The annual four-day Full Frame Documentary Film Festival that was held in Durham in April brought in $320,000 more for the local economy than it did last year, for a total estimated economic impact of $2.1 million. That’s according to the Durham CVB, which generates local economic impact estimates using studies from two market research firms along with data from festival organizers, said Shelly Green, the bureau’s president and CEO. The festival, a program of the Center for Documentary Studies at Duke University, also generated around $73,000 in tax revenue for the city. That total was up by about $20,000 compared with last year. The festival drew more than 32,000 patrons with 38 sold-out events. Green said another benefit of the festival is its “billboard effect” for Durham – helping spread the city’s name as the annual host of the event. “Once that’s held here year after year after year, where the name of the city becomes a part of what the festival is, [it] has another kind of value that’s hard for us to put a dollar sign on,” Green said.