Honary Doctor Lecture - Lippmann Photography: The Science and Art of Multispectral Images
Martin Vetterli is the current president of École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland were he is a professor. He will be promoted to Honorary Doctor of KTH on November 19, 2021.
About the talk: Gabriel Lippmann invented an original color photography process in the late 19th century, for which he obtained the Nobel Prize in Physics in 1908. Lausanne has a large collection of Lippmann plates at the “Musée de l’Elysée”. By coincidence, we came across this collection and we got totally fascinated by Lippmann photography! This led to a number of questions and sometimes surprising answers and applications that will be presented in the talk.
Tid: Fr 2021-11-19 kl 10.00 - 11.00
By pure serendipity and a chance encounter, we came across what is arguably the earliest example of multispectral photography, and the richest analog color photography ever created. Gabriel Lippmann invented an original color photography process in the late 19th century, for which he obtained the Nobel Prize in Physics in 1908 . The method relies on an interferential process, and as such, provides a recording of the entire color spectrum, rather than the trichromatic process common today. Because of complexity of the acquisition and the subtlety of the viewing process, Lippmann photography remains an all too rare curiosity.
Luckily, Lausanne has a large collection of Lippmann plates at the “Musée de l’Elysée” . By coincidence, we came across this collection while working on a high-resolution scanning project at the Museum, and we got totally fascinated by Lippmann photography! This led to a number of fascinating questions and sometimes surprising answers and applications.
First, can we produce a digital twin of a Lippmann photograph? This requires a high dimensional acquisition, which is possible thanks to technology from a spinoff of our lab, ArtMyn . Second, we needed to understand in depth the Lippmann process, from acquisition to rendering. This led to a precise modeling of the recording of the standing waves in the light sensitive medium, as well as of the rendering by white light exciting the recorded interference patterns. A physical model combined with mathematical analysis leads to a new and full understanding of the Lippmann process, which was verified by experimental acquisitions (with the help of Felipe Alves ) and imaging the resulting plates under X-ray imaging (CIME) and tomography (PSI). Some phenomena absent from previous analysis can be explained and verified with this new model. In particular, the folk theorem of perfect color reproduction was show to be just that, a folk theorem [5,6]. Third, we designed and implemented a “digital Lippmann camera” which mimics what the original, analog Lippmann photography acquires. This is an alternative to a multispectral camera, but based on interferometry. Interesting trade-offs between number of channels, pixels and exposition time can be explored . Forth, we consider Lippmann printing with femto-second lasers. The analog version being cumbersome, a digital twin would allow us to render original Lippmann photographs in full glory. Maybe more importantly, printing in three-dimensions and with a full spectrum could lead to a high density, permanent storage method, an approach we pursue with Y.Bellouard and his team . Last, our interaction with the museum holding the collection of Lippmann plates resulted in a common research project and exhibit for public communication of science, planned for Spring 2022.
In conclusion, a chance encounter with the powerful historical color acquisition of Lippmann led us to an exploration at the intersections of physics, applied mathematics, computer vision and computer graphics. Besides a fundamental understanding of the Lippmann process, it led to a digital version of a Lippmann camera, as well as exploring the feasibility for three-dimensional storage. I will finish with two tongue-in-cheek remarks, one about the publishing business , and the other about the blueness of the sky, in the 19th century, versus today.
Joint work with Gilles Baechler, Arnaud Latty, Michalina Pacholska, Paolo Prandoni and Adam Scholefield.
Felipe Alves: www.lippmannphotography.com/About-me Gilles Baechler, Arnaud Latty, Michalina Pacholska, Martin Vetterli, and Adam Scholefield, “Shedding light on 19th century spectra by analyzing Lippmann photography,“ PNAS, April 27, 2021, Vol. 118, No. 17, pp.
IEEE paper: working title, authors
Arnaud Latty et al, ‘’Digital Lippmann Camera’’, Tech. Report.
Y.Bellouard et al,
Nature, “A pioneering photographic method shows its true colors.” Research Highlights, 12.4.2021, p.491.