Colleen Harris doesn't fit the stereotype of the buttoned-up librarian.

Her arms are covered with a pirate queen motif and black scrolling tattoos, which extend down the side of her body to her ankle. A black rose and the words "Dangerous Magic" adorn the back of her left hand, and the words "Anam Cara" (old Gaelic for "soul friend") letter her knuckles.

The 27-year-old — who has multiple masters degrees and a job at the University of Kentucky's research library — feels no pressure to cover up.

"It's not really possible at this point, unless I wore gloves," Harris said, adding that she thinks academia has been more accepting of her body art than the corporate world would be. "I think my qualifications should speak for themselves."

The face of the young American worker is changing, and it's increasingly decorated with ink and metal. About half of people in their 20s have either a tattoo or a body piercing other than traditional earrings, according to a study published in June in the Journal of the American Academy of Dermatology. That figure, which is higher than the national average, is growing, said Anne Laumann, the study's co-author and a dermatologist at Northwestern University.

As a result, employers are finding that dress codes may need updating. In some cases, bosses are loosening up to attract young talent. In others, managers are adding new rules to keep body art covered up.

"In the past, there were very general dress codes. Now, I see dress codes that are five pages long," said David Barron, an attorney with Epstein Becker Green Wickliff & Hall PC. "Employers see a need to be very, very specific, and draw lines very clearly."

At the medication flavoring company Flavorx - where the average employee is about 28 years old - chief financial officer Woodie Neiss recently told human resources to add a body art section to the dress code, after an employee showed up to work with an eyebrow piercing.

A sizable portion of his 40 employees have body art, Neiss said. He knows it because he's seen them show it off to each other in the office.

"Do whatever you want to your body, but I don't want to be subjected to it in the workplace," Neiss said. He added that body art can be a distraction, and especially important to hide when investors visit the office.

Usually, it's a simple matter of discussion and compromise. Most piercings are on the face, according to the recent study, but they can be removed. Only about 15 percent of people with tattoos have them on their face, neck or hands, the study showed, so the rest can be covered by clothing.

Michael Sacks, 24, who works at the public relations firm SheaHedges Group in McLean, Va., has three tattoos: on his stomach, the initials of a friend who died; on his back, the word "Persistence"; and on his ankle, his fraternity letters, Phi Gamma Delta. None can be seen when he's wearing his work clothes, and he says that's intentional.

"It's a visibility issue. No one cares what you have on your body as long as you don't have to look at it," Sacks said. "I want to be perceived as a professional."

It all depends on the industry. Harris, the librarian, worked in corporate technology sales before her library science degrees and tattoos. Her only visible body art was a nose stud, but she voluntarily removed it while at work.

"It's a matter of catering to your clientele, no matter where you are," she said.

For some companies, allowing body art can be a boon - it attracts young workers that may not feel welcome in more conservative environments, said Paul Forster, CEO of the job search Web site Indeed.com (which shows that postings for tattoo artist have surged in the past year). Forster allows body art in the office, and about a quarter of his 25 employees have it.

"Most work is done via e-mail, instant message, over the phone. We don't have those face-to-face issues," Forster said.

Of course, at workplaces like design firms, salons, and retailers targeting the young demographic, hiring employees with body art is par for the course. Joe Duffy - CEO of the design firm Duffy & Partners, which has developed branding for companies including Coca-Cola (KO), BMW and Starbucks (SBUX) - said he hired a young woman about a year ago who used her tattoos as part of her application portfolio.

But in traditionally suit-and-tie service industries, bosses want body art hidden, according to Talar Herculian, an employment attorney with Fisher & Phillips LLP in Irvine, Calif. - and that means going about restricting it legally. More employers err on the side of being too vague about their dress code rather than too strict, she said, and that's when problems emerge.

"Most people who don't have counsel don't realize what their rights are. They're afraid to impose restrictions. You can be very stringent," Herculian said. If a dress code is put into writing and doesn't discriminate between the sexes, it can be enforced legally, as long as employers are open to negotiating compromises for health or religious reasons.

The major U.S. lawsuit regarding body piercings - Costco Wholesale Corp. (COST) versus an employee who was a member of the Church of Body Modification - found in favor of the employer. Still, Barron said, it's important to note that the decision wasn't an automatic one; the courts will weigh the burden of the employee against the burden of the employer.

"Old stereotypes are being challenged. What seemed very accepted 10 years ago may not be now," Barron said. "A lot of younger folks are entering the work force. The standards that have been in place are going to be pushed, and usually the way they're pushed is through lawsuits."

Will there be a point when bosses don't bat an eye at their employees' body art?

"We're probably another 10 years away from that. You have to wait until these guys and girls are managers themselves," Flavorx's Neiss said. "If you're a suit-and-tie kind of place, I don't think it'll ever be appropriate there."

In some sectors, though, the shift may already be happening: SheaHedges' Sacks said that a few months ago at an interview with what he describes as a "quirky" PR firm in Minneapolis, the topic of tattoos arose. The interviewer stood up, lifted her leg on her desk, and pulled up her pant leg to show him the big butterfly tattoo on her calf.