The painting above is called Portrait of Cecelia Gallerani. I am not sure if I have ever heard of it. Most people just know it as The Lady with the Ermine. Yet there really is something perfect about it. Perhaps the most astonishing aspect of the painting is the mustelid itself:
The hand shows an understanding of anatomical structure and a power of particularization none of Leonardo’s pupils possessed. But most convincing of all is the beast. The modelling of its head is a miracle; we can feel the structure of the skull, the quality of the skin, the lie of the fur. None but Leonardo could have conveyed its stoatish character, sleek, predatory, alert, yet with a kind of heraldic dignity.
After countless imitations and parodies, the Mona Lisa still transfixes us. Better yet to see it outside of its bulletproof glass and artificial lights of its sunken well in the museum, moved to the pure sunlight:
How exquisitely lovely the Mona Lisa must have been when Vasari saw her; for of course his description of her fresh rosy colouring must be perfectly accurate. She is beautiful enough even now, heaven knows, if we could see her properly. Anyone who has had the privilege of seeing the Mona Lisa taken down, out of the deep well in which she hangs, and carried to the light will remember the wonderful transformation that takes place. The presence that rises before one, so much larger and more majestic than one had imagined, is no longer a diver in deep seas. In the sunshine something of the warm life which Vasari admired comes back to her, and tinges her cheeks and lips, and we Lucy reading Leonardo can understand how he saw her as being primarily a masterpiece of naturalism.
Both quotes from Kenneth Clark, Leonardo de Vinci (1939), probably the best Da Vinci book of the past century.