London, Mar 30 (ANI): Analysing a 16th-century artwork dubbed a "Rosetta stone" for optical techniques, art experts have said that some Renaissance artists used lenses or mirrors to help them paint more accurately.
In 2000, artist David Hockney and optical scientist Charles Falco of the University of Arizona in Tucson, proposed the theory that Renaissance artists used optical projection.
But, their theory has failed to convince art historians to date.
Falco and Hockney claim to have spotted the signature of optical projection, perhaps using a concave mirror, in a painting created more than a century earlier.
Falco presented detailed analysis of 'Husband and Wife', a 1525 work by Lorenzo Lotto, at the American Physical Society (APS) meeting in Portland, Oregon, last week.
"We call it the Rosetta stone because we got so much information from it," New Scientist quoted Falco as saying.
The pair has argued that distortions in the oriental carpet match what would be expected if Lotto had projected the image, traced out part of it, then moved his mirror twice to bring two other portions of the carpet into focus.
For example, there are multiple vanishing points, suggesting it was painted from different perspectives.
They also pointed out that the back of the octagonal pattern is blurred, as if traced out of focus.
Falco also presented images of the painting taken using an infrared camera.
Beneath the red paint of the carpet, he found a region of neat sketch lines, a region of hazy lines, and a region of no lines-all these correspond to the three regions he and Hockney think have been painted with different focuses.
Falco believes the decline in the quality of the sketch lines reflects Lotto's struggle to keep the pattern on the carpet coherent after changes in focus, which would also have slightly altered the magnification of the image.
However, optical scientist David Stork of Ricoh Innovations in Menlo Park, California, still remains sceptical.
Stork said that as the red paint covers the sketch lines, they could not have been seen when Lotto was painting the geometrical pattern on top, making them irrelevant.
"This evidence is consistent with traditional, non-optical explanations," he said. (ANI)