Leonardo used a pyramid design to place the woman simply and calmly in the space of the painting. Her folded hands form the front corner of the pyramid. Her breast, neck and face glow in the same light that models her hands. The light gives the variety of living surfaces an underlying geometry of spheres and circles. Leonardo referred to a seemingly simple formula for seated female figure: the images of seated Madonna, which were widespread at the time. He effectively modified this formula in order to create the visual impression of distance between the sitter and the observer. The armrest of the chair functions as a dividing element between Mona Lisa and the viewer.
The woman sits markedly upright with her arms folded, which is also a sign of her reserved posture. Only her gaze is fixed on the observer and seems to welcome him to this silent communication. Since the brightly lit face is practically framed with various much darker elements (hair, veil, shadows), the observer's attraction to Mona Lisa's face is brought to even greater extent. Thus, the composition of the figure evokes an ambiguous effect: we are attracted to this mysterious woman but have to stay at a distance as if she were a divine creature. There is no indication of an intimate dialogue between the woman and the observer as is the case in the Portrait of Baldassare Castiglione (Louvre) painted by Raphael about ten years after Mona Lisa, and undoubtedly influenced by Leonardo's portrait.
The painting was among the first portraits to depict the sitter before an imaginary landscape. The enigmatic woman is portrayed seated in what appears to be an open loggia with dark pillar bases on either side. Behind her a vast landscape recedes to icy mountains. Winding paths and a distant bridge give only the slightest indications of human presence. The sensuous curves of the woman's hair and clothing, created through sfumato, are echoed in the undulating imaginary valleys and rivers behind her. The blurred outlines, graceful figure, dramatic contrasts of light and dark, and overall feeling of calm are characteristic of Leonardo's style. Due to the expressive synthesis that Leonardo achieved between sitter and landscape it is arguable whether Mona Lisa should be considered as a traditional portrait, for it represents an ideal rather than a real woman. The sense of overall harmony achieved in the painting - especially apparent in the sitter's faint smile - reflects Leonardo's idea of a link connecting humanity and nature.
Mona Lisa has no visible facial hair - including eyebrows and eyelashes. Some researchers claim that it was common at this time for genteel women to pluck them out, since they were considered to be unsightly. For modern viewers the missing eyebrows add to the slightly semi-abstract quality of the face.
(From Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Mona_Lisa)