Isleworth Mona Lisa
According to Leonardo's early biographer Giorgio Vasari, Leonardo had started to paint "Mona Lisa" in 1503, but "left it unfinished". However, a fully finished painting of a "certain Florentine lady" surfaced again in 1517, shortly before Leonardo's death and in his private possession. The latter painting almost certainly is the one that now hangs in the Louvre. Based on this contradiction, supporters of the authenticity of the "Isleworth Mona Lisa" claim it is the unfinished "Mona Lisa", made at least partially by Leonardo, and the Louvre "Mona Lisa" a later version of it, made by Leonardo for his own use.
Mona Lisa
"Mona Lisa" has no clearly visible eyebrows or eyelashes. Some researchers claim that it was common at this time for genteel women to pluck these hairs, as they were considered unsightly. In 2007, French engineer Pascal Cotte announced that his ultra-high resolution scans of the painting provide evidence that "Mona Lisa" was originally painted with eyelashes and with visible eyebrows, but that these had gradually disappeared over time, perhaps as a result of overcleaning. Cotte discovered the painting had been reworked several times, with changes made to the size of the Mona Lisa's face and the direction of her gaze. He also found that in one layer the subject was depicted wearing numerous hairpins and a headdress adorned with pearls which was later scrubbed out and overpainted.