Possibly the most famous work of Leonardo da Vinci was his Mona Lisa. It is, in fact, so famous that even as I type this, MS Word knows not to try and correct either Mona or Lisa (despite drawing red lines under the artist’s name). Coincidence though that may be, every one of us knows what it looks like, having seen it on television, film, advertisements and postcards. Pretty though it may seem to us, we know little of what the sixteenth century Florentines thought of it. Sadly, now, the original in the Louvre is kept behind a sheet of bullet-proof glass and an impenetrable layer of tourists many of whose sole intent is to be able to tick a box on their sightseeing sheet. If you tried to take a picture of the painting, all that would come out would be the reflection of a thousand faces (mostly, though I hate to stereotype, Japanese). The painting’s popularity has grown out of proportion, and most of the people who want to see it do not necessarily wish (or know how) to appreciate the artistic genius involved in its creation: somehow, the woman in the picture seems to be smiling pleasantly, sometimes sadly. She looks a little different every time we see her. She looks alive.

This effect is more deliberate and calculated than anyone who knew nothing about the painting’s creation could imagine. Leonardo studied the form of the human face (as he did with almost everything else). He knew more about the way we use our eyes than anyone who had gone before him. In his painting, he combined the correct depiction of a form with ‘harmonious composition’, in other words, making it lifelike. Many Italian masters had been able to do stunningly accurate drawings of animals and plants, but in doing so, all impression of movement or life is removed. Leonardo, with his insatiable curiosity and intelligence to back it up, realised that the more consciously we try to make something accurate, the less real it seems. This can be seen to be the case in the works of Mantegna, who was an expert in correct drawing and perspective but whose people looked more like statues than anything else.

Leonardo’s solution was his famous invention, sfumato – the technique of using blurred and mellow colours to merge one shape into another, always leaving something to our imagination. He found that the places most indicative of mood and expression were the corners of the mouth and eyes. If you look at the painting, you will see that these are the places that Leonardo has left indistinct, by letting them merge into a soft shadow. However, that is not da Vinci’s only secret weapon – you will see if you look at the picture that the horizon on the left seems to be lower than on the right. This gives the impression that, when you focus on the left, she is somehow taller than when you focus on the right. However, all this amounts to nothing other than a series of mathematical tricks if you cannot give the person in the chair the right form and shape, and Leonardo does this with great skill – he ‘fleshes out’ her form and paints her sleeve with its tiny creases and folds with such skill and expertise that it is hard for us to think that he could have been anything other than a genius.