“FINAL PORTRAIT”

****

(R, 1:30)

“Final Portrait” is faithful to its title and a lot more.

Ably written and directed by Stanley Tucci, it examines in detail the drama behind the last painting made by artist Alberto Giacometti, but that is only the start.

Powered by a triumphant performance by Geoffrey Rush as the celebrated painter and sculptor, “Portrait” also serves as an involving examination of the creative process itself, of how difficult it can be to move forward with artistic enterprises no matter how gifted you are or how much regard the world holds you in.

Though usually known as an actor, Tucci has directed several films, and the best of them, like “Joe Gould’s Secret” about the New Yorker writer and “Big Night” about a temperamental chef, are concerned, as this one is, with the nature of the imaginative impulse.

Like them, “Final Portrait” is quietly involving, amusing in a shaggy-dog-story way and impeccably made. Capable costars like Armie Hammer and Tucci’s frequent collaborator Tony Shalhoub are essential, but the center of interest, as Giacometti was in real life, is Rush.

Though Rush’s skills as an actor are well known (he won an Oscar for “Shine” and received three other nominations), his work here is involving in a way that feels completely new and makes a considerable difference.

For the Paris-based, Swiss-born Giacometti, one of the last century’s most renowned artistic figures, is as played by Rush one of those larger-than-life characters, a shambling, grumbling bear riven by almost pathological doubts about the value of his work or even the very possibility of doing work one can be satisfied with.

But while the temptation to chew the scenery with this kind of role must have been considerable, Rush delves so deeply into the performance, his face and the subtle emotions that play over it such a wonder, that you never catch him acting as he creates a character that is never anything but authentic.

Tucci’s film is based on a 1965 memoir called “A Giacometti Portrait” by the late James Lord, a biographer and friend of Giacometti’s who was also an acquaintance of the filmmaker.

Playing Lord as a classic old-school American abroad, given to wearing blue blazers and khaki trousers, is Hammer, who fits easily into a role which has nonsexual echoes of the part he played in “Call Me by Your Name.”

Someone who knew the artist through mutual friends, including Pablo Picasso, Lord was on what he thought was a brief visit to Paris when he was casually asked by Giacometti if he would sit for him.

“It will take two or three hours, an afternoon at most,” Lord was told. “It will be very quick.”

Which is not quite the way it turned out.

Lord got the first hint of this when he turns up at Giacometti’s heroically messy studio and is greeted by the artist’s wife Annette (Sylvie Testud) with a curt “my husband’s next victim.”

As for the brutally realistic Giacometti himself, he takes a close look at Lord and declares “you have the head of a brute, you look like a real thug.”

If Giacometti is tough on everyone around him, he is toughest on himself, and as “Final Portrait” unfolds we experience his despair about his own work, something that plays on screen as blackly comedic, though it is no joke to the people involved.

“It’s hopeless, it’s not worth going on with” he says at more than one point, invariably acting on his dismay by painting over the day’s work.

When Lord points out that all his acclaim should engender confidence, the unmoved artist shoots back, “What better breeding ground for doubt than success?”

The person closest to Giacometti, the individual who understands him best of all, is his enigmatic brother and collaborator Diego, impeccably played by Shalhoub. “He can only be happy,” he tells Lord, “when he’s desperate and uncomfortable.”

As sitting follows sitting follows sitting — there were 18 in all — Lord increasingly despairs of getting a painting out of a man who feels “it’s impossible to ever finish a portrait.”

In the interim, he finds out more about Giacometti’s life and thought, everything from his fear of banks and contempt for Picasso (“a thief”) to his infatuation with the quicksilver Caroline (Clemence Poesy), a prostitute who has been his mistress for three years.

As much of a character as the flesh-and-blood folks is Giacometti’s classically cluttered studio. Accurately recreated on a London sound stage by production designer James Merifield, it is a marvel of brooding creativity, complete down to specially made copies of Giacometti’s famously elongated sculptures.

Being there becomes a trial for Lord, but our time on the premises, and in the artist’s presence, becomes something to cherish.