It may seem odd, when talking about a director only two films into his career, to describe “The Invisible Woman” as “a very Ralph Fiennes film.” By his own admission, the twice Oscar-nominated actor has yet to forge a recurring directorial stamp; both his films exude the confident curiosity of an artist open to any number of ideas and influences.

Yet if the restrained elegancy and disciplined sexuality of “The Invisible Woman” — a delicate, melancholic costume drama about Nelly Ternan, the historically sidelined mistress of Charles Dickens — seems natural coming from Fiennes, that’s largely because they match his refined, precise qualities as an actor. Those, too, are on display in the film: Fiennes plays Dickens to Felicity Jones’s Ternan, and the two have a quiet but urgent chemistry that makes for one of the year’s most unexpectedly moving screen romances. Though adapted by Emmy-winning screenwriter Abi Morgan (“The Hour,” “The Iron Lady”) from a 1991 biography by Claire Tomalin, the relationship at the film’s center is still far from common knowledge; Fiennes’s film illuminates it with considerable grace.

“I wasn’t a Dickens buff at all going into the project,” he admits. “I had only read ‘Little Dorrit,’ and obviously seen the David Lean adaptations and so on. But I’m glad I wasn’t: the combination of Abi”s screenplay and Claire”s book was like switching on a light. But the thing that led me wasn’t Dickens, but Nelly. It was the story of a woman who had not, or could not, come to terms with a past love that haunts her. That’s the element in the screenplay I loved and wanted to strengthen.”

The script came Fiennes’s way as he was seeking a directorial project to follow up his 2011 debut, a resourcefully modernized yet classically performed adaptation of Shakespeare’s war tragedy “Coriolanus” that earned him the immediate attention of critics — but left him creatively restless. “There was so much I needed to learn, things I had sort of messed up, technical and otherwise, and I was very keen to get back into it,” he says. “I didn”t know what the next one would be, and didn’t for a second think it would be a Victorian drama. But this piece just got under my skin. I couldn”t let go of it.”

Though Fiennes has a natural aptitude, like many actors moving into directing, for “nurturing and exploring” performance, he’s most excited by the possibilities of the camera itself, and saw “The Invisible Woman” as posing fresh challenges in that department. “Photographically, I had chosen a high-intensity way of shooting on ‘Coriolanus,'” he says,”but what I most enjoyed was finding the strong frame of the camera-observed face.”

He cites his work with the Hungarian director Istvan Szabo on the 2000 film “Sunshine” as having particularly inspired him in this department. “I like that classicism, that stillness,” he explains. “There”s one scene in ‘Coriolanus ‘ where Jessica Chastain approaches the bed and and is partly masked by my profile; these two faces come together as one and there”s a moment of tension, something unsaid. It was so well executed by Barry Ackroyd: a complete moment, all the information held within the frame. I wanted to explore that more in the way we shot ‘The Invisible Woman.'”

Working this time with up-and-coming cinematographer Rob Hardy (“Red Riding,” “Broken”), Fiennes incorporated a range of influences into the new film’s serene aesthetic; I observe that many shots in the film seem to echo the lighting and composition of 19th-century English painters, though he adds that more contemporary references came into play: “There’s an American photographer we both admire called Saul Leiter who observes from behind glass or through doorways; he has a lot of shadow and masking in shots, so the eye goes to one particular part of the frame. Rob’s composition is very exciting to me, his decisions over where to put the camera.”

Fiennes still sees filmmaking as a learning curve — “I still feel I miss stuff, and wish I’d gotten shots ofthis or that” — but does believe he’s improved over the course of his sophomore feature: “My technical awareness is sharper, my timing, my sense of letting moments play out before you without cutting too early. I”m still learning so much, but I think I was more confident in communicating with people, sharing the fact that I didn”t know how to solve a problem. The first time around I was so adrenalized and so crazy: I learned a lot in the editing about framing, camera, eye, face, the information you”re getting.”

He credits Nicolas Gaster, his editor on both films, for teaching him about how shots read, and what translates to a strong performance on camera: “I”ve had to sit with Nick for so many hours, challenging the coverage on myself and seeing what”s working and what isn’t. It”s kind of painful and peculiar to sort of put footage of yourself through that process: that”s shit, that”s shit, that might be okay, that”s okay, that”s the best one, the rest is shit. It’s good for you in the way that a cold shower is good for you.”

After taking the title role to forceful effect in “Coriolanus,” Fiennes admits that he was reluctant to star in his own film again. “It”s difficult because you have to go from one headspace to another, while looking after other actors and making choices about their performances, camera moves and everything, and then then suddenly be immersed in Charles Dickens,” he explains.

“I think it”s possible to have your part in reserve and then go and play it. But what makes it hard is the time pressure. You need time to find it, be it and then pursue it,” he continues. “And sometimes it’s the end of the day and the clock is ticking, and if you had just three or four more takes you could have gone into it deeper.”

He initially approached another actor to play Dickens and relieve him of that pressure, but when it didn’t work out, he gave in to his colleagues’ insistence that he take the role himself. “Ultimately, I”m an actor,” he says. “If there”s a role that smells good, it”s hard to resist it. I was working on the screenplay with Abi and reading all the parts, and as we teased other nuances of dialogue and rhythms, she and Claired kept saying I should play him. So in the end, I just said, ‘Fuck it.’ I could see from the first draft that it was a great role: he’s a brilliant, complicated, contrary man.”

Still, he’s less interested in his own performance than that of Felicity Jones as Nelly; reined-in, fragile, playing the character from her teens to early middle age,the young British actress does indeed deliver the most complex work of her career thus far. “She”s amazing,” he raves. “I wanted someone who could inhabit an older Nelly without makeup and stuff, simply through her acting. She can inhabit an interior landscape in a way that”s really mesmerizing and the camera really is drawn. The camera likes her, obviously, but she can write emotion and thought on her face — that”s a great filmmaker gift she has.”

I remark that she has the gift similar to that demonstrated by Abbie Cornish in “Bright Star” — the ability to project contemporary youth and sexuality within the appropriate period register. He agrees, and says that was his intent for the entire film: “I wanted people to be people, for all the bonnets and crinolines and frock coats,” he says, “and Felicity is brilliant in that kind of naturalism. The clothes are the clothes and the sets are the sets, but they’re not the human truth. Social mores and behavior and language may be a little different, but essential, human behavior is not.”

“What was so very moving about the research and reading of Dickens and Nelly and Wilkie Collins was the sensethat these people had fun and parties and mistresses and desires. The way we receive the Victorian Era through history books, people are always posing stiffly in black and white. Actually, looking at paintings is much more informative – the energy and the color and the brightness of their lives comes through, and I could make the imaginative connection between us and them. That’s what I wanted the film to get: the perspiration under the crinolines.”

After having worn both hats, is it difficult to return simply to acting in another director’s project? “I think it’s a bit of a relief, actually,” he says, “if the director really knows what he or she wants. But once you’ve had the experience making choices from behind the camera, if you sense something”s not quite right, you can”t help but have an opinion about a camera position or lens or something. And you feelyourself getting twitchy to direct again. Then again, when you’re working with Wes Anderson in Germany, it’s a pleasure simply to act.”

The Wes Anderson film in question, of course, is “The Grand Budapest Hotel,” which opens the Berlin Film Festival in February — Fiennes plays the central role in the all-star ensemble comedy, and describes the project with palpable affection: “This script is fantastic, so very funny, and Wes is a very lovely presence to be with,” he enthuses. “He”s very encouraging, everyone’s treated very equally, there’s just a happy atmosphere around him. And of course, there are all those great actors: Harvey Keitel, Edward Norton, Jeff Goldblum, Jude Law, Saoirse Ronan, Tilda Swinton. The sense of being so collective, in such a strong company — it’s great.”

He is, meanwhile, already on the lookout for his third directorial project, and after having taken on Shakespeare and Dickens from different angles, he admits he’d like to “move away from the literary route” and take on more contemporary material — “Something very immediate and now, though I don’t know what it is yet,” he admits. One thing, he says, is a given: “I don’t want to be in the next one, for sure. If I’m lucky enough to find something.”

“The Invisible Woman” opens in limited release on Christmas Day.