1. Introduction

The Hockney-Falco Thesis: Our thesis is that certain elements in certain paintings made as early as c1430 were produced as a result of the artist using either concave mirrors or refractive lenses to project the images of objects illuminated by sunlight onto his board/canvas. The artist then traced some portions of the projected images, made sufficient marks to capture only the optical perspective of other portions, and altered or completely ignored yet other portions where the projections did not suit his artistic vision. As a result, these paintings are composites containing elements that are “eyeballed” along with ones that are “optics-based.” Further, starting at the same time, the unique look of the projected image began to exert a strong influence on the appearance of other works even where optical projections had not been directly used as an aid.

This site contains the historical, artistic and scientific information needed to evaluate and understand this thesis in detail. Thanks to an ‘Education and Outreach’ grant from the Society of Photo-optical Instrumentation Engineers (SPIE), it contains the necessary content for college and pre-college art and science instructors to teach a variety of important concepts in art and optics, with the images and text throughout the site suitable for all ages and cultural backgrounds.

Numerous paintings containing optics-based elements are identified in David Hockney’s Secret Knowledge (Thames & Hudson; Viking Studio, 2001; Expanded Edition 2006) and in our scientific papers published starting in 2000. As we developed new computerized image analysis techniques we reanalyzed some of these same optics-based elements, as well as identified additional ones. In all cases these more recent results not only confirmed our original findings, they revealed additional information about the images, all of which has been in complete agreement with our thesis.

BBC Omnibus, The Charlie Rose Show, Hockney at the Tate, and CBS 60 Minutes

CBS 60 Minutes, introduction to a lecture I gave in 1999 at the National Institute of Standards and Technology, BBC Omnibus, and Discovery Canada.

CBS 60 Minutes ©2002

“Here’s what’s so revolutionary about what you’re saying. You’re saying the history of art, the history of the Renaissance, is the history of optics.”

In January 2002 art historian Laurie Fendrich wrote that our thesis “…shakes the foundations of much of art history, as well as realist painting as an art form.” She continued that “To understand fully the revolutionary nature” of our thesis “it helps to know that not one of the major art-history textbooks commonly used in American art-history survey courses…contains the word ‘lens’ in the index.”

(on the fact that concave mirrors can be used to project images)

©2001 The Charlie Rose Show

Given the huge shift in understanding necessitated by accepting that artists as important as van Eyck used optics, it is not surprising that Fendrich observed that “many [art historians]… weren’t buying it at all.” However, as historian of science Thomas Kuhn wrote in The Structure of Scientific Revolutions, a paradigm shift never happens suddenly, but only as the end result of a long and difficult process. The references at the bottom of Section 9 show that the slow process toward understanding and acceptance of our thesis has made significant progress in the years since Fendrich observed that art historians “weren’t buying it.” Other recent examples are that at the 2008 annual meeting of the National Art Education Association I presented ‘The Ziegfeld Lecture’, awarded for my role in developing the Hockney-Falco thesis, and for its significance for art education, presented a public lecture at the Metropolitan Museum of Art on ‘The Science of Optics; The History of Art’ (in five segments on YouTube 1 2 3 4 5) as part of their contribution to the World Science Festival (May 28–June 1, 2008), and along with David Hockney was “Guest of Honor” at a conference of art historians in Italy exploring Caravaggio’s possible use of optics (September 7–9, 2008). Also in 2008 the SPIE (the international optical engineering society) awarded me an SPIE ‘Education and Outreach Grant’ to develop materials based on our discoveries in order to interest students in the science of optics using content of the type described in this FAQ, and elected me Fellow for “achievements in x-ray optics, optics and art history.”

Although a few of the art and science historians who initially were skeptical also have come to at least partially accept it, art historian Martin Kemp wrote in 2007 that overall “The scholarly response has been … often in the most blinkered manner. This has occurred even where, as in the case of Vermeer, the evidence about the use of optical devices is as about secure as it could be.” However, secure as the evidence is, wide acceptance of our “revolutionary” thesis after only a few years would be too much to hope for, especially in light of physicist Max Planck’s observation that “a new scientific truth does not triumph by convincing its opponents…, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.”

Within the first five months after publication of David Hockney’s Secret Knowledge (Thames & Hudson; Viking Studio, 2001; Expanded Edition 2006) over 100 newspaper and magazine articles already had appeared that discussed the discoveries in that book, and millions more saw television programs including a BBC special and CBS’s 60 Minutes. As a result of me being mentioned as Hockney’s scientific collaborator, I was overwhelmed with emails and letters on the subject. Unfortunately, there were far too many letters for me to to reply to each one individually. However, many of the same questions were asked by more than one person, either in writing or at the more than 150 seminars and public lectures on this topic I have given thus far since 2000, resulting in me compiling the information on this web site. However, without sacrificing accuracy for brevity, I have created this web site primarily for non-specialists, so you will not find the detailed footnotes, extensive descriptions, qualifying remarks, or lengthy explanations that would be present if it were a manuscript written for a scholarly publication to be read by academic experts. If you have a question that is not answered on this site, please send it to me and I will address it here if it is of general enough interest.

After having made the visual and scientific case for the direct use of optical projections, David Hockney became increasingly interested in the indirect use of optics by artists. That is, he felt that having seen 3-dimensional scenes projected onto 2-dimensional surfaces would have strongly influenced artists even when they did not directly use projections for a particular painting (e.g. John Keane chose to render the background of a recent portrait out of focus, similar to the look of a photograph). More recently, Hockney returned to landscapes, recently finishing his largest painting ever ‘Bigger Trees near Warter’ (40×15 ft., 2007). The subtitle he gave this work, ‘Peinture en Plein Air pour l’age Post-Photographique’, shows that what he learned from the optics of the Old Masters has informed this new “post-photographic” direction he is now exploring with his own art (in 2008 he donated this painting to the Tate Britain). As he observed, “Photographs see surfaces, not space,” and he is interested in creating visual spaces with paintings that he believes are beyond what can be done with photographs.

By 2003 David Hockney and I had assembled a wide range of scientific evidence that demonstrated optical projections had been used by a number of artists. As a central part of our investigations we had experimentally verified every aspect of our calculations (e.g. we made our own metal concave mirrors using the same process as detailed in a pre-1372 manuscript, used these hand-made mirrors to project life-size images that quantitatively reproduced all of the complex features of Lotto’s carpet, of van Eyck’s drawing and painting of Cardinal Albergati, etc.), so by 2003 my own visual interests also started evolving in a new direction. Other than our initial paper in 2000, all of our subsequent scientific publications on this topic have been solicited by academic editors and conference program committees to go with invited talks. My research program in optical physics (i.e. Brillouin light scattering, x-ray optics, etc.) has continued throughout, but I also began to apply the visual insights that came from working with Hockney to develop a new approach to computerized image analysis. A talk on The Tyranny of the Lens that I gave in 2009 at the Minneapolis Institute of Arts is related to this. This ongoing research program has combined for the first time the visual insights from an artist as skilled as David Hockney, with the mathematical and scientific background of a scientist.

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