The Melbourne leg recently drew more than 10,000 people, with almost 300 tattoo artists plying their trade.

Ms Yu says that interest in tattooing continues to grow.

“I don’t think it’s a fad,” she says. “I’ve worked on these shows for three years. They’ve just gotten bigger and the hype around it hasn’t dropped.”

Approximately one in seven Australians have at least one tattoo, according to a study conducted by social researchers McCrindle. Slightly more men than women have one, and while a number of people reported getting tattoos when they were younger, 40 per cent got their first tattoo when they were 26 or older. In fact, one in 10 Australians got their first tattoo in their mid-40s or older.

The Melbourne expo also featured live performances from local musicians Celeste Newman and Adam Rigley, as well as by the UK fire and acrobatic group Pyrohex. The expo also incorporated a “Girls of Ink” pageant, a pin-up fashion pageant, and several competitions for the best tattoos that were inked during the event.

1. Pick a style, any style

There are a number of different styles of tattooing, just as there are several movements that we associate with specific art styles.

Most people are familiar with the traditional style of tattooing –  ships, anchors, hearts and pin-up girls with bold lines that hark back to the early 20th century when tattoos adorned the skin of criminals and American sailors. Traditional (also referred to as American traditional or “old school”) is the oldest tattooing style in the Western world.

Polynesian tattoos, which involve black-and-grey line work, scarification and face tattoos, came much earlier than traditional American tattoos. Japanese tattoos date back to 10,000BCE, with images of colourful dragons, cherry blossoms, koi fish and lotus flowers covering the entire back and arms.

Chantelle Thong, who has been a tattoo artist for seven years, specialises in black-and-grey realism and surrealism portraits.

“It’s a little bit mysterious,” she says. “I just find myself designing morph images, so blending all different images together and creating the one piece. I like tattooing a lot of faces.”

In the past couple of years, she’s noticed that a lot of women have become interested in lines and dots because “they’re softer, feminine pieces.” She also thinks mandalas are popular – large patterns dominated by squares or triangles. The word “mandala” comes from the Sanskrit word for “circle” and is characterised by its concentric structure.

Ms Yu says black-and-grey realism is trending.

“A lot of people like to get portraits of their pets or family members. When you get someone that can replicate a photo, it’s pretty cool.”

She also says that lettering is popular, and a lot of script tattoo artists are doing well.

Jesse Smith, who headlined the expo, is from the US state of Virginia and has been tattooing for 19 years. He featured on the reality tattoo series Ink Master. Unlike most tattoo artists, Mr Smith isn’t heavily tattooed, and most of his tattoos aren’t visible.

He doesn’t subscribe to a particular style of tattooing.

“It’s cartoon-y and it’s got a little bit of graffiti influence,” he says. Some people refer to cartoon styles as “new school”.

But Ian Mercer, who works for tattoo supply company Tatsup, says that while tattooists might stick to a certain style, they will always employ a personal touch.

“It’s their take on the particular style, so that’s why tattoos can be so unique.”

2. Don’t try this at home, kids

The “stick and poke” tattoo has also gained attention. You can purchase a DIY stick and poke tattoo kit online for $US44 (about $A58) to tattoo yourself or your friends at home. The kit comes with a few needles, ink, gauze and instructions, along with a few simple designs.

Modern tattooing is done with electric machines, which inserts the ink pigment with a needle into the dermal tissue lying underneath the epidermis, or surface layer of skin. The needle on a machine is driven in and out of the skin anywhere between 80 to 150 times a second.

With a “stick and poke” tattoo, everything is done by hand, so the process is effectively a slow stabbing into the skin after the needle has been doused with ink.

Thus, the effect is similar to something you would get in prison – wonky lines, amateur designs . . . and maybe an infection.

“I can’t hate on it too much because that’s how I started,” says Mr Smith, who was in the US army, where he met a man called Carlos, who had just got out of prison.

“He was doing tattoos out of his house with a ghetto gun and we would just hang out and draw all the time. One day, he was like, ‘Hey, do you want to do a tattoo?’ ”

Mr Smith only planned to ink one tattoo, but soon had people lining up at his door.

“It wasn’t because I was good,” he adds. “My tattoos were horrible back then. [The queue] was more because they were free.”

Chantelle Thong is not a fan of “stick and poke”.

“I don’t think anybody who doesn’t have experience should be tattooing anybody. I think people don’t take it seriously enough. They do last forever, and there’s so much you need to know about sterilisation,” she says.

Mr Mercer agrees. He delivers supplies to tattoo shops in Melbourne daily, and thinks the tattoo industry has some of the most hygienic workplaces in the world.

“It’s a very high level of sanitation, so when people go, ‘Oh, tattoos are dirty’ . . . No, you’re an idiot. You have no idea what these [tattooists] actually go through on a daily basis.”

Tattoo artists commonly use autoclaves – pressurised steam machines that destroy micro-organisms – to sterilise their tools. They’ll also purchase tattoo needles that have been pre-sterilised and individually wrapped in blister packs. Supplies are constantly re-stocked because new needles are always used on clients. Gloves are also an essential.

“If I was going to do it all over again, I would have gone through an apprenticeship,” Mr Smith says, lamenting his early tattooing experiences. “You don’t really know what you’re doing. You can infect yourself and you can infect your friends. So now, knowing what I know, I would never do that again.”

3. The times, they are a-changin’  

The tattoo industry is constantly evolving. Tattoo artists and their styles have become much more recognisable through Instagram.

“I think Instagram has done leaps and bounds for any business,” Melissa Yu says. “If you market it right and take some good photos, it definitely does help.”

“There were a lot fewer people getting large work. Nowadays, everybody has big stuff – they get full sleeves. If I did a half-sleeve back in the day, I was stoked.” — US tattoo artist Jesse Smith

She says that people increasingly are getting laser tattoo removal so they can have more clear skin available to get tattooed.

“It’s a rising industry, so naturally everything is going to expand in that way, including laser tattoo removal, but you also look at cosmetic tattooing [eyebrows, lips, eyeliner], scarification, piercings – that’s expanded too. It’s a ripple effect.”

Tattoos are also considered less of a taboo, according to Ms Yu, who was “clean-skinned” before she met her heavily-tattooed partner. His death a couple of years ago has made her more passionate about tattoos.

“Social values change, thank goodness,” she says. “It’s shifted. I think the more people do it and the more exposure there is, the more common and accepting it is.”

The quality of artwork continues to improve, too, according to Ms Thong.

“Five years ago, portraits were being done but they weren’t being done as amazingly,” she says. “Now it’s just a whole different level. So, I think 10 years from now, it’ll be that again.”

Ms Thong adds that the tattoo world used to be a bit of a “boys club” and that being a female in the industry was difficult.

“A lot of guys didn’t take me seriously, but that’s so much better now,” she says. “There’s so many amazing female artists that have made a name for themselves. But I think that happens with a lot of jobs. It’s not just tattooing.”

Mr Mercer from Tatsup says the technology in tattooing is evolving daily.

“Whether it comes to machines, power supplies, what goes into inks, the aftercare products . . .  there’s always a new product coming out,” he says. “It’s a hard one to keep up with, that’s for sure.”

It was recently reported that one in five tattoo inks contain carcinogenic chemicals, prompting widespread debate about tattoo safety.

“I would like to know what inks they were testing because if they just jumped on eBay and tested a whole bunch of random backyard inks, then of course there’s going to be stuff in it that there shouldn’t be,” says Mr Mercer, who adds that Tatsup stocks “world-class brands”, some of which have been created by tattooists or people who have been in the industry for a long time.

4. When I grow up, I want to be a tattoo artist

There are no formal training courses or a tattoo school that you can attend if your aim is to become a tattoo artist. Usually, budding tattooists start by finding an artist who will offer them an apprenticeship.

Ms Thong became fascinated with the tattoo world through her father, who started getting tattoos when she was five years old. She’d always wanted to do something in art, and decided when she was 12 that her focus would be tattoo art. She got an apprenticeship when she was 16, simply by approaching local tattoo parlours and asking for experience.

The Australian Tattooists Guild is working to create guidelines to standardise the apprenticeship system. They recommend that trainee tattooists get accredited in a cross-contamination course to learn about sterilising equipment and procedures, and do some form of art training.

Mr Smith says that when he started, only a handful of tattooists had undertaken formal art training.

“Since then, every other person in the tattoo world has been to art school or has done other forms of art outside of tattooing,” he says.

The next step for trainees is to build a portfolio of “flash” designs for tattooing on people. Variety is important, and competition dictates that designs should allow the artist to demonstrate their own particular style.

After that, their best bet is to approach established tattooists for an apprenticeship. Two to four years is considered a decent length of an apprenticeship.

Once established, tattooists need to guard against imitators.

Ms Yu says plagiarism is definitely a problem for the industry.

“If you’re an artist, you want to inspire others but you want them to do their own thing,” she says. “No artist would ever replicate someone else’s work if they were truly an artist.”

5. Tattooing is addictive (for some)

Slightly more than one in two tattooed people have a single tattoo, according to statistics; 23 per cent have two to three, while 15 per cent have five or more.

Mr Smith thinks getting tattoos can be addictive.

“I know as soon as I got tattooed, I was ready for my next one, for sure,” he adds.

“I think it’s addictive in the sense that they’re fun and it’s creative and you meet a lot of cool, different artists that you can start getting tattoos off,” she says. “I don’t get an adrenaline rush – they hurt! But everyone’s got their vice. If some people like the pain, then they’ll go for more.” — Melissa Yu, Australian International Tattoo Expo

He has also noticed that more and more people are getting bigger tattoos, compared to when he started in the trade.

“There were a lot fewer people getting large work. Nowadays, everybody has big stuff – they get full sleeves. If I did a half-sleeve back in the day, I was stoked,” he says.

It’s an expensive habit. The cost will depend on the size and amount of detail that goes into a tattoo. Ms Thong and Mr Smith charge according to the time spent on a tattoo.

“It’s usually about $1200 a day,” Ms Thong says. “Everything I do is quite large-scale, so we get a lot done in a session and we sit for a while.” A session can range from five to eight hours. Mr Smith’s minimum for a half-day session is $1000, and $2000 for a full day.

Ms Yu says she isn’t addicted to tattoos, although she understands the attraction.

“I think it’s addictive in the sense that they’re fun and it’s creative and you meet a lot of cool, different artists that you can start getting tattoos off,” she says. “I don’t get an adrenaline rush – they hurt! But everyone’s got their vice. If some people like the pain, then they’ll go for more.”