When Marvel Comics first launched the character of Black Panther, it was in the July 1966 issue of “Fantastic Four.” As explained in this exclusive clip from the upcoming Disney Plus documentary “Marvel’s Behind the Mask,” premiering Feb. 12, the character of T’Challa, the King of Wakanda, was presented just like any other Marvel superhero — attention wasn’t paid to the color of his skin, but rather to the supreme quality of his abilities.

“The first Black superhero, Black Panther, comes out perfect,” says writer-director Reginald Hudlin, who wrote a run of Black Panther comics in the 2000s. “He’s this cool, elegant, handsome guy who’s just got it on lock.”

But as the clip also demonstrates, there’s one essential element of Black Panther that was glaringly incorrect: His skin is grey, not brown.

“They got so much right, as far as making it just this inevitability that there’d be a Black superhero,” “Behind the Mask” director Michael Jacobs tells Variety. “And yet they still hadn’t caught up yet in, like, just the pure, functional side of making comics. It still wasn’t being produced in a way that represented the rich hue of a true brown color. We see that sort of back and forth along the way, throughout their history, trying to get the lived experience into the comic, but then also realizing the shortcomings of that when it hasn’t been fully worked out yet.”

As initially conceived, “Behind the Mask” was only going to be about the history of Black Panther and T’Challa in Marvel Comics, in anticipation of the release of the feature film “Black Panther.” But as Jacobs and producers Chris Gary and Ryan Simon quickly realized in their research, the full history of Marvel’s efforts to break ground with representation — in race, gender and sexual orientation — was much richer and more complicated than just a single character.

“It became really clear that there was a lot more that Marvel had done as a creator of content to address all the ways that people can be othered or outside of acceptance,” says Gary.

In “Behind the Mask,” for example, we see Marvel guru Stan Lee in his heyday ensuring that background characters in the comics represented the full gamut of racial and ethnic diversity, rather than just a sea of white faces. The comics also included many female heroes, and the relaunch of the X-Men in the 1970s became a clear metaphor for the LGBTQ experience in the U.S.

At the same time, however, Marvel’s first explicitly gay character, Northstar, wasn’t allowed to have a boyfriend for years, and at one point was revealed to be, no joke, part fairy. Many of the early female superheroes weren’t nearly as complex as their male counterparts, and they were often drawn as sexualized objects. And along with coloring Black characters as grey rather than brown, for years Marvel used yellow for the skin tone of its Asian characters.

The latter was an especially shocking discovery for Gary, who is Black and has children of Black and Asian heritage. “I don’t know how I would explain that to my kids,” he says. “That’s a conversation you don’t really want to have, but it’s a necessary conversation.”

Rather than shy away from its less than admirable history, the “Behind the Mask” filmmakers say Marvel’s executives were on board with a warts-and-all look at the company’s efforts with representation. “They were complete partners,” says Gary. “They accepted the fact that we were going to make some things uncomfortable.” The company even opened up its vault so the filmmakers could access the full range of its history.

“There were certain things that we needed to scan that weren’t part of the digital history, that were important to the storytelling,” says Simon. “We needed to get that older imagery out of the vault.”

None of the filmmakers counted themselves as die-hard comic book fans, but the experience of excavating through so much of Marvel’s history left them enormously appreciative for the people who worked to bring so many now-iconic superheroes to life.

“So much of the pop-culture imagination around Marvel is now through the movies,” says Jacobs. “This is a nice reminder that that intellectual property was created a long time ago by some really smart, intelligent people who had amazing ideas and amazing artistry and narrative strength. … They did fall into stereotypes, and they did make mistakes. But there was still something uniquely special about making these comic books and creating these characters.”