New Year’s Day now doubles as Public Domain Day, when a fresh trove of vintage artistic creations becomes available each year for anyone to use, adapt and exploit as copyrights expire. And at least emblematically, the big game this year is the first cinematic iterations of Mickey Mouse - the poster rodent for extended copyright protections.

To be clear, for most this is not even your father’s Mickey and Minnie Mouse who are entering the grab-bag marketplace of adaptation Monday. The public has gained the right to creatively use the breakout black-and-white Disney characters strictly as they appear in the 1928 animated short film “Steamboat Willie,” as well as that year’s silent version of the short film “Plane Crazy.”

This co-optable version of rascally Mickey is described by some scholars as “rat-like” and lacking his well-known, polished look and garb. Yet this early Mickey, as rendered by Walt Disney and Ub Iwerks during the Jazz Age, is all yours: No gloves, no shirt - full service.

Jennifer Jenkins, a law professor and director of Duke University’s Center for the Study of the Public Domain, says that from a copyright angle - trademark considerations are a different matter - “You can use Mickey and Minnie 1.0 from ‘Steamboat Willie’ and ‘Plane Crazy,’ but you cannot use the aggregated later Mickey that, for example, appears in one of my favorite films, ‘Fantasia.’ You cannot use the copyrightable aspect of the character from later, still-in-copyright works.”

So why the big deal, then, if you can’t adapt the character as most people recognize him? Creatively speaking, isn’t this making a Matterhorn out of a molehill?

Actually, any Mickey entering in the public domain is meaningful for several reasons, experts say.

“When Mickey first appeared in ‘Steamboat Willie,’ it was a game changer,” says Joe Wos, a cartoon historian and the Emmy-winning host of PBS’s “Cartoon Academy.” It was “one of the first sound cartoons, with Walt himself providing Mickey’s sounds. What set ‘Steamboat Willie’ apart was the emotional storytelling.”

Mickey, who pilots a steamboat in the animated short, “was an Everyman character” modeled at least partly on Charlie Chaplin. “Audiences identified with his joys and frustrations. He appealed to all ages,” Wos says. “He also assured the success of Disney’s studio. In order to hang onto its cash cow - er, mouse - Disney fought to extend copyright laws.”

Disney wasn’t the only driver behind successful legal efforts in the 1970s and ‘90s to extend copyright protections, resulting in such characters as Mickey being safeguarded for nearly a century. Many companies lobbied to protect intellectual property rights when successfully lobbying for the 1998 Copyright Extension Act, which protected many artistic works for an additional 20 years. Yet unfairly, some scholars say, it was derisively dubbed the Mickey Mouse Protection Act.

“All the movie studios wanted [that act],” says Zvi S. Rosen, a Southern Illinois University School of Law assistant professor. He notes, too, that the Sonny Bono Copyright Term Extension Act - its official name - also prominently protected songs composed by George and Ira Gershwin. And Disney was part of a larger coalition that lobbied for copyright extension in 1976, he says.

Yet Mickey Mouse’s iconic status - and considerable value - made him the face of efforts to extend and protect copyrighted material, if for little reason beyond being even more broadly recognizable than Jazz Age authors and composers.

Disney also has a reputation for its intense legal vigilance when it comes to protecting its properties - what Wos calls “an ironic twist for Disney, which built their empire on public-domain fairy tales” such as Cinderella and Sleeping Beauty. Jenkins calls that dynamic the “love triangle” among Disney, its Mickey protection efforts and its savviness with adapting nonprotected works.

So what lies ahead legally for Mickey and Minnie? That’s difficult to predict, experts say, while noting that in recent years, Disney has offered the full “Steamboat Willie” short free for public viewing and featured the character prominently alongside the company logo.

“Ever since Mickey Mouse’s first appearance in the 1928 short film ‘Steamboat Willie,’ people have associated the character with Disney’s stories, experiences and authentic products. That will not change when the copyright in the ‘Steamboat Willie’ film expires,” the Walt Disney Co. told The Washington Post in a statement. The more “modern versions of Mickey will remain unaffected by the expiration of the ‘Steamboat Willie’ copyright, and Mickey will continue to play a leading role as a global ambassador for the Walt Disney Company in our storytelling, theme park attractions and merchandise.”

Disney notes that it won’t stand down completely: “We will, of course, continue to protect our rights in the more modern versions of Mickey Mouse and other works that remain subject to copyright, and we will work to safeguard against consumer confusion caused by unauthorized uses of Mickey and our other iconic characters.”

One potential bellwether is the early iteration of Winnie-the-Pooh - before creator A.A. Milne’s work was adapted by Disney - which entered the public domain two years ago. (Worth noting: Winnie’s Hundred Acre Wood sidekick Tigger also entered the public domain on Jan. 1, alongside silent films like Buster Keaton’s “The Cameraman” and Laurel and Hardy’s comic debut as a duo “Should Married Men Go Home?” as well as the song “Let’s Do It (Let’s Fall in Love)“ by Cole Porter and such literary works as “Orlando,” “Lady Chatterley’s Lover,” “The Threepenny Opera” and “Home to Harlem.”)

Nothing created with Public Domain Pooh since 2021 has altered popular perceptions of the original property, says Jenkins, while noting that such one-offs as a climate-change Pooh parody featuring deforestation in the Hundred Acre Wood attracted some attention, as did the “Winnie the Pooh: Blood and Honey” slasher flick that has grossed nearly $5 million. (In a similar vein, Rosen points out that a trailer has been released for a planned shooter game inspired by the look of “Steamboat Willie.”)

So what might be fair game for those looking to adapt Legal Mickey, who still bears more than a little resemblance to present-day Mickey?

Take Mickey’s early dance style, which is jaunty and “a little more awkward,” vs. his later fluid moves, Jenkins says. “These are the kinds of generic character traits that are not subject to copyright protection. These are isolated, uncopyrightable features of later iterations.”

Also not eligible for copyright, she says, is simply having your anthropomorphic mouse character talking in a high, squeaky voice: “What do you think it is going to sound like - Barry White?”

Jenkins notes that two iterations of Mickey are entering the public domain because of how different the “Steamboat Willie” Mickey looks from the “Plane Crazy” Mickey: The latter “has, these big eyes covering half of his face.”

Jenkins urges would-be Mickey adapters to follow some general guidelines.

“Do exactly what copyright expiration allows you to do and make something awesome with public domain Mickey and Minnie. . . . Just don’t do it in a way that confuses consumers. And don’t do it in a way that uses later copyrightable elements of copyrighted iterations of the characters.” Stay in the zone of what “trademark and copyright law allow you to do.”

“Don’t start selling your Mickey Mouse merchandise and don’t make a cartoon and mislead the public into thinking it’s a Disney production,” she advises.

Otherwise, she says: “Start your creative engines.”