45th Annual Meeting – Photographic Materials Session, May 31, “Uncovering Irving Penn’s Chemical Treatment Techniques” by Laura Panadero

In this talk, Laura Panadero detailed the research she conducted in order to learn more about the chemical treatments performed on Irving Penn’s Nudes series. Shot and printed by Penn between 1949-50, the Nudes series depicts over one hundred images of female nudes that more recently, have garnered increased visibility. For example, they were exhibited in a solo show, entitled, Earthly Bodies: Irving Penn’s Nudes, 1949-50, in 2002, and are currently on display in the extensive retrospective, the Irving Penn: Centennial, at the Metropolitan Museum of Art. The Nudes have long since been a topic of interest as the body shapes in this series deviates heavily from those of the models whom Penn frequently photographed for Vogue. However, Laura was most interested in the visual differences between the nudes and the fashion works that Penn produced and decided for this exploration to be the focus of her thesis project for her studies at NYU’s Institute of Fine Arts Conservation Center, from which she graduated this May.

Since there were no notes written by Penn explaining his process for the Nudes, Laura consulted two documents for her research. In an early interview with Maria Morris Hambourg, Irving Penn attributes the visual distinctness of his Nudes series from his other photographs to chemical treatment. Laura also conducted her own interview with Robert Fresón, the man who worked with Penn to print the Nudes, to gather information about the process. The goals of Laura’s research included finding evidence for chemical treatment on the photographs, uncovering the techniques of the treatment, and understanding the significance of the treatment as it related to the series’ concept and materiality, as well as to Penn’s work as an artist.

Laura began by addressing the visual evidence for chemical treatment that she saw on the Nudes. First, they consist of a split tonality, in which the minimum density and mid density areas exhibit a pink or orange tone, whereas the maximum density and shadow regions had more of a neutral or cool tone. Secondly, the photographic image displayed a mottled or uneven effect at the edges of the model’s body, which, when compared with the crisp and clean negative, hinted at some alterations at the printing stage. Thirdly, there were variations between different versions of the same image, including variations in density.

The darkroom experiments that Laura performed were crucial to her process and research. In the interview with Penn that Hambourg wrote about, Penn described that his prints were affected by a bleach and redevelopment treatment. This process involved taking your developed photograph, bleaching out the metallic silver so that it oxidized into colorless silver salts, and then redeveloping the print a second time. Both Irving Penn and Robert Fresón attest to a bleach and redevelopment treatment, explaining that Penn began with a slightly overdeveloped print, and then used the chemical process to work with the excess image density and give the prints their mottled effects. However, Penn described the bleaching agents as potassium ferrocyanide and potassium permanganate solutions, while Fresón described it as potassium dichromate.

Laura replicated the two methods to see which produced images more closely resembling those of Penn. She did these experiments at the Metropolitan Museum of Art in the Department of Photograph Conservation’s darkroom and produced interesting results. She found that when using the method described by Fresón, the print had lost density in the maximum density areas and it produced a softly mottled appearance, similar to that of the Nudes, and that the potassium dichromate bleaching agent was more likely to be the one that Penn used when bleaching his prints to achieve the desired aesthetic look. The potassium ferrocyanide and potassium permanganate solutions, she found, intentionally disproportionally affected the maximum density areas and contrastingly, in the Nudes, the maximum density areas seem to be the least affected by the chemical treatment.

XRF analysis was done on the Nudes and on Laura’s samples by Andrea Schlather, Scientific Research Fellow at the Met, and it was found that the XRF detected traces of chromium in the samples that were treated with the potassium dichromate bleach. However, there was no chromium or non-silver material detected in the Nudes themselves; XRF indicated only silver particles over a baryta layer. Does this suggest that the visual congruity between Fresón’s process and the experiments performed by Laura on the samples is just a coincidence? Laura wondered if the chromium could be washed away from the sample to only keep the silver salts, but this question was not part of the active experimentation. She also pointed out that the XRF analysis couldn’t tell us anything more than the elemental composition of the silver gelatin print, and couldn’t give any information about the change in quantity or oxidation state of the silver, so this is important to note for future monitoring.

She recognizes that there are factors that could not have been accounted for, such as the paper Penn was using, nor the developing chemistry, and that the printers may have been contaminating bleach baths, or otherwise mixing chemistry during the process in a way that would alter the effects. Although the project has not returned any definitive results, the research is ongoing and Laura would like to conduct more tests and also employ analysis such as color measurements for continual monitoring. Ultimately, Laura’s talk is a reminder that investigating an artist’s process is crucial to understanding his or her workflow and thought process. She concluded that from the interview and from scholarly research, it was evident that Irving Penn was very interested in the materiality and darkroom processing of the photograph and this interest has clearly and physically manifested in a set of beautiful and unique photographs.