South Korean tattooists on Friday slammed a "pathetic" decision by the country's Constitutional Court that upheld a ban on the practice by non-medical professionals.
While tattooing itself is not illegal in South Korea, it is classed as a medical procedure and only a doctor may carry it out.
Under the decades-old law, violators can face up to two years in prison or 10 million won (US$8,200) in fines -- although prosecutions are rare.
A group of South Korean tattoo artists had challenged the law, but on Thursday the court dismissed their petition, citing the risk of "health-related side effects".
"No one in the world believes that tattooing is a medical practice and requires medical expertise... What we do is art," renowned tattooist Kim Do-yoon -- whose clients include Brad Pitt and members of K-Pop band EXO -- told AFP.
"It's just pathetic because only the judges of the Constitutional Court don't seem to know this," added Kim, who heads a union of 650 tattoo artists.
Kim is facing prosecution under the law after he was filmed tattooing a famous South Korean actress, and he vowed to fight it with all legal means at his disposal.
"I want to be acquitted by the Supreme Court of Korea," he said, adding this would "set a meaningful legal precedent."
The ongoing ban reflects tattoos' long-marginalized status in South Korea, where they were once associated almost exclusively with organized crime.
The court said it was up to the country's legislature as to whether to introduce a new license program for non-medically qualified tattooists.
"Even if some unlicensed medical practitioners have special ability to perform medical practice without side effects, it is virtually impossible to distinguish them," the judges said.
According to the Korea Tattoo Association, at least a million people have inked their skin in the country and the illicit but growing industry is worth about 200 billion won ($170 million) a year.
It says another 200,000 beauticians who apply permanent makeup to their clients using tattooing techniques also come under the current rules.