NEW YORK, Dec. 13 (UPI) -- Have artists since the 15th century been using optics in the form of camera-like devices to create more perfect paintings without letting the public in on their secret?
In other words, have they been cheating?
That is the question raised by David Hockney, the British artist who calls California home, in a recent book and at a symposium arranged by the New York University's Institute for the Humanities. There are convincing arguments -- pro and con -- and the subject probably will come under scrutiny for years to come.
It all started when Philip Steadman's book, "Vermeer's Camera," was published earlier this year about 17th century optical instruments, chiefly the camera obscura, used by Jan Vermeer and possibly other Dutch artists to obtain perfect perspective in their work. An exhibition at New York's Metropolitan Museum of Delft art in the time of Vermeer even displayed a camera obscura, a lens that projects an upside-down image in a dark room.
The point being made was that Vermeer traced the image to obtain greater accuracy in his paintings of interior scenes with one or more people in them.
Then along comes Hockney with his recently published book titled "Secret Knowledge: Rediscovering the Lost Techniques of the Old Masters," in which he claims artists as early as the 1420s, particularly Flemish master Jan van Eyck, used optical devices to help them produce more realistic images. From that century on, Western art was decidedly more naturalistic.
"From the 15th century many Western artists used optics -- by which I mean mirrors and lenses (or a combination of the two) -- to create living projections," Hockney wrote.
"Some artists used these projected images directly to produce drawings and paintings, and before long this new way of depicting the world -- this new way of seeing -- had become widespread. It is inconceivable that artists wouldn't have used such devices."
Hockney's list of suspects includes Lorenzo Lotto, Caravaggio, Titian, Raphael, Rubens, Velazquez and Ingres, although there are no eyewitness accounts or other documentation, not even a line in a letter or a diary, to prove the use of optical aids. After the advent of photography, artists worked directly from photo images, secretly in the case of Thomas Eakins, the great American painter of the late 19th century, and openly in the case of Andy Warhol in the late 20th century.
It was an exhibit of paintings and drawings by J.A.D. Ingres in London in 1999 that piqued Hockney's interest because the lines in the drawings were so clean, fast and completely assured, reminding him of the photo-traced drawings of Warhol. Ingres, Hockney believes, used some sort of refracting instrument such as the camera lucida, a prism at the end of a rod that allows an artist to see the face of a subject in the prism so it can be accurately sketched.
These assertions have raised the hackles of many art historians and critics, who believe the human eye is as good an instrument at any at catching accurate images, and led to the symposium early this month at New York University. Hockney and his scientific mentor, Charles Falco, a professor of optical sciences at the University of Arizona, presented a 75-minute BBC film outlining their theory to an overflow audience.
The documentary, including many paintings, tried to show that they were too lifelike to have been "eyeballed" and drawn freehand, but at the same time were in part out of focus like photographs. Some paintings have multiple vanishing points as though the artist had focused and refocused a lens to paint different parts of a picture.
"I am not saying that these people traced the images," Hockney said, taking a step back from assertions made in his book. "Optics don't make art. But to see them is to use them."
This did not mollify his critics. Keith Christiansen, a curator at the Metropolitan Museum, said artists like Caravaggio and Raphael had no need for fuzzy optic images because they made freehand preparatory sketches for their paintings. Cultural critic Susan Sontag argued that to say there were no great painters before optics was like saying there were no great lovers before Viagra.
Others claimed to have experimented with various optical devices and found them ineffective in projecting clear images. Steadman, author of the book about Vermeer and the camera obscura, claimed just the opposite and pointed out that six of Vermeer's paintings actually are different viewpoints of the same room all done on the same size canvas.
"Why is this?" he asked. "Because he traced them using images created in a camera obscura."
This didn't convince Walter Liedtke, another Metropolitan Museum curator who organized the Delft artists show. He said it was possible that Vermeer was interested in the camera obscura but that he had evidence that the artist's rooms were "pure invention." Steadman replied that Liedtke was suffering from "mimesophobia," the morbid fear of slavish imitation.
The matter of Eakins came into the discussion because his practice of painting from magic lantern projections of photographs was revealed at the current retrospective of his art at the Philadelphia Museum of Art, where his 1881 "Shad Fishing at Gloucester on the Delaware River" was displayed next to glass plates of a photo he had taken of the identical scene a few months before. In 1882, a critic hailed him as "the greatest draftsman in American art."
Eakins never admitted his debt to photography, which would have caused a scandal at the time. But using photographs to produce art, as practiced by Warhol and pop portraitist Chuck Close, is no longer something to be ashamed of and is openly acknowledged. That is as it should be.
Machine-made art is ubiquitous today. A current exhibit at the Whitney Museum, "Into the Light: The Projected Image in American Art, 1964-1977" displays the work of 19 artists including Warhol, Bruce Nauman, Robert Morris, Vitol Acconci, and Yoko Ono who use film, video, and slides to produce projection art that curator Chrissie Iles calls "the new language of artmaking."