How should we evaluate an assistant’s role in the act of creation? Does it really matter if artists touch their own works, as long as these works are unique and are made in their presence? “Regardless of the artist’s distance from the process,” Paulson says, “there is a nuance that gives it his identity. If there were to be dot paintings generated by someone who used to work for Hirst, you would feel it, and it would not be seen as having any value in the market.”

By helping an established mentor, novices learn firsthand what being a working artist actually involves. The painter Carroll Dunham assisted Dorothea Rockburne off and on from 1970 through 1973 in New York. “In a way, that was my art school,” he says. “It’s important to be involved with the daily operation of a studio and how you organize it both physically and psychologically. But the best part was the incidental talking about art.”

Today many aspiring artists skip this journeyman step. They enter the market while still in school, as collectors buy work from thesis exhibitions and dealers cherry-pick talent for group shows. Not long after graduation, the most promising may be preparing solo debuts and hiring assistants of their own out of the same pool.

At 28, Dan Colen is a budding star who was featured in the 2006 Whitney Biennial and whose paintings sell for around $50,000 each, according to his dealer, Javier Peres, of Peres Projects, in Los Angeles. Lately, these works have been colorful abstractions that Colen calls “bird shit” paintings—an accurate description of their appearance. “He made the first couple of them and gave us directions,” says Theo Rosenblum, one of five $15-an-hour part-time workers in Colen’s New York studio. “A lot of the work involves developing our own ways of painting them. That is what’s interesting: There are different styles of bird shit. The way these paintings are, it’s almost better to have different hands on them.”

No such leeway is given to the staff at Koons’s studio, which was operating around the clock last spring to prepare paintings for a show at the Gagosian Gallery in London in June. “There’s a learning curve,” says Koons’s longtime studio manager, Gary McCraw. “The painters learn how Jeff sees things so they can make his art. The work is very labor intensive. Tracing might require six people on one painting. Basically, he’s quality control.”

Murakami runs an even tighter ship at his studios in Asaka, Japan, and Long Island City, New York, which are modeled on both Warhol’s Factory and the artisanal workshops of the Edo period in Japan. The artist has 35 employees in New York alone and nearly 20 in Tokyo. “All of the design work is done on computer in Japan,” says Yuko Sakata, director of the New York offices of Kaikai Kiki, the company that produces Murakami’s paintings, sculptures, prints and animations and also manages the careers of seven other Japanese artists. These include Chiho Aoshima and Mr., who both worked for Murakami.

Although many artists maintain large studios like Murakami’s and Koons’s—Matthew Barney and Julian Schnabel are two who combine art making with film production— others prefer a more personal approach. “I’m a mom-and-pop operation,” says Ross Bleckner, who brings in one or two art students to work in an office beside his studio but prefers to create alone. “I’m the mom—and I’m the pop. And I like to keep it that way.”

Kiki Smith retains two assistants to help her in her studio and one to run her office. “What I like is that, when people show up at a certain time of day, it kicks you out of your own subjectivity and forces you to think in an orderly fashion instead of drifting,” she says. “For self-employed people, that’s a big thing.”

What about the impact of such jobs on the assistants? They can reap unexpected benefits—but there are also drawbacks. Painter Carl Fudge, who spent nearly 10 years in Smith’s employ, says he started out “grinding glass sperm” but soon found himself becoming part of her life: “She used me as a barrier against people she didn’t know. I sort of protected her.” He also helped install her shows all over the world. “We went to amazing places and met the most interesting people,” he recalls, referring to such travel, however, as “a great experience rather than a career benefit.” His tenure, which ended in 1998, affected his own identity as an artist as well. “Even a couple of weeks ago,” he says, “a museum called asking for Kiki.”