Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/LEON_a_01264 by guest on 27 September 2021 artist’s note Refractive Fingerprints of Lenses Explorations in Light Transformations
S h e i l a P i n k e l
Searching for an apt visual metaphor for multiculturalism to form Early lenses prior to the use of lens coatings refracted light CT the cover of an exhibition catalogue in 2011, the author scanned A in colors similar to prismatic light refraction. I was especially a Canon lens using a flatbed scanner and found that the whole interested in the potential of the scans to reveal the struc-
BSTR visible color spectrum was included in the resulting image. This A serendipitous discovery led to an ongoing research project on ture of the lens components. Thus, when possible, I scanned the unique refractions of all manner of lenses. them in both their wide-open and stopped-down aperture settings [1]. The configuration of lens elements [2] in front of or behind the aperture determines whether there is a great During the fall of 2011 I discovered that when I scan lenses difference or little difference between the two scans (Color on a flatbed digital scanner, each lens has its own refractive Plate A). “fingerprint.” I became fascinated by the remarkable differ- In order to provide some background for my current work, ences between the refractions of various lenses. Since then I should say that in 1979, I read the book Goethe’s Color Theory I have scanned lenses from the California Museum of Pho- [3]. I was intrigued by the possibilities of making visible color tography archive, the Canon Corporation office in Los Ange- when black, grey and white two- or three-dimensional art- les, Freestyle Photographic in Los Angeles, George Eastman works, sculpture or installation were viewed through a prism. House, Bausch + Lomb, the University of Rochester, and The high-contrast black-and-white graphics in Goethe’s book camera stores and private collections throughout Southern became colorful when viewed through a prism, indicating California. that the brain can “see” colors that it cannot see without the To scan the lenses I originally used a Microtek Scan Maker aid of a prism. I became fascinated by the possibility of the 9800XL flatbed digital scanner. I tried a number of other addition of color based on whatever viewing device is used. scanners but found that this one gave me the greatest resolu- My interest in Goethe’s ideas was from my vantage point as tion. Recently I also started using a Canon 9000F Mark II an artist rather than that of a scientist. I was and am not inter- digital scanner, which has even higher resolution. To scan ested in the mathematical veracity of Goethe’s work. Instead, the lenses, I have to make sure that the lens is placed in the I was fascinated by the transformative potential of a prism to horizontal center of the glass platen with a black cloth over make color visible in an otherwise black-and-white artwork, the lens to cut out random light noise. The configuration of which the plates in Goethe’s Color Theory demonstrated. In the final image is determined by the structure of the lens in all my artworks throughout my life I have tried to make vis- combination with the structure of the exposing system of the ible the invisible in nature and in culture. The transformative scanner, in this case a horizontal light bar that moves from potential of the prism to add color to high-contrast images top to bottom below the glass plate. was in keeping with my larger artistic direction. In 2015 I I found striking differences between the refractions of revisited this prismatic investigation and continue to make mid-nineteenth-century lenses used on the earliest cameras graphics that explore prismatic light mixing. and lenses subsequently developed in the twentieth century. The ideas of George Kubler, author of The Shape of Time, are relevant here. In this book Kubler distinguishes between
Sheila Pinkel (artist, educator), 210 N. Avenue 66, Los Angeles, CA 90042, U.S.A. the biological model and electrodynamic model of history. Email:
©2018 ISAST doi:10.1162/LEON_a_01264 LEONARDO, Vol. 51, No. 2, pp. 118–123, 2018 119
Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/LEON_a_01264 by guest on 27 September 2021 as it enlivens the minds of people at a particular historic mo- shadows turned into brilliant color when viewed through the ment. When minds no longer find that idea useful, it goes large prism placed in front of the installation. dormant. However, when minds later in history are enlivened When making “Goethe Gardens,” I also experimented by it, that idea reemerges as long as it is useful. In my case, I with polarizing filters and cellophane film with a molecular was fascinated by the transformative potential of light, and so structure in the shape of columns because of the color trans- when I saw colors emerge through the prism while looking formation of a black, grey and white sculpture that occurs at Goethe’s plates, I became quite excited by the possibility when viewed through polarizing film viewer. When I place of forming color in the mind that is not on the page. I began cellophane film throughout sculptural monochromatic in- to explore two and three-dimensional possibilities for trans- stallations and view them through a spinnable polarizing film forming monochromatic works into brightly colored works wheel, very colorful interference patterns become visible. In in which the color continuously morphs and intensifies in a 1985 version of the “Goethe Garden” installation, viewers the mind’s experience. saw first the monochromatic work and then its transforma- In the period 1980–1989, I made several “Goethe Gardens,” tion through the prism and a second transformation through consisting of black, gray and white sculptural installations polarizing film, allowing them to personally experience the with strong directional light so that shadows were cast on the dynamic nonstatic color possibilities of the work and trans- floor and walls as well as the sculptural elements. Wherever formative potential of light as experienced by the mind. an edge appeared, colors of red, yellow and blue were visible This brings me to my current work on lens scans, where when the installations and 2D artworks were viewed through I was surprised to once again encounter Goethe’s prismatic a prism. When two edges are close together, light mixing oc- phenomena. Early lenses reveal refractive light bending at the curs, adding secondary colors as well. When viewed longer edges of each lens element similar to prismatic bending of than 15 seconds, colors seem to intensify in the mind’s eye. light in Goethe’s high-contrast drawings. These early lenses In Fig. 1, an installation done at Pomona College in 1989, a (Fig. 2) were composed of relatively simple combinations one-point bright light source on the floor was positioned of glass lens elements made from crown glass or flint glass. to maximize shadows of the forms on the walls. A quote by As scientists continued to better understand the subtleties Goethe, “Everything that lives strives for color,” was visible in of light transmission and amplification, they were able to white letters on the floor. The edges of the letters, forms and combine lens elements with greater precision. After World
Fig. 1. “Goethe Garden,” Pomona College, 1989. This installation view was not taken through the prism. (© Sheila Pinkel)
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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/LEON_a_01264 by guest on 27 September 2021 Later in the twentieth century, refractive coatings for lens surfaces were developed to enhance their light transmission ability. A major problem for lens manufacturers is light re- flection, which reduces the intensity of light transmission by 4–8% at each glass-air interface. Thus, as the number of lens elements increases, light transmission decreases. By 1935, Zeiss had perfected a single coat deposition of a very thin layer of magnesium or calcium fluoride to improve light transmission [4]). This coating allowed the transmission of very precise wavelengths of light. Scans of these lenses reveal the structure of the lens elements in combination with the coating on the lenses, which in most instances reveal an in- tensity of color normally not seen. Alma Zook, a physics professor at Pomona College, re- cently told me that her father had been given the challenge during World War II to develop lens coatings for periscope prisms to enable more transmission of light so that navy per- sonnel could better see enemy submarines at dawn and dusk. Fig. 2. Scan of Lerebours Daguerreian camera lens (1850), 2013. In this case the lens coating reduced reflections of light from (© Sheila Pinkel) the prism, enhancing transmission of light. After World War II, multiple coatings were perfected by Asahi Optical Com- pany, Ltd., and then other lens manufacturers, enabling the design of complex lenses with many lens elements. Recent conversations with physicists at Pomona College, Harvey Mudd College and the University of Rochester have helped me understand the language of refraction that was unfolding. For instance, one physicist hypothesized that when two adjacent lens components have slightly different curvatures, interference patterns result, appearing as alter- nating dark and light lines in the refraction, visible in the Leitz Wetzlar Noctilux lens scan (Color Plate A). Another physicist thought that these bands were the result of lens ele- ments being out of alignment. The oldest lenses I scanned date from 1840, when the lens elements were relatively simple. Among the lenses I scanned from the nineteenth century were multiple-lens cameras, like a Stereo Palmos camera whose twin Zeiss Tesar lenses, when scanned, look like eyes (Fig. 4) and nine lenses in a lens board used to take portraits in commercial nineteenth-century portrait studios (Fig. 5). The refractions from this setup are reminiscent of holography in that each image is formed from a slightly different vantage point. As lens manufacturers began to add coatings to the surface of the lenses to enhance light transmission, the refractions became much more colorful in most instances (Color Plate A). One physicist explained that because the color green is Fig. 3. Scan of Turner Reich Anastigmat circuit camera lens in the center of the human visual light spectrum, in more (first offered in 1896), 2013. (© Sheila Pinkel) efficient lenses the ultimate goal of the coatings is to transmit green and other colors near the center of the human visible War II they also began to use extra-high-refractive-index spectrum as fully as possible. Thus, the most efficient lens rare earth optical glass that resulted in even better clarity coating is one that delicately reflects in the pink/purple range and light transmission. and transmits green and most of the other light waves. Such The approaches to combining lens elements sometimes efficiency is demonstrated in a Zeiss lens on a Hasselblad included gluing them together, as was done in the Turner camera, with the subtlest refractions of the lenses I scanned. Reich lens manufactured in the early twentieth century (Fig. Most of the other lens coatings resulted in more colorful 3). Because the glue degraded over time, it became visible at scans indicating that more of the light was reflected than in the edges of the lens scan; this actually enhanced the beauty the more efficient lenses. of the scan. As I continued to scan, I began to recognize specific lens
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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/LEON_a_01264 by guest on 27 September 2021 Fig. 4. Scan of Stereo Palmos camera with Zeiss Tesar lenses (1909), 2013. (© Sheila Pinkel)
Fig. 5. Multiple lenses were used on large format cameras for portraits after 1860. Abraham Lincoln was the first U.S. presidential candidate to use the distribution of his photograph as a campaign tool. This kind of lens board could take nine photos of a person at a time, making it useful for mass distribution. (© Sheila Pinkel)
Fig. 6. Scan of Dallmeyer soft focus lens used by Man Ray, 2014. (© Sheila Pinkel)
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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/LEON_a_01264 by guest on 27 September 2021 manufacturers. The combination of optical structure and lens real time. Scans of the lenses sometimes include the camera coatings by a manufacturer began to emerge as a recogniz- itself. Details of the equipment and the color phenomena of able “fingerprint.” I inadvertently scanned the same model of refraction become “delicious” to look at for their own sake Canon lens in two collections. Both scans are identical, indi- when printed. cating that the refraction from identically structured lenses Recently, G. Ray Hawkins, a photography dealer and col- is the same. Scans of more recent lenses reveal very different lector of cameras used by preeminent photographers, al- structures than older lenses, reflecting new concepts in lens lowed me to scan lenses of world-famous photographers, construction. including Man Ray, Ansel Adams, Edward Curtis, Dmitri I made prints of these many lenses and discovered that Baltermants and Paul Outerbridge. The scans of lenses that when people look at them they talk about how the images produced seminal images in the history of photography add look like eyes or like planets (Article Frontispiece). I am another level of meaning to this project. Especially notewor- fascinated that people are able to find analogies that give thy is the Dallmeyer soft focus lens used by Man Ray, which the images meaning to them. Interestingly, the prints are is exceptionally beautiful (Fig. 6). The care with which early precisely clear where the lens front touches the glass surface lenses and their mounts were designed adds an aesthetic di- of the scanner and are slightly fuzzier in the area where light mension to this body of work. is coming through the lens and into the scanner. This is be- So far, I have scanned hundreds of lenses, including tele- cause the depth of field [5] of the optical scanning element scope and enlarger lenses. I still have a great deal to learn. In results in less clarity as the lens elements move away from a perfect world I would love to scan Louis-Jacques-Mande the scanning surface. This contrast between the physical lens Daguerre’s and Henry Fox Talbot’s lenses as well as the his- elements and light phenomenon in the final print is expe- tory of Leica, Zeiss, Canon and other manufacturers’ lenses. I rienced as the difference between the enduring presence of remain passionate about scanning lenses because I can never the lens housing itself and the temporal experience of light anticipate what will be revealed. coming through the lens, as if light is being transmitted in
References and Notes 4 History of Photographic Lens Design:
2 Lenses are built by combining lens elements: convex, biconvex, Manuscript received 8 October 2015. planoconvex, positive meniscus, negative meniscus, planoconcave, biconcave pieces of ground glass. The lens elements of the nine- teenth and early twentieth centuries were made from low refractive Sheila Pinkel is a professor emerita of art from Pomona crown glass and/or high refractive flint glass. After World War II light transmission was improved with the use of extra high refrac- College, where she taught from 1986 to 2011. Her work has tive index rare earth optical glass. See
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Scan of Leitz Wetzlar Noctilux 50mm, left view F 16, right view F 1.2, 2013. This was Leica’s first extremely low-light lens, designed in 1966. (© Sheila Pinkel) (See article in this issue by Sheila Pinkel.)
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