NEW YORK » Here’s looking at you, piano.

No one would mistake you for Ingrid Bergman, although you and she shared a moment. And what a moment it was. It made you one of the most famous pianos in movie history. You must remember that: The flashback scene in Paris, the one that turned "Casablanca" from simply a war story into one of the most enduring cinematic love stories ever told.

Now you are to be auctioned off at Sotheby’s by an auctioneer who has sold other famous movie props — the "Rosebud" sled from "Citizen Kane," for example. Sotheby’s expects you to sell from $800,000 to $1.2 million in the auction Friday. That is 34 to 48 times what Bergman was paid for sharing top billing with Humphrey Bogart.

And she really had to work. She was in scene after scene. You appeared in only one, in the Parisian cafe known with the words "La Belle Aurore" on the window. Warner Brothers used a different piano in the scenes in Rick’s Cafe Americain. That was the one Bogart slipped those "letters of transit" into, not you.

You were not on camera for long — only about 1 minute 10 seconds. And while you were seen, you were not heard. Dooley Wilson, who played Sam, moved his hands up and down your keyboard as he sang. But he was not actually hitting any notes. Somewhere off camera was a real pianist, performing on another piano.

So moviegoers never really knew what you could do. Seventy years after the movie came out, you had your "Garbo talks" moment — the moment when your voice was finally heard — at Sotheby’s. As your vaguely honky-tonk sound drifted through Sotheby’s exhibition space, a line from a certain song came to mind: The fundamental things apply as time goes by. And time does go by; pianos get old. They can lose the bounce they had when they were young.

You are not really in tune, but not badly out of tune, either, and that is with no help from a piano technician. Sotheby’s said the piano had not been worked on since it was delivered for display several weeks ago.

Considering that "Casablanca" was shot in black and white, a spoiler alert is probably in order here. Readers who want to keep imagining the movie in black and white should skip to the next paragraph. In real life, the piano is green and tan. Sotheby’s said it still had several coats of paint, apparently left over from appearances in other movies, when it was bought by a Los Angeles collector in the 1980s. He scraped off the layers, revealing colors that "Casablanca" audiences could only guess at.

The piano is weathered, and a bit sluggish. It cannot handle the thrill of a trill, as Michael Feinstein — the pianist and singer who, with Ian Jackman, is the author of "The Gershwins and Me: A Personal History in 12 Songs" — found when he tried it at Sotheby’s on Monday.

"It’s not gratifying to play," he said, "but that’s not actually what it’s about."

No. As he said after playing "Someone to Watch Over Me," this piano was a prop. Bogart, who stood 5 feet 9 inches tall, must have liked this piano because it, too, is rather short. He would not have towered over a conventional upright the way he towered this one.

It is also slimmer than most pianos. It has only 58 keys, 30 fewer than a conventional modern instrument.

"It’s a cafe piano," the auctioneer at Sotheby’s, David N. Redden, said. "It was designed to be wheeled from table to table. The pianist would move it to the next table. It’s rather like the violinist coming around to each table."

In "As Time Goes By," Feinstein was well aware of just how limited the keyboard was.

"At a couple of spots," he said, "I was reaching for notes that weren’t there."

He was also aware of its little odor problem, not uncommon among old pianos with dust on the hammers, the strings and the soundboard. Feinstein said he could "actually smell the dust when the keys are depressed."

The piano’s life after "Casablanca" is "a little unclear," Redden said.

"It may have been used in other films," he continued, "although we haven’t identified any."

There is a photograph from a 1943 War Bond drive. It apparently languished in a prop shop for years. (The other piano in "Casablanca," the one from Rick’s Cafe Americain, was sold to the same collector in the 1980s. Sotheby’s says it is now on loan to the Warner Brothers Studio Museum in Burbank, Calif.)

Redden sold the "La Belle Aurore" piano in 1988 for $155,000, at the time the second-highest price for a piece of Hollywood memorabilia. Prices for Hollywood memorabilia have soared since then.

Just as Marilyn Monroe’s dress from "The Seven Year Itch" was not bought to be worn when it went for $4.6 million last year, the "Casablanca" piano will probably not be bought to be played.

"This is memorabilia," Feinstein said. "Nobody’s buying this as a musical instrument. I mean, this is not something Lang Lang would want to have to play. But you can’t put a price on what it is worth to an individual because there’s only one of these.

"I’ve played many pianos through the years that people said George Gershwin played — ‘This belonged to George Gershwin’ — and it’s usually apocryphal. But this is the real thing, and so it’s basically worth whatever someone’s willing to pay for it. And it’s going to be a lot."

© 2012 The New York Times Company