Technical Specifications
77 × 53 cm · Oil on white poplar (Populus alba). Leonardo built up incredibly thin translucent glazes — reportedly up to 30 layers, each as thin as 1–2 micrometers (increasing to 30–40 μm in shadows). Total combined layers are less than 40 micrometers — about half the thickness of a human hair.
Currently behind multi-layered, laminated, anti-reflective bulletproof glass maintaining 50% ±10% humidity and 18–21°C. A crack extends from near the top down to the hairline. Multiple layers of yellowed varnish have darkened the painting substantially — the Louvre has never attempted a major cleaning.
The 1911 Theft
Vincenzo Peruggia, an Italian handyman who had helped construct the painting's protective glass case, hid overnight on August 21, 1911. He emerged at 7:15 AM, lifted the painting off the wall, removed the glass in a stairwell, and walked out with it under his smock. A plumber unlocked a stuck service door for him.
The theft wasn't discovered for 28 hours. Guillaume Apollinaire was arrested and implicated Pablo Picasso — both were released. Peruggia's thumbprint was on the glass and in police files, but investigators never cross-referenced. After two years hiding the painting in his apartment, he was arrested in Florence and served only seven months.
Pascal Cotte's Multispectral Revelations
French engineer Pascal Cotte spent 15+ years analyzing 1,650+ images captured with an ultra-high-resolution multispectral camera. His Layer Amplification Method processes up to 3.2 billion data points. Key discoveries:
- Spolvero underdrawing — charcoal pouncing proves a preparatory cartoon was used, meaning a Leonardo drawing of the Mona Lisa may still exist
- Evidence of up to four superimposed portraits — an entirely different woman beneath the current surface
- A hidden pearl headdress in the underdrawing, later removed
- The original Mona Lisa apparently didn't smile
- Eyebrows and eyelashes were originally painted (consistent with Vasari), gradually lost to overcleaning
The Smile as Optical Illusion
Harvard neuroscientist Margaret Livingstone (2003) demonstrated the smile's enigmatic quality exploits the difference between foveal and peripheral vision. Look directly at the mouth: the smile fades. Look at the eyes: it returns. Peripheral vision detects shadows around the cheeks that expand the smile when perceived indirectly. Leonardo's sfumato exploits this neurological reality — centuries before the science was understood.
The Sfumato Mystery Decoded
C2RMF scientists mapped the paint structure: priming layer of lead white → flesh-tone paint → sfumato shadowing glaze → varnish. In darker areas, manganese-containing glaze is applied more thickly. Scientists describe an "airbrush-like" effect achieved centuries before airbrushes existed. Each glaze layer required weeks to months of drying time, explaining why Leonardo worked on it for 4–16 years.
The complete absence of visible brushwork confirms Leonardo used his fingertips, soft cloths, and possibly feathers rather than brushes for final blending.
Identity & Provenance
The 2005 discovery of a marginal note by Agostino Vespucci confirmed Leonardo was painting Lisa Gherardini, wife of Francesco del Giocondo, in October 1503.