"(Artist) David Hockney, and a physicist, Charles Falco, first put forward the idea that the Old Masters may have used optics to help with realism and accuracy in the year 2000," said Francis O'Neill, an independent researcher based in UK.
"However, this was met with some scepticism, with the realism shown in some self-portraits used as an argument that these artists would not need optics for other works," said O'Neill, one of the authors of the study published in the Journal of Optics.
Five setups are proposed by the authors - one using solely a concave mirror, and three using a combination of a flat and a concave mirror, and one using two flat mirrors and a lens.
The researchers also analysed the works of Rembrandt, an artist well-known for his highly-detailed self-portraits.
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"He made etchings and even a couple of painted self-portraits on copper, a surface upon which projections can be seen very clearly," said O'Neill.
"Furthermore, his self-portraits laughing and with wide-open eyes would require incredible physical discipline to alternate between looking at himself in the mirror and then creating the image - but he wouldn't have had to move his eyes from the drawing surface if he traced a projection," he added.
"On a separate point, both Rembrandt and other Old Masters made paintings in which their eyes look laterally out of the image. It would have been very difficult for them to see and paint themselves this way without the use of projections," said O'Neill.
His etched self-portraits are also generally very small. The researchers found these anomalies to be necessary for the projection process.
"The similarity of his images to projections, in their lighting and soft focus, along with the use of lens technology by his peers and fellow artists, and the contemporary literature on the subject, all support this," said O'Neill.