September 3, 2015 12:01 AM EDT

Developing a long-term documentary project requires a combination of dedication, time, and funding. Without all three, completing a polished product is nearly impossible. But finding ways to fund these projects over the years has become difficult, especially in a market where editorial assignments are in decline.

TIME LightBox selected five of the most successful documentary projects and spoke with the photographers asking them how they funded their work.

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