A tattoo used to be a sign of defiance or membership of a group, most commonly seen on sailors, bikies or criminals — like the Japanese Yakuza.

But in recent years the development of bolder and brighter colours has given the tattoo a whole new openness and popularity.

It's estimated that around 40 percent of people aged 18-35 have at least one tattoo, and many have significantly more.

Tattoos are no longer secret adornments. More often than not, they're a way of expressing individual identity, a part of personal "branding".

They're also pieces of intellectual property. And as their popularity increases, says lawyer Shontavia Johnson from Drake University in the US, so too do the arguments over ownership.

"If I have a personal brand and my brand includes the display of tattoos, I feel not only a personal connection, but really some amount of ownership in that thing," she said.

But just because you paid for the ink and your skin is the canvas, doesn't mean you are the only one who feels a sense of pride in that artwork.

"A tattoo artist is a creator, just like a musician or an actor or a filmmaker. That tattoo artist, along those same lines, is creating art, creating a body of work," she said.

High-profile lawsuits

Rasheed Wallace was involved in a lawsuit over a Nike advertisement showing the Egyptian-themed tattoo on his right arm. ( Getty Images )

One of the first notable lawsuits involved a basketball player named Rasheed Wallace, who appeared in a television advertisement for the sportswear company Nike.

"They show the tattoo and the tattoo is being digitally recreated on Rasheed Wallace's arm, and Rasheed Wallace is explaining why this tattoo is important to him and what it means," Professor Johnson said.

"Shortly thereafter the tattoo artist filed a lawsuit suing this basketball player and the Nike organisation.

"It was probably very surprising for Rasheed Wallace to learn that someone else said they owned his tattoo."

Another highly publicised case in 2011 involved the tattoo artist who designed ex-boxer Mike Tyson's distinctive facial tattoo.

He received a settlement payment from the company Warner Brothers Entertainment after they replicated his artwork on an actor in one of their films.

Other recent lawsuits have involved the US athletes Kobe Bryant and Lebron James.

Tattoos as a form of art

Given the intricacy and artistry of many modern tattoos, Professor Johnson said it was hardly surprising there had been a rise in ink-related litigation.

She said it was clear many of them fell within the parameters of definable art under standard copyright provisions.

"It has to be something original; something that falls within a framework that we understand, so something that is a work of authorship or a work of creativity; and it also has to be something that we can feel, see, hear or perceive in some way," she said.

"If those three things are met, then really you probably have a copyright in that specific thing from the standpoint of ownership of a tattoo or any other piece of art."

Most of the lawsuits Professor Johnson has researched involve celebrities or athletes, but things are changing.

"We now have these internet sensations, these internet celebrities, who have a platform sometimes much greater even than traditional celebrities," she said.

Get it in writing, not just in ink

Copying someone else's distinctive artwork or committing a trademark violation — where a person has a company's logo inked onto their body without approval — could also result in legal trouble.

Professor Johnson said she had never heard of a situation where a judge has ordered the physical removal of a tattoo. Most disputes are resolved before the need for court intervention.

"Oftentimes when there is a lawsuit, they settle very quickly because the tattoo artist a lot of times doesn't have much to lose. They are very, very interested in getting justice," she said.

"But we do have a lot of settlement talks, a lot of negotiations where people are trying to figure out how to agree in this particular capacity."

Her advice for anyone thinking of getting a tattoo in this modern litigious world?

"Get a release very early. Get a contract signed between you as the tattooed individual and the tattoo artist," she said.

"That is one of the best things an individual can do if they find themselves running afoul of some copyright-related claim, some type of contract."

And here's another tip: if you are going to copy someone else's body art, make sure it doesn't involve a member of the Yakuza, or Japanese mafia — that could be problematic for other reasons.