitized with a mix of chemicals, exposing the sheet to light, then stabilizing the image with sodium chloride or fixing with sodium thiosulphate. There was no use of a camera in that process and it yielded only a single copy. Calotypes, on the other hand, used chemically sensitized paper that was exposed in-camera, creating a paper negative which an artist could use to make multiple prints. The calotype was introduced to the public in 1841 but was already largely replaced by glass negatives by the 1850s.

In 2015, Getty acquired 23 prints and 16 paper negatives from 21 artists, created between the 1840s to 1860s. Among the acquisitions were two pairs of paper negatives along with their positive prints. Some notable artists represented in this acquisition include French pioneers of the medium such as Charles Nègre, Gustave Le Gray, Bisson Frères, and Henri Le Sec. This acquisition was the catalyst for the studies and subsequent exhibition of early paper negatives at Getty.

The idea for the calotype project grew from conversations between Getty and several French cultural institutions. Getty photographs curator Karen Hellman and paper conservator Sarah Freeman met with Sylvie Aubenas, Chief Curator of the Department of Prints and Photographs at the Bibliotheque Nationale de France, Anne de Mondenard, and Paul-Louis Roubert about the forthcoming Getty exhibition and publication Real/Ideal: Photography in France 1847–1860. Their discussions led to the Calotype Initiative Project spearheaded by de Mondenard (Centre de Recherche et de restauration des musées de France) and Bertrand Lavédrine (Centre de recherche sur la conservation). Shortly after, Art Kaplan of the GCI joined the project.

Basic measurements of each calotype acquired by Getty were taken to document size and thickness of the paper, and to better understand which plate holders were used in production. Various methods of testing (described below under Methodology), were utilized to document material composition.

To gain a better understanding and help with the interpretation of the analytical results, a series of standards were prepared using a variety of coating materials and following historical recipes. One series of un-aged standards was analyzed using Fourier-transform infrared spectroscopy (FTIR) while another set was artificially aged and analyzed. The results of the analysis of the standards were compared to the analysis of the historical images in order to help identify the material present as well as to make a comparison between the naturally aged historic samples and the aged and unaged standards.

The light sensitivity of each negative was measured using a microfade tester (MFT), analyzing areas of different densities on each negative and using a blue wool reference standard. Elemental analysis of each negative was performed using X-ray fluorescence (XRF) spectroscopy in order to identify paper fillers, imaging metals, and any possible toning metals. Areas where there was evidence of applied pigment or other material to the surface of any negative were also analyzed using XRF. In order to identify the presence of any sizing or organic coating, FTIR was used. The FTIR analysis was performed using both reflectance and attenuated total reflectance (ATR) techniques on multiple spots of the recto and verso of each negative.

In developing Real/Ideal: Photography in France, 1847–1860, an exhibition about four photographers in the Getty collection – Gustave Le Gray, Henri Le Secq, Charles Nègre, and Édouard Baldus – curators wanted to emphasize the role of the paper negative in this period and how each photographer uniquely utilized the process.

A close collaboration between curator and conservator, along with expertise from specialized staff, led to the development of a dedicated gallery within the exhibition on the positive/negative process. Calotypes and matching positives were displayed with customized mounts and lighting designed to highlight the double-sided nature of the negative and its unique qualities. Visitors were given a rare opportunity to appreciate and understand the multifaceted qualities—aesthetic and technical—of the paper negative.

Getty Conservation Institute
Centre de recherche sur la conservation (CRCC)
Centre de Recherche et de restauration des musées de France (C2RMF)
Bibliothèque nationale de France (BNF)
supported by Patrima Foundation (2016-2017)