“Why does sexual obsession so suit the medium of painting? Why does paint make lust eloquent?”

This tricky question was posed by John Berger, art critic and host of the superb BBC series Ways of Seeing. On the television show, Berger singled out Titian as someone who intuitively understood that when a paint hue is based on the natural pigmentation of human beings, it triggers our biological reflexes and our sexual imagination.

The woman in Titian’s Venus with a Mirror oozes with desirability. It’s not the nudity, it’s the paint. Color can be very sensual.

She is looking over her shoulder and acknowledging her reflection in the mirror by placing her left hand on the center of her chest. Does she feel attractive? How important is feeling attractive to female sexual desire?

Two cupids attend to her because she is Venus, the mythological goddess of love and beauty. One cupid holds a mirror, while the other reaches to crown her with a garland of myrtle. To create the woman’s pose, Titian added the impression of movement to an ancient statue he admired. But his Venus isn’t cold as stone. He put so much red pigment in her flesh tones, we sense the blood flowing through her veins.

Titian liked to say a good artist needs only three paint colors: black, white, and red. He was exaggerating, but not by much. His triple portrait of Pope Paul III and his two succession-obsessed grandsons proves his point.

Titian painted more than twenty portraits of Venus, but only one — the canvas hanging in the National Gallery of Art in Washington D.C. — was completed entirely by his own hand, without the aid of studio assistants.

A tour de force of brushwork hiding in plain sight

X-radiographs reveal he painted the Washington picture directly over an older picture: a portrait of a man and woman standing side by side. The artist rotated the canvas 90 degrees and left the fur coat of the male figure exposed, reconfiguring the garment into the luxurious robe that now hugs Venus’s hips.

This painting was one of a marching band of portraits lined up in Titian’s orderly workshop. Each canvas advertised a popular theme like The Penitent Magdalene — the figure of a young woman fasting in the desert wearing nothing but her long, voluptuously disheveled hair. When asked how a starving woman could be in such robust health, Titian replied with a twinkle that perhaps this was the first day of her fast.

The importance of a good mentor

Tiziano Vecellio (Titian) was born in a small mountain town in the Italian Dolomites. As a boy, it’s said he made colors from berry juice and flowers, then painted a portrait on the side of a house. No word on how his parents reacted to this escapade, but when Titian was ten years old he was sent to live with his aunt and uncle in Venice.

The kid must have had talent because just a few years later he entered the workshop of Giovanni Bellini, the most prominent painter in Venice. Bellini’s network included Giorgio Barbarelli da Castelfranco (Giorgione), a former student ten years older than Titian. Giorgione encouraged the lad’s predilection for sensuous pigments and the illusion of movement.

Giorgione was a cult figure among the young noblemen who thought of themselves as the intellectual vanguard of Venice. He was the first local painter to be admired because his paintings looked unlike the work of other artists.

A fundamental painting in his catalogue is The Old Woman, a portrait that is one of the most startling and engaging images of the Italian Renaissance.

The woman — who may or may not be Giorgione’s mother — has thinning gray hair and weathered skin. She wears a pretty shawl that covers part of her blouse. Age makes her gentle expression hard to read. Is she tired? Sad? Trying to smile?

Like Venus, she places her hand on the center of her chest, although now the gesture registers differently. Giorgione tucked a note in her sleeve, to send us a gentle reminder about aging: Col Tempo (With Time). Tell me about it.