July 2 (Bloomberg) -- Ira Spanierman has done what most art dealers only dream about.

Poking around a Sotheby Parke Bernet (now Sotheby's) auction preview in 1968, Spanierman spied a painting of a bearded man in an ornate gold-and-raspberry vestment that was ascribed to an unknown artist of the Italian school. The young dealer, who had founded Spanierman Gallery just a short time before, bid $325 for the canvas -- and won it.

Three years later, leading Renaissance scholars identified the work as a lost 1518 portrait of Lorenzo de' Medici by Raphael. Spanierman was thrilled.

Almost four decades after his purchase and discovery, Spanierman has placed the Raphael with Christie's International to be auctioned on July 5 -- during London's old master sales at Christie's and Sotheby's tomorrow through July 6. The work has a top estimate of 15 million pounds ($30 million).

The offering is unusual: Most Raphaels hang in major museums and rarely come to auction.

Christie's has guaranteed the painting and will pay Spanierman an undisclosed agreed-upon amount regardless of the sale's outcome. (The guarantee is often close to the low estimate, which in this case is 10 million pounds.)

Spanierman, 78, with sleek white hair, a violet shirt and an East Hampton tan, sat down to chat about the auction. We met at his 58th Street gallery, surrounded by stacks of art books, family photos and mementos from a lifetime in the business of art. He has concentrated on 19th- and 20th-century U.S. painting, selling artists such as Winslow Homer and William Merritt Chase.

Ladder Viewing

Pollock: Tell me about discovering this painting.

Spanierman: There was an auction preview and it wasn't considered a good sale. They hung it salon style, so things were really very high and you couldn't see them. In those days I was clambering up ladders like a monkey with my magnifying glass. I looked at everything.

Pollock: What appealed to you about the portrait?

Spanierman: I could see the quality of the hand and the fur collar, the lighter parts of the painting. Otherwise it was filthy dirty and impossible to see and in a terrible 19th- century plaster frame.

Pollock: So what did you think?

Spanierman: I didn't know what it was, but I felt good about the painting so I bought it. I had a fellow working for me who was a restorer and once I got it there we saw a label on the back that said it had been exhibited as a Raphael.

Uncovering Colors

Pollock: How did it change once you cleaned it?

Spanierman: These beautiful colors came up. You couldn't see it before. Then I did research and got in touch with some scholars.

Pollock: Is this your greatest find?

Spanierman: I've made other discoveries, but nothing like this. This is a miracle.

Pollock: Could a discovery like this happen today?

Spanierman: Most of the things that come to auction, they clean them if they think they are worth something. Years ago people used to find things all the time. It became less and less possible.

Pollock: Why are you selling now?

Spanierman: Because it came to a moment that if I want to enjoy the fruits and economic value of it, I would have to sell now, because I'll be dead later on.

Pollock: Why sell at auction?

Spanierman: Dealers used to run the art business, and now I have to say, with a few exceptions, the auction houses run the business. They have the widest audience.

Pollock: After looking at the painting for years, what did you learn about Lorenzo de' Medici?

No Pushover

Spanierman: He's dressed in fancy French clothes because his uncle, Pope Leo X, arranged his marriage to make an alliance with the French and dressed him up like this. But he's not happy being dressed up. I think he's saying ``I may be dressed up, but don't think I'm a pushover.'' You can see the pommel of his dagger sticking out under the wraps of his clothes.

Pollock: Are you going to attend the sale in London?

Spanierman: No!

Pollock: How come you don't want to watch? David Rockefeller saw his Rothko sell at Sotheby's.

Spanierman: The sale of that Rothko wasn't as important to David Rockefeller as this is for me. I hear he had some money already.

Christie's values its old master sales this week at as much as 52 million pounds before commissions, including the Raphael and pictures from the Jacques Goudstikker collection that have a 5 million pound top estimate. Last year's total was 32.1 million pounds with commissions.

Sotheby's old master sales, including Turner watercolors from the Belgian collector Guy Ullens on July 4, have a high valuation of 49.3 million pounds pre-commission. Last year's sales totaled 30.7 million pounds including commission. London dealers are selling old master drawings through July 6.

Sotheby's holds the old master painting record, for a Rubens that fetched 49.5 million pounds including commission in 2002.

(Lindsay Pollock writes on the art market for Bloomberg News. The opinions expressed are her own.)

To contact the reporter of this story: Lindsay Pollock in New York at lindsaypollock@yahoo.com.

Last Updated: July 2, 2007 00:18 EDT