In contrast to tagging, which is more or less the equivalent of a dog marking its territory by lifting its leg and peeing, graffiti has a long and noble history in Western society (dating back to the time of ancient Greece and Rome) and can be a highly effective way subverting dominant political/economic ideology and giving voice to marginalized viewpoints.

The key, of course, is for the artist to pick their target wisely and create thought-provoking imagery and/or text that will inspire those who view it to think more deeply about the issue that’s in play. If the artist does that then, in my mind, the graffiti they produce shouldn’t be condemned outright but rather should be regarded as an outlet for promoting freedom of expression.

At the outset of this British documentary, French videographer Thierry Guetta is intent on profiling the work of well-known graf artists like American Shepard Fairey (DogBlog) and the anonymous Brit known as Banksy. But as the film progresses, Guetta comes under Banksy’s wing, and morphs into a street artist himself named Mr. Brainwash.

Exit Through the Gift Shop plays at the RPL Theatre tonight at 9 p.m. Here’s the trailer.