This is going to be a big business in the next ten years.

Regretting that tattoo you got? Cheer up: There's a good chance a dermatologist can remove it for you -- but success is going to depend on a number of factors, including how big the tattoo is, what colors it contains and whether you smoke.

Italian researchers who treated 352 people between 1995 and 2010 say they are the first to fully explore the factors that make some tattoos harder to remove than others. Their findings were published online Monday in the Archives of Dermatology.

The doctors used the current standard procedure for tattoo removal, which involves repeated laser treatments spaced several weeks apart. The devices they used, called Q-switched lasers, removed tattoos for 47% of patients in 10 sessions, nearly 75% in 15 sessions.

But success varied. Tattoos were harder to remove if they were:

-- More than 12 inches.

-- Colors other than black or red.

-- More than three years old.

-- On feet or legs.

-- On a smoker. Smoking may impair natural healing processes that help clear ink after treatment, researchers say.

A separate study in the journal looked at a newer laser, not yet approved by the U.S. Food and Drug Administration, and found it removed more than 75% of tattoo ink in an average of four sessions. But the study of the picosecond laser included only 12 patients and did not directly compare it with the standard lasers. It was partially funded by Cynosure, Inc., the manufacturer.

Typical side effects for any laser treatment can include pain, redness and swelling, says Nazanin Saedi, director of laser surgery and cosmetic dermatology at Thomas Jefferson University in Philadelphia. She worked on the study of the picosecond laser when she was a fellow at SkinCare Physicians in Chestnut Hills, Mass.

But it's the cost, in time and money that discourages many peoplewho want their tattoos removed, says George Hruza, clinical professor of dermatology at St. Louis University in Missouri. He says he charges $200 to $600 per laser session, depending on how big and difficult-to-remove a tattoo is. He says doctors are experimenting with several techniques that might speed up a process that can take a year or two and, in extreme cases, "cost as much as car." because treatments typically are spaced a couple months apart.

Still, it's a growing business, Hruza says, thanks to the rising popularity of tattoos and the inevitable regrets among some people who get them. "Some people come in a week after they get the tattoo," he adds.

Maybe it's a good thing that most people seem to like their tattoos: 21% of adults have at least one tattoo and just 14% of those who have them regret them, according to a recent Harris Poll.