Long before Charlotte Free, the of-the-moment fashion model, became known for her brightly colored hair, which ranges from pale to neon pink, women were dousing their manes in Crayola hues. The coloring process has not changed much since the days of 1980s punk rockers and ’90s grunge enthusiasts, but the patterns, placement and mood of these “shock locks” have evolved.

Some women are even wearing them to the office, as does Numidas Prasarn, 26, who works at the visitor center at the Brooklyn Public Library. She keeps her purple hair long and simply styled.

“It is a conscious effort to address how I feel every day,” Prasarn said of the coordination her coif requires. “Do I feel like going with this color or fighting against it?”

Prasarn’s hair is monochromatic, but Sally Hershberger, a celebrity hairstylist with salons in New York and Los Angeles, cited “cascading tips” as one way of incorporating brightness that “feels fresh now.”

Hershberger added that the entertainers Nicki Minaj, Hayley Williams and Katy Perry — all of whom have gone bright in one fashion or another — have all influenced her customers.

“Because of them, a lot of the hip chicks want their hair done like that,” she said. Coloring extensions has become popular, she said. “And they’re also doing pink fading into purple.”

The trend gained traction after the spring 2010 runway shows and reappeared in the 2011 shows. Julia Wideman, an assistant manager at the Bumble and bumble salon, whose chestnut hair is lavender and green at the ends, said she was influenced partly by styles shown at the Proenza Schouler show.

“I also pulled a whole bunch of inspiration, from My Little Pony to old women who frost their hair,” said Wideman, who first dyed her hair pink, then purple after seeing a picture of hot-pink locks on a friend’s blog.

It might not be surprising that Wideman, or Dani Stahl, the style director at Nylon magazine (a trendsetter first with her brown and blond ombre bob, who later added pink to the mix), have taken to shock locks. But Olivia Goyrn, a Web content manager at an advertising company in Manhattan, is a less likely candidate.

Before Goyrn, 26, dyed her shoulder-length hair neon pink, she warned her employers, she said, and was happily surprised to find that they were fine with her new ‘do.

“Generally, I try to walk the line between grown-up goth and professional,” she said. “So far it’s working.”

Conscious of the adolescent mood that brightly colored hair projects, many women above drinking age take pains to match it with conservative attire.

“You expect to see somebody who listens to Nirvana and never showers and lives that kind of grungy lifestyle,” Wideman said of the impression her hair risks leaving. “I like to do the exact opposite with my clothing. In order to balance it out, I wear cleaner lines and crisper colors, more monochromatic and more neutral.”

But swagger alone is not enough to pull off bright hair. Whether done in a home bathtub or in a salon, the right technique, which can involve stripping all of the hair’s natural color with bleach for maximum saturation, is crucial. Women fearful of causing damage or just nervous have many noncommittal options, like clay and henna, which are available at health-food stores; Manic Panic’s new colored styling gel; and clip-on tracks in Rainbow Brite colors, like those made by Paul’s Hair and Beauty World or Sally Beauty.

Rebecca Faye, a former stylist with Patricia Field who now owns two salons, prides herself on being able to paint any pattern, including leopard print, into hair. She prefers to use products from Special Effects because they last longer and fade better, she said.