Reproducing Film Colors, and Their Significances


Barbara Flueckiger has run a series of projects to figure out how best to determine the original colors of films, throughout cinema history. She is developing means to more accurately replicate the colors in digital restorations. It’s a huge technical challenge: to understand not just the chemical and physical properties of film colors, but their origin in complex cultural predilections for certain color palettes. Her work promises to provide new shading to film interpretation and film history.


By Peter Monaghan




A 2014 state-of-the-art restoration of The Cabinet of Dr Caligari has been doing the rounds of art-house film venues, the result of work performed at L’Immagine Ritrovata, in Bologna, under the supervision of Anke Wilkening, of the Friedrich Wilhelm Murnau Foundation, in Wiesbaden. It’s a model collaborative project, and among those who worked on it was Barbara Flueckiger, whose applied research promises to be particularly important to the future of film appreciation and study.

Efforts had been made regularly since 1984 to restore Robert Wiene’s classic German silent film from 1919, which portrays an insane hypnotist who provokes a somnambulist to commit murders. Restorers had faced a quandary; it’s one that restorers always confront: How could they replicate the colors of the original?

That is far from a simple challenge.

Even when restoring black-and-white classics, technicians have to deal with color complications. Early films had visual qualities that depended not only on the lighting used during the filming, but also on what film technicians — directors, art directors, film processers… – did to the original camera negatives: how they tinted and toned them, or in some cases colored them by hand.

During the course of film history, explains Barbara Flueckiger, a professor of film studies at the University of Zurich since 2007, hundreds of cinematic color processes have emerged, many with roots in nineteenth-century still photography. But figuring out what those original colors and visual qualities were is no easy task. Yet, no comprehensive guide has existed to connect each color’s technical inputs to its contemporary reception and aesthetic and narrative uses. As Flueckiger says, “film color is an issue that few film viewers think about consciously even though the material of film and the nature of color information play a key role in how we perceive film.”



When assessing surviving prints of films, restorationists are faced with an often-baffling task of determining what the colors, tints, and tones of the original film were. A few, scattered prints of “Das Cabinet des Dr. Caligari” (“The Cabinet of Dr Caligari”), the 1919 German masterpiece by Robert Wiene, survive, including one held in Montevideo. Copyright: Friedrich-Wilhelm-Murnau-Stiftung, Wiesbaden. Photograph by Barbara Flueckiger. Source: Archivo Nacional de la Imagen – Sodre, Montevideo / Cineteca di Bologna.


In a recent article in The Moving Image journal — volume 15, issue 1 — Flueckiger, the author of two standard textbooks on sound design and visual effects and many scholarly articles, described the logistics of making the recent digital restoration of Caligari. She noted that while the film has been much analyzed over its near-century in existence, little has been written about the colors applied to the film.

Ironically, in fact, few film critics have seen those colors. That’s because when the first prints of the film, which were individually toned and tinted nitrate prints, were transferred to a more stable print medium — safety film — their toning and tinting were not copied over.

Color issues have come into – or been inappropriately left out of — some key critical discussion of Caligari. Take, for instance, Siegfried Kracauer contention in From Caligari to Hitler. There, Flueckiger notes, he argued that the film has “a fascist underpinning” that is conveyed by its expressionism. Flueckiger observes, however, that in making judgments that hinge in part on the film’s expressionist form of…well, expression, it would be wise to consider what originally went into the way the expressionism was expressed.

Of course, tinting and toning contributed significantly to that; yet “Caligari’s original colors have…been lost to generations of viewers,” Flueckiger wrote.

The efforts of the last decades demonstrate how tricky restoration has been. In 1984, the German Federal Film Archive restored Caligari with tinting and toning based on a nitrate print from Montevideo and a second copy from the British Film Institute that had original tinting, only. In 1995, the Cinémathèque Royale de Belgique used a Belgian print and applied color photochemically guided by a second, South American nitrate print. But the result, Flueckiger wrote, was then reduced to four dominant hues: daylight scenes were tinted in amber, night scenes in blue, private scenes in the female protagonist’s sitting room became a pale dusky pink, and so on.



Frames from one of six differently tinted and toned prints of the film “Das Cabinet des Dr. Caligari” by Robert Wiene (Germany, 1919) that survive from the 1920s. Copyright: Friedrich-Wilhelm-Murnau-Stiftung, Wiesbaden. Photograph by Barbara Flueckiger. Source: Cinémathèque française, Paris.


In the 2014 reissue — the one that has been doing the festival and art-house rounds — film restorer/scholar Anke Wilkening of the Friedrich Wilhelm Murnau Foundation made a digital restoration based on a camera negative that had been newly discovered in the Federal Film Archive in Berlin but “for unknown reasons was never considered in earlier restorations,” Flueckiger wrote. The Wilkening project’s sophisticated, detailed “4K” output reflected maturing digital-restoration thinking and capabilities, and also went to great lengths to use the best parts of historical prints gathered from far and wide. Those included the six, differently tinted and toned prints that survive from the 1920s, and a 1919 black-and-white camera negative that was in good condition but was tarnished and incomplete.

Here is where Barbara Flueckiger came in.

Wilkening’s team took the prints and negative to L’Immagine Ritrovata, a film restoration laboratory in Bologna, and asked Flueckiger and the BFI’s Ulrich Ruedel to analyze the film’s colors. Wilkening wanted Flueckiger to analyze the colors not only for that restoration, but for any in the future.

flückiger U Zurich

Barbara Flueckiger. Photo: Anna Maltsev, University of Zurich.

Flueckiger had been working on such issues for years. In a succession of projects, she has combined research in film history, restoration practice, information technology, and aesthetics to figure out how to replicate, in restorations, the colors that films originally had.

The nature of her projects is worth repeating, here: She has been trying to figure out what the original colors were in films shot on many varieties of film stock, so that restorations can reproduce as closely as possible, in digital form, those original colors.

Raised in Switzerland, Flueckiger first worked in film production, mostly in sound engineering and design. She was doing well there; the work took her to about 30 productions around Europe and in the United States; however, she says by phone from Zurich, “I felt I needed to develop my intellectual skills a bit more and at the same time I became a mother.” Seeking a sane work life, in the early 1990s she returned to Switzerland and enrolled in film studies at the University of Zurich and the Freie Universität Berlin, back in Germany.

She found that her skills in technical aspects of film making lent themselves well to the abstract world of film theory. She wrote a 2001 dissertation about film sound design in American mainstream film, with financial support from the Swiss National Science Foundation. Her 520-page Sound Design: Die virtuelle Klangwelt des Films, now in its fifth edition, is a standard text on the topic. She says: “That’s where I established the kind of thinking where I could reflect on aesthetics in terms of the underlying film technology and innovations.”

Working in film production, she had become well acquainted with the differences among film stocks, and with the capabilities of modern-day, high-definition “digital image acquisition,” and saw how that could permit her to lend fresh perspectives not only to film history and aesthetics, but also to restoration practice – the science of how, among other things, the distinctive “look” of various films is faithfully reproduced. “All the digital technologies were very familiar to me,” she says. Her “selling point,” she adds, has been that “I have a background in engineering, so now I’m trying to combine the two, with research in film colors.”


The film “Colour on the Thames” by Adrian Cornwell-Clyne (Great Britain, 1936) was shot in Gasparcolor, the most successful of several so-called chromolytic multilayer film processes that achieved brilliant, stable colors. Gasparcolor was named for its 1933 inventor, Béla Gaspar. Courtesy of BFI National Archive. Photograph by Barbara Flueckiger.


Reproducing the original “look” of a film can be a daunting challenge. It requires, first of all, understanding how color is captured in film or digital images. And that requires considerable knowledge of chemical and physical processes. Flueckiger has worked systematically towards a fuller understanding of what goes into the processes, and how that relates to such aesthetic considerations as what film looks like, and how the look affects perception and reception of film.

Filmmakers have long chosen carefully the variety of film stock they will use, knowing at least intuitively that that will have a bearing on their films’ qualities of expression. “Not so much directors, but cinematographers” have that sense, Flueckiger says. “They’ve had a lot of knowledge – maybe not so much about the physical foundations or the chemical ones, but they’ve had a lot of experience of, say, how a certain stock reacts to the situation on the set, the lighting, and the colors, and so on.” Cinematographers may, for example, have “a very specific sense of every minute detail, like what kind of hue a black should have; should it be green-ish, should it be blue-ish, how much should it be exposed or under-exposed, or pushed. They juggle all these aspects very consciously.“

“And of course there are also directors or set designers who have a very good sense of colors, in the sense of an aesthetic feeling or aesthetic sensibility for colors, and then they are able to establish a very conscious handling of the color schemes applied.”

Barbara Flueckiger’s projects on film color

In her 2000-2002 project Digital Cinema, she began to develop a scientific methodology for describing and discussing the interaction of film aesthetics and digital recreation of factors in it. As throughout her work, she enlisted an array of industrial and academic partners – in that first phase, those were from the University of Art and Design Zurich, Sony Overseas SA, Swiss Effects, the University of Basel, and the Swiss Federal Institute of Technology Lausanne, and others since have included the Swiss National Science Foundation and the Swiss Innovation Promotion Agency CTI.

She next ran, from 2004-2006, a research project on aesthetic and narrative effects gained from computer-generated visual effects in movies. She completed in 2007 a Free University Berlin postdoctoral thesis on visual effects in computer-generated imagery.



The complicated 1948 Pinchart process used four lenses to capture and then bring together images in red, green, blue, and grey scale. Illustration by Sarah Steinbacher, Multimedia & E-Learning-Services, University of Zurich. Source: “Colour Cinematography,” by Adrian Cornwell-Clyne (1951, Chapman & Hall).



Screen test in which Audrey Hepburn appears in 1952 as a draper’s shop assistant. It was shot with British Tricolour/Dufay-Chromex’s Dufaychrome film, devised in the UK by Jack Coote in 1943 and produced later in the decade. Courtesy of BFI National Archive. Photograph by Barbara Flueckiger.


All of that positioned her to investigate in earnest the aesthetic dimensions of technologies and technological innovations related to film.

In her 2008 to 2011 project AFRESA, on the digitization of archival film, she collaborated with industrial partners and the University of Basel’s Imaging and Media Lab. She was honing in on the best ways to understand, and harness, the chemical and physical properties of film and filmed or projected images. A major milestone, in that quest, was her Timeline of Historical Film Colors, where she and colleagues looked at how the digitization of archival films informs perceptions of film history. The Timeline was part of her Film History Re-mastered, begun in 2011; it investigated how perceptions of film history have shifted in the digital age. (An abstract and further information is on the university’s research database.) During the course of the project, she spent several months as a research fellow at Harvard University’s Department of Visual and Environmental Studies, working on historical film colors.

In an overlapping project, since mid-2012 Flueckiger has been considering how film processes affect audiences emotionally. She was co-leader of that project, which was run by the Department of Performing Arts and Film at the University of Art and Design in Zurich and the Department of Psychology at the University of Bern.



For his 1956 “Written on the Wind,” Douglas Sirk shot Robert Stack and Lauren Bacall in expensive Technicolor. Harvard Film Archive, item no. 3663. Photograph by Barbara Flueckiger.


Her DIASTOR Project at the University of Zurich, subtitled “Bridging the Gap Between Analog Film History and Digital Technology,” brought together several technicians and researchers – chemists, information-technology experts, film scholars, and related technicians from film labs, software and hardware companies, archives, and Disney Research Zurich — to develop systematic measurement approaches to film color. She and her colleagues have developed technological expertise on their target issues in collaboration with Swiss engineering companies, and they have combed through research in film history, restoration practice, information technology, and related fields.

DIASTOR’s objective was to analyze colors and figure out how to reproduce them accurately. She and colleagues showed that film scanners of that time were not the best tools for capturing faithfully the colors of early films. Among problems they detected were that scanners could not make accurate allowances for fading and other deterioration in prints’ images, and that modern scanners are calibrated to modern, common film colors, rather than those of early kinds of film stock. So, even scanning original negatives is problematic. Better results could be obtained by photographing the prints, and checking colors against physiochemical analyses.

All these projects are Flueckiger’s steps towards figuring out how to digitize color films accurately. That is a crucial element in modern film restoration projects, because those now almost always involve digitization.

The Timeline of Historical Film Colors has become a platform for Flueckiger’s broad linking of issues in film technology and aesthetics. It details the physical and chemical nature of film colors, how the colors have been used, and how they have been received. The tool starts from the prehistory of film colors, with details of technologies that predated moving images by several decades: early 19th-century experiments in color photography and contemporary theories of color perception.



Flueckiger’s Timeline of Historical Film Colors provides or links to a great deal of technical information, from many sources, about the many varieties of film stock whose properties she is analyzing, as in this cross section scheme of the 1955 Anscochrome film stock. From “Processing Anscochrome Motion-Picture Films for Industrial and Scientific Applications” by John L. Forrest, in “Journal SMPTE,” Vol. 64, Dec. 1955, p. 679.



An illustration of the layer structure of Gasparcolor film, from “Konzept zur Sicherung und Restaurierung von Gasparcolorfilmen am Beispiel von Radio Prohaska prophezeit,” a 2011 Bachelor Thesis by Andrea Krämer, HTW Berlin, Supervisor: Prof. Martin Koerber


The Timeline references many hundreds of books, technical papers, patents, and articles, and where possible, links to downloadable files of those. It includes thousands of photographs from historical film prints and negatives from archives around the world.

It is an awe-inspiring project, and has become an often-cited project in work relating to film color; one sign of its reception is that when it lacked funding in 2012, Flueckiger was able to keep it running through a crowd-funding campaign.

Step by step, Flueckiger is providing a freely accessible resource for restoration experts, film scholars, scientists, archivists, students, and a broader audience interested in film color and restoration. The latest phase, FilmColors: Bridging the Gap Between Technology and Aesthetics, commenced in September 2015 and is funded by a prestigious European Research Council Advanced Grant. The grants are designed to free up leading European researchers to pursue their work with few financial pressures. Flueckiger’s grant is allowing her to bring on board chemists and physicists equipped to measure color qualities with great accuracy. “I’m not familiar with those measurement methods and also with the interpretation of these measurement methods, but I am able to understand the results and also then to connect these results to the aesthetic outcomes,” Flueckiger says.



Thomascolor, a 1934 process invented by Richard Thomas. Illustration by Sarah Steinbacher, Multimedia & E-Learning-Services, University of Zurich. Source: Ryan, Roderick T. (1977): A History of Motion Picture Color Technology. London: Focal Press.


As she investigates systematically the connections among technologies, aesthetics, measured properties of film, and issues of digital restoration and preservation, “I’m trying to apply these experiments in a more systematic fashion onto a lot of film stocks, not just early film colors but also other analog film color systems,” she says.

Unpacking the properties and capabilities of film stocks used over the course of cinema history, and rendering all that into a form that can facilitate digital recreation, involves developing new software capable of analyzing many color films from each decade of film history.



An example of film shot in about 1920 in Prizma II, showing its two colors, visible at a splice. Credit: EYE Film Institute Amsterdam. Film: [Kleurenpracht]. Photograph by Barbara Flueckiger.


She and her team are also pushing ahead her earlier work on systematically investigating how technologies influence color perception and, in turn, aesthetics, which of course has cultural dimensions. “Technology is not transparent,” she notes. “Technology is evolving within a certain culture and it’s also generated within a certain culture… so by its very foundation there is already something like a bias towards a specific kind of rendition of nature, so to speak.”

To get at what those cultural inclinations have been, in the case of each kind of film stock, she pores over documentation of the tests that film companies made of the film stocks they produced. “There are a lot of papers explaining how they tried to achieve a certain look, and what their obstacles were,” she says.

a growing field of study

Flueckiger is not alone, of course, in taking account of color in classic films of the silent era, and later. She cites works likes Simon Brown, Sarah Street, and Liz I. Watkins’s Color and the Moving Image: History, Theory, Aesthetics, Archive (Routledge, 2013) and Moving Color: Early Film, Mass Culture, Modernism, by Joshua Yumibe (Rutgers University Press, 2012). And Giovanna Fossati, the head curator at EYE Filmmuseum and professor at the University of Amsterdam, includes the history of film materials in her analysis of early film. Flueckiger says she would like to connect the different perspectives: “I think we should add the colorometric analysis I do. But it is a very tricky thing because you have to have several different backgrounds, combined.” While, she says, “you find the technical papers, on the one hand, and you find the aesthetic criticism, or the traditional film-scholarship approach, on the other hand, there are rarely people who are able to combine these two perspectives and to figure out how they inform each other. So there are a lot of opportunities to investigate that.”

Of course, she adds, while film scholars might rarely investigate the chemical and physical processes of various film stock, and now digital image capture and processing, considerable thinking has gone into such issues in the laboratories of companies that have created the materials and processes. “I try to investigate the kind of thinking that went on, and also the kinds of material that evolved from that thinking, and then how in return the material informs the aesthetics of film productions.” So, for example, while working on a restoration of a film made on Agfacolor film stock from the 1930s, she has been reading the many research papers the company published on that film process. Scientists at the German Agfa company “did a lot of investigation about perception, and about nature, and about renditions of colors in particular environments,” says Flueckiger. So there was already all this reflection in the formation of the technology.” The dyes Agfa used have specific, distinctive characteristics, and those were in part determined by Agfa’s technicians’ aesthetic and cultural predilections. Flueckiger says: “You have to do a lot of research to understand the aesthetics of it, and then from there to figure out a way to reconstruct this specific Agfacolor look.”

In general terms – ones she and colleagues thought about while restoring Caligari — the task is to figure out “how these color schemes match specific aesthetics from the time; also, whether prints are decayed or are more or less stable; also, to compare all these diferent prints and to figure out where they came from.”

As she wrote in her paper in The Moving Image journal, the new restoration “shows that digital means allow for the much more complex integration of a variety of source elements into the final version,” particularly color. A key obstacle to restoring original colors, she wrote, “remains the interaction of the silver image with the tints and tones. Tinted and toned images are not merely black-and-white images enhanced by colors. They show a vivid and detailed palette of mid-range tones where more subtle interplays between chemical dyes and color compounds, the nitrate base, and the emulsion with the projection light occur.” And, analyzing those factors is a model for future restorations. One task in the DIASTOR project was to develop, with Disney Research, a tool called RestoGUI for transferring the color values from a reference image into the digital domain, and then onto a target image.



In the color and style transfer facilitated by the RestoGUI tinting tool, which was developed at Disney Research Zurich, images from the raw scan (top left in each of these four-cell arrays) are adjusted semi-automatically to a color reference (top right, in each array), “difference image” (bottom left), and adjusted image (bottom right). RestoGUI tool developed by Simone Croci, Tunç Aydin, Aljoscha Smolic, Disney Research Zurich / Swiss Federal Institute of Technology Zurich.



Says Flueckiger: “This tool works quite well, now, but I would still try to improve some of the aspects of it. But basically it’s a great tool. It’s much easier to do the color grading based on this semi-automatic tool than to do it all by guess work.” She explains: “You know how you have captured it, and you make every decision transparent. You don’t have to rely so much on five people who are looking at a core sample and one says this yellow is a little bit darker, and another says no it’s a bit more orange. Instead you can capture the color values directly from the color reference which is already in the digital domain, and then you can just put it with a split screen next to each other and see whether they match, or whether they don’t.”


the shock of early cinema



Tinting and toning in “Venus of the South Seas” (1924), performed with the Prizma II process, developed by William van Doren Kelley between 1919 and 1923, a successor to his earlier Prizma I, of 1913. Library of Congress. Photograph by Barbara Flueckiger.


Anyone who has attended screenings of early film is likely to have been struck by some visual aspects that have come to seem characteristic – not just halting human movement, but a scratchy, dim, somewhat tattered visual field. But of course, audiences in the giant movie palaces of 100 years ago would have seen something quite different – they’d have seen what audiences today see when they attend screenings of the highest-quality restorations of early films, such as the one executed at L’Immagine Ritrovata and associated technicians make of Cabinet of Dr Caligari with input from Barbara Flueckiger’s color analyses.

Seeing films as early audiences would have seen them provides a powerful visual surprise. You are unlikely to think about that the way Flueckiger does. She considers about, among other things, the kinds of illumination used in early projectors, such as carbon arc illumination, and what kinds of spectral power distribution it produced; what the properties of screens were, at particularly times in film history; and so much else that can contribute to a peak viewing experience. Of course, Flueckiger says, it’s impossible to replicate the past, precisely. What is possible, however, is increasingly becoming apparent. It’s the answer, imperfect but improving, to her question: “What were the conditions and how much of these conditions can you take into account for your restoration project?”


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