"This time around we really wanted Superman to really jump off the screen and have an even more special muster and luminous quality," Wilkinson says, offering a glimpse at Superman's famous red-and-blues as a work in progress.
"The blue of the suit is a little bit more intense and saturated than last time around," he explains, pointing out a newly developed "highly chrome and reflective under suit" that serves as a sort of thin skeleton for the suit.
"When you get the fabric of the suit that is stretched over that," he explains, extending a piece of fabric across the under suit's chest, "you get this wonderful depth and reflection, and it gives the suit a metallic feel."
Ben Affleck's Batman took on a heavy-duty armor for the Justice League finale, but the standard Batsuit received an upgrade of its own.
"We're trying a new material that's super flexible, and we're having a slightly different silhouette, just tweaking all of the lines to make him look super sharp," Wilkinson says of the new cowl, placed alongside the headpiece from Batman v Superman: Dawn of Justice.
"It's built over the Batsuit from the last film," he reveals of Batman's tactical suit. "This time [Batman] has another layer of armor when he realizes he really has to lift his game to fight with the other superheroes and overcome the alien invasion."
"There's no feeling like it," says Superman actor Henry Cavill of stepping into the iconic costume. "It's a special, special thing to put the Superman suit on, and I get excited about it still. Me and my friends we talk about it, we geek out about Superman. It's truly, truly unique."
Wilkinson, who worked with original Justice League director Zack Snyder on 300, Watchmen and Sucker Punch, provided the costume design for Man of Steel and Batman v Superman. Wilkinson is seen pitching updated Batman suits to Snyder in the behind-the-scenes video above.
Justice League is now available to own on Digital HD and releases to 4K Ultra HD Blu-ray and Blu-ray March 13.