Knowledgeable people have been talking a lot about documentaries lately, about how new, smaller digital technology is allowing people to get closer to their subjects -- not to mention producing films much more cheaply. It's a renaissance for documentaries, they say. Eight documentaries released in 2006 cracked the list of the top 100 highest-grossing documentaries of all time, and another 15 currently reside on the second hundred.

But here's a simple question: how many of these would anyone want to watch a second time? How many have a shelf life? For example, here's my personal documentary "shelf life" top five: Crumb (1995, Terry Zwigoff), Fast, Cheap & Out of Control (1997, Errol Morris), Lessons of Darkness (1992, Werner Herzog), To Be and to Have (2002, Nicolas Philibert) and My Voyage to Italy (1999, Martin Scorsese).

categories Columns, Cinematical