The Hockney–Falco thesis is a controversial theory of art history that argues that advances in naturalism and accuracy in Western art since the early Renaissance were due primarily to optical aids such as the camera obscura, camera lucida, and curved mirrors, and that the use of these aids was more widespread than previously believed. The theory was proposed by artist David Hockney in 1999 and further advanced with physicist Charles M. Falco since 2000 (together as well as individually).
In his 2001 book, Secret Knowledge: Rediscovering the Lost Techniques of the Old Masters, Hockney more extensively analyzed the work of the Old Masters and argued that the level of accuracy represented in their work is impossible to create by "eyeballing it". It formed the basis for the 2002 BBC documentary David Hockney: Secret Knowledge, with some new ideas and experiments that in turn inspired additions to the second edition of the book (2006).
Nineteenth-century artists' use of photography had been well documented, and many art historians had already suggested that certain artists had used the camera obscura for their work (most notably 18th century painter Canaletto and 17th century painter Johannes Vermeer), but Hockney believed that nobody had previously suggested that optics had been used as early and widely as he suggested. Many art historians contested the hypothesis, while others described the response to it as "publicity hype" and pointed towards earlier studies and writings.
Earlier incarnations The hypothesis that technology was used in the production of Renaissance Art was not much in dispute in early studies and literature.
In his treatise on perspective, early Baroque painter Cigoli (1559 – 1613) expressed his belief that a more likely explanation of the origin of painting lies in people conserving the image of the camera obscura by applying colours and tracing the contours of the projected figures, rather than Pliny the Elder's traditional story about a Corinthian tracing the shadow of the profile of her departing lover.
In 1755, Charles-Antoine Jombert noted that it was said that many of the Flemish painters (presumably the Flemish Primitives) had studied and imitated the effect of the camera obscura. Just like Hockney, he pointed out that the optical image differs from the way people see things naturally.
The 1929 Encyclopædia Britannica contained an extensive article on the camera obscura and cited Leon Battista Alberti as the first documented user of the device as early as 1437. However, Alberti's "device" was probably a kind of peep box, and the kind of optical devices that he and Filippo Brunelleschi used, have been explained as means to demonstrate the rediscovered and enhanced application of Euclidean geometric perspective rather than drawing aids.
Aaron Scharf's 1968 book Art and Photography details evidence of the use of photographs and the camera by painters. Scharf notes in his introduction that in 1568 Daniele Barbaro, the Venetian writer on architecture, recommended the camera obscura as an aid to artists: "By holding the paper steady you can trace the whole perspective outline with a pen, shade it, and delicately colour it from nature."
David Lindberg's A Catalogue of Medieval and Renaissance Optical Manuscripts (Pontifical Institute of Medieval Studies, 1974) lists 61 manuscripts written in the years 1000–1425. These manuscripts not only describe methods for making mirrors and parabolic mirrors but also discuss their use for image projection.
In 1990, Shigeru Tsuji argued that Brunelleschi had used the camera obscura to paint the panel for the famous experiment that has usually been heralded as the origin of linear perspective.
In 1994, Roberta Lapucci proposed that Caravaggio's well-known use of mirrors evolved into the use of the camera obscura to reproduce the whole figure of a model, rather than the details and parts that the mirror-technique was used for.
Origins of the thesis and early publications Aaron Scharf's Art and Photography is referred to by Hockney in his 1977 painting My Parents (Tate, London) in which his father is depicted attentively reading the volume.
As described in Secret Knowledge, in January 1999 during a visit to the National Gallery, London, Hockney was struck by the accuracy of the small portrait drawings by Jean Auguste Dominique Ingres, and by their resemblance to drawings by Andy Warhol that are known to have been traced from photographic images. He suspected that Ingres had used a camera lucida or similar device.
In June 1999, Hockney published in the Royal Academy magazine, speculating about Ingres using the camera lucida and Vincent van Gogh possibly using an epidiascope or other mechanical means for his painting of The Prisoners in the Courtyard, which very precisely reproduces Gustave Doré's engraving (although Hockney considered this could also be done with a squared-up copy). Hockney suggested that the relation between 19th century painting and photography had yet to be explored, and that the influence of the supposed veracity of photography was currently ending due to computer manipulation affecting the way people use and experience images.
Hockney began looking for signs of the use of optical aids in earlier paintings, creating what he called the Great Wall in his studio by organizing images of great naturalistic art by time period, which eventually seemed to display a sudden rise of naturalism around 1420. In March 2000, he showed the project to Charles Falco, a condensed matter physicist and an expert in optics. Falco became especially intrigued with Husband and Wife by Lorenzo Lotto (circa 1543), of which Hockney had enlarged a section of the pattern on the rug that seems to go out of focus. Falco suggested that the painting contained sufficient data to enable him to estimate the properties of the lens theorized to have been used for projection. He considered that such a calculation would provide the "smoking gun" of scientific evidence for the theory. Falco also noticed geometric pattern lines at the border of the rug that appear to imply different vanishing points, and he reasoned that this showed that, in addition to using a lens and projection to create this work, Lotto had refocused the lens when painting different sections of the carpet. (Hockney 2001, pp. 60, 254–257).
In July 2000, Falco and Hockney published "Optical Insights into Renaissance Art" in Optics & Photonics News, vol. 11, a detailed analysis of the likely use of concave mirrors in certain Renaissance paintings, particularly the Lotto painting. Experiments with a concave mirror (which technically is also a lens) of the calculated properties indeed produced a projected image that was bright and sharp enough to be of use to a painter. They also measured the distances between pupils in 12 examples of portraits with a "photographic quality" from between 1450 and 1565 and found that the pictures all had a magnification of ~90%, and the depicted heads and shoulders all stayed within a circumference of 30 to 50 cm, which corresponded with the sizes of sufficiently clear images projected with the mirror lens.
Secret Knowledge
In his book Secret Knowledge (2001), Hockney argues that early Renaissance artists such as Jan van Eyck and Lorenzo Lotto used concave mirrors; as evidence, he points to the chandelier in Van Eyck's Arnolfini Portrait, the ear in Van Eyck's portrait of Cardinal Albergati, and the carpet in Lotto's Husband and Wife. Hockney suggests that later artists, beginning with Caravaggio, used convex mirrors as well, to achieve a large field of view.
Secret Knowledge recounts Hockney's search for evidence of optical aids in the work of earlier artists, including the assembly of a "Great Wall" of the history of Western art. The 15th century work of Jan van Eyck seems to be the turning point, he argues, after which elements of realism became increasingly prominent. He correlates shifts toward increased realism with advances in optical technologies.
The optical look Many details that are very difficult to depict by eyeballing them, seem remarkably naturalistically painted after the 15th century turning point. Hockney noticed for instance how patterns on clothes perfectly follow complex folds, while clothing previously was painted in a simple graphic manner. Foreshortened curved objects like lutes and pages of a book started to look very accurate in renaissance paintings. While such subjects would be extremely difficult to paint even with technical aids like the frame and chord method known from a 1525 woodcut by Dürer, it is much easier with optical projections (Hockney 2001 p. 36–57).
Hockney tested a technique with a small concave mirror projecting the view from a small open window onto a surface in a darkened room. He associated several of the limitations of the technique and the characteristics of the projected images with the look of many naturalistic paintings: strong lights and shadows, dark backgrounds, limited depth, and a head-on perspective. The use of strong light is also indicated by the small pupils in Van Eyck's portrait of cardinal Albergati, and Hockney suggested that the shelf and ledges at the bottom of many portraits and still lifes, as well as similarities in composition and lighting could be related to this "hole-in-the-wall" technique. According to Hockney, even the establishment of still life as a genre in the 15th and 16th centuries might be connected to the ease of using inanimate objects for the projected imagery. He stressed that not all the artists used the mirror-lens; many could have imitated the look from the works of those who did (p. 74–81, 104–112).
When lenses became large and good enough for wider projections with camera obscuras, artists would have recognised the advantage and Hockney believes this explains the very influential style of Caravaggio's paintings (p. 112).
Distortions Hockney argued that the accurate anamorphic skull in Holbein's The Ambassadors (1533) could have been made with the help of a projection on a tilted surface (p. 57). He recognised less obvious distortions that could similarly (but incidentally) have been caused by a slight tilt of the canvas in the apparently "squeezed up" skull in Francisco de Zurbarán's St. Franciscus at Prayer (circa 1638–39), and in the figure of Jan van Bylert's Man in Armour Holding a Pike (circa 1630) (p. 179).
Montage technique
Hockney suggested that master painters who used projections would often piece together their compositions from different elements. Most elements would be drawn or painted from a straight on viewpoint, although this doesn't always match their place in the linear perspective of the overall composition. The consecutive projections of the different parts sometimes seem to have caused distorted proportions that are not immediately obvious, but would not as soon occur if the master would have sketched out the composition by eye (pp. 112,172–177)
Further publications by Hockney and Falco After their initial papers and Hockney's book, Hockney and Falco continued publishing about their theory.
At a scientific conference in February 2007, Falco argued that the Arabic physicist Ibn al-Haytham's (965–1040) work on optics, in his Book of Optics, may have influenced the use of optical aids by Renaissance artists. Falco said that his and Hockney's examples of Renaissance art "demonstrate a continuum in the use of optics by artists from c. 1430, arguably initiated as a result of Ibn al-Haytham's influence, until today."
Reception