Francis O’Neill, a painter based in England, says Rembrandt’s self-portrait skills were likely aided by the use of science.

Rembrandt not only painted a lot of self-portraits, but he also did so with a level of accuracy and detail that, to this day, astounds many, reports Seeker. 
Francis O’Neill, a painter based in England, says the old master’s skill was likely aided by the use of science, notes the New York Times.
Carefully placed mirrors, both flat and concave, would have created a projected image, albeit upside down, for the 17th century artist to use as a guide.
In arriving at that conclusion, O’Neill and his research partner Sofia Palazzo Corner set up a number of mirror configurations and discovered an arrangement that did the trick. 
The resulting projection also had the wide range of light and darkness characteristic of Rembrandt’s work. 
O’Neill is not the first person to suggest the masters of the day had a little help.
In 2001, David Hockney, in partnership with optical expert Charles Falco, also asserted the artists used lenses and mirrors to create their realistic imagery.