Fans become obsessed with their favorite TV shows and films, so much so that a hit can nudge the world of fashion. On the other hand, current fashion designers can influence the look of a TV series even if that means straying from a strictly period look.

That give-and-take between costume and fashion design plays out in some of this year’s Emmy contenders.

With a show that began with the sinking of the Titanic and has now moved past World War I, “Downton Abbey’s” costumes have modernized quite a bit — for some — which gives designer Caroline McCall some freedom in her designs. For traditionalist characters such as Carson the butler and Lord Grantham, costumes remain much the same.

The characters’ costumes are such a hit that PBS has launched a jewelry line with designs inspired by the women’s wear. From estate bracelets to hair pins, the line has fans covered for their fanciest occasions. But McCall thinks that “The Great Gatsby” and “Boardwalk Empire” are also responsible for the resurgence in estate jewelry.

Mad Men” costume designer Janie Bryant knows that while living up to the fashion expectations that comes with the Madison Avenue address is important, she tends to focus her efforts on having the characters remain realistic.

“It really is about telling the story of the character through the costume design. There are definitely fashionable characters but really the most important thing to me is that the characters are true to themselves,” Bryant says.

Although she focuses on the characters’ complexities to design their costumes, Bryant will include staple 1970s fashions such as psychedelic prints and bell bottoms.

“Game of Thrones” costume designer Michele Clapton has to plan for everything from winter to summer, from royals to near-savage “wildlings.” That can create some difficulty.

“The hardest part is the most fun part,” Clapton says. “It’s to try and be original in thought without any aid from a fixed period in history.”

But set locations, architecture and script help guide Clapton in her designs. She turns to certain designers such as John Galliano and Hussein Chalayan for inspiration, but it’s a two-way street.

“I believe from others that the costumes have inspired certain designers, not sure if it was specifically the costumes or maybe the whole mood of the show,” Clapton says. “Who knows!”