Along a bare torso and down a thigh, the sun glints through ocean waters and bathes coral and fish in aqueous light. On a lower leg, vivid frogs tense, as if preparing to jump from dewy leaves. A mischievous child with twinkling blue eyes stares out from an inner bicep.

In his home studio in the northern Italian village of Grado, Alex De Pase reviewed photographs of some of the thousands of designs he had inked over his career as a tattoo artist. But these skinscapes might not be possible to replicate in 2023 — at least not with the same set of colors.

New regulations on tattoo inks and permanent makeup that began taking effect across the European Union in January were meant to reduce the risk of including ingredients that could be health hazards. The regulations have also caused the biggest shake-up of the industry in memory, with ink manufacturers reformulating entire product lines to comply.

The possibility of even more disruption hangs over artists’ heads next year, when bans go into effect on green and blue pigments that ink manufacturers say may be impossible to replace. This has provoked an uproar among tattooists who have argued the restrictions are overbroad, sow unnecessary concern among clients and undermine their art.

Europe’s regulations could portend changes in the United States, where the Food and Drug Administration has some oversight of inks and pigments. In November, when Dr. Linda Katz, director of the agency’s Office of Cosmetics and Colors, gave a presentation at a conference on tattoo safety in Berlin and was asked whether the country would align its regulations with Europe’s, she responded: “That remains to be seen, and we’re working on that area itself.”

De Pase, who is known for the photorealism of his tattoos — particularly his portraits — which he inks in his home studio, says he carefully mixes different shades to achieve the subtleties of skin tone. “I’m well-known because of my color tattoos,” he said. “For me, this is an issue.”

Once the rebellious mark of sailors and bikers, tattoos long ago shed any vestige of being a fringe art form. Surveys indicate about one-quarter of Europeans aged 18 to 35 and nearly one-third of American adults sport tattoos. Given all that inked flesh, documented complications are relatively uncommon and typically involve bacterial infections or allergic reactions. But regulators have not kept up with the popularity of body art. Only a few European countries exert national oversight of tattoo inks. Until this year, there were no binding standards across the European Union.

Modern tattoo inks are complex concoctions. They include insoluble pigments that provide shade or color, binding agents to keep the pigments suspended in liquid as they are transferred to the skin and water and other solvents such as glycerin and alcohol that influence the ink’s qualities, along with preservatives and other additives.

Upon injection, some pigment remains permanently in the skin, but it can also migrate to the lymph nodes. When exposed to sunlight or during laser removal, pigments may also cleave into new, potentially more toxic compounds and circulate throughout the body.

Over the years, traditional ink manufacturers have incorporated heavy metals such as barium and copper into their pigments to create a widening palette of colors, and neurotoxic agents like cadmium, lead and arsenic have been documented in some inks in high concentrations. These elements may also be found in so-called vegan inks, which merely exclude animal-derived glycerins and other ingredients.

Since 2015, Europe has required manufacturers to label inks indicating hazardous ingredients they contain. But because raw pigments are manufactured at industrial scale for use in all manner of products, including clothing and automobiles, they are not always of a purity one might hope for in a substance injected into one’s skin.

Ines Schreiver, co-director of the Federal Institute for Risk Assessment in Germany, which focused on the toxicology of tattoos, said that basic questions about the body’s exposure to the inks remained unanswered. Among the unknowns are how much ink enters the body, the relationship between that exposure and adverse reactions that occasionally follow and any illness that may emerge years later.

“I would not use the word ‘safe’ or ‘unsafe’ to describe tattooing,” she said. “I tell my friends to inform themselves about possible side effects and about the uncertainties.”

After lengthy deliberations by the European Chemicals Agency, the European Commission opted to focus on substances known to be hazardous, banning a long list of chemicals already prohibited for use in cosmetics and sharply limiting the concentrations of certain corrosive or irritating compounds.

The ban included two pigments, Blue 15:3 and Green 7, based in part on decades-old research that linked their use in hair dyes with elevated risk of bladder cancer. Acknowledging ink manufacturers’ objections that there were no substitutes for those pigments but lacking evidence to affirm their safety, the commission delayed its prohibition until next year.

“The substances are injected into the human body for permanent and prolonged contact — for life,” said Ana María Blass Rico, a commission policy officer. “So that’s why it’s so protective.”

Dr. Jorgen Serup, a Danish dermatologist who since 2008 has run a renowned “tattoo clinic” at Bispebjerg Hospital in Copenhagen, said regulations were overdue. But in his opinion, these were poorly targeted, proscribing many substances that would never be used in tattoos while failing to address known problems like bacterial contamination of inks during production. Among thousands of patients he treated for complications, he found that red was more commonly associated with allergic reactions. “There is, from the clinical side, no reason really to ban blue and green,” he said.

In the United States, where many tattoo inks used in Europe are produced, manufacturers rushed to reformulate their products to meet the new standards. One of the leading suppliers, World Famous Tattoo Ink, has a new facility in Greenville, South Carolina, where each month in a sterile clean room, 400,000 bottles are filled and packaged.

The owner, Lou Rubino, opened his first tattoo supply shop on St. Marks Place in New York in 1998, shortly after the City Council lifted a long-standing ban on tattooing so that underground artists could work openly again. At the time, the company made its inks in a warehouse on Long Island. “I used to have people that would sit there filling the bottles with a commercial iced tea container with a spout on the bottom,” he recalled.

World Famous had updated its products previously, for example to remove a formaldehyde-based preservative that had been banned in Switzerland. But Rubino said the new regulations have required far-reaching changes, forcing the company to pay laboratories extra to assess whether the products met the allowable limits for the chemicals. Because World Famous did not test its products on animals, employees and their families and friends volunteered their skin to gauge the performance of the new inks.

Although World Famous had been exploring replacements for the banned pigments, Rubino said they had not yet found any suitable substitutes. “If that doesn’t work out, there’s going to be a lot less blue and green in tattoos,” he said.