Have you ever wondered why some modern art sells for record-breaking millions? What, for example, makes Andy Warhol’s “Colored Mona Lisa,” – Da Vinci’s portrait that the Pop artist silkscreened 24 times in different colors -- worth the $56.2 million that it sold for at Christie’s last year? Reportedly, Warhol created the work (if you call re-coloring an Old Master his creation) to profit from the Louvre’s historic loan of the Renaissance masterpiece to the Met in 1963.

Reasons why a painting sells for astronomical amounts can be surprisingly simple, such as bartering for what the market will bear. (Of course, you might say that Warhol gave the market a nudge by capitalizing on a big event).

Change of heart

But cynicism doesn’t always rule sales. Consider last week’s auction of “Two Nudes in the Forest,” a painting by Frida Kahlo for $8.2 million. OK it doesn’t come close to the zenith that Warhol reached, but it exceeded Kahlo’s auction history of $5.6. And one look at the work suggests why the bidding went so high that even Madonna, who sought the purchase, was outbid.

What you see are two figures, Kahlo and her longtime friend Mexican actress Dolores Del Rio at rest, serene in a lush landscape. What makes this serene painting special is what makes so many of Kahlo’s other paintings of herself un-serene. There’s no sign of her numerous spinal surgeries from an accident she suffered in her youth that she so routinely pictured, as in “The Broken Column,” which describes her enfettered in a heavy brace. “Two Nudes in the Forest” speaks of love, not illness.

In sickness and in health

Not only is Kahlo’s painting unusual for he, but it’s also out of the ordinary in modern #Art. Ask yourself, when did you last see an image of love in art? Try 1913! Oskar Kokoschka’s “The Bride of the Wind,” which shows him with Alma Mahler (Gustave Mahler’s wife) in a stormy whirl of bed sheets. And before that, when? How about 1665? Rembrandt’s “The Jewish Bride,” a portrait of a couple looking away from the viewer, touching each other, clearly fixed on their own moment.

Seeing Kahlo’s picture of contentment is so unexpected, it’s like looking at, say, a painting by Edvard Munch, famed for “The Scream,” or any of his numerous visions of sickness and death in a loving embrace with someone, anyone.

So in between 1665 and 1939, the year that Kahlo painted a picture of friendship, some 174 years later, there’s not much in the way of art making that portrays happy relationships.

Another way to appreciate how unusual “Two Nudes in the Forest” is would be to recall the portrait that Kahlo painted for Clare Booth Luce to memorialize Luce’s friend Dorothy Hale who died by her own hand. What Lucy got was a “gruesome” picture of her friend’s corpse.

Novelty can drive the price of art. How else to explain Damien Hirst’s dead tiger shark preserved in formaldehyde auctioned in 2004 for $12 million? #Buzz