Some call them propaganda.

To others, they are necessary artistic weapons in the fight for freedom.

They have been used to support everything from libraries to labor movements. Above all, political posters illustrate the role art, symbology and slogans play in popular culture.

Last October, the Oakland Museum of California acquired the Michael Rossman collection of political poster art - a vast catalogue of 23,500 works documenting social movements from the ‘60s to the ‘90s, archived by artist and historian Lincoln Cushing.

This Friday - as part of its monthly Ozone event - OMCA will host a Political Poster Jam, which brings Cushing together with Oakland artists Favianna Rodriguez, of the Taller Tupac Amaru collective, and Emory Douglas, best known as the former graphic designer and Minister of Culture for the Black Panther Party. Carol A. Wells, director of the Center for the Study of Political Graphics, will moderate what promises to be a lively, and enlightening, discussion.

But the jam is more than just a lecture/discussion - it also features an interactive component. The San Francisco Print Collective, Great Tortilla Conspiracy and artist Eddie Colla will host drop-in workshops highlighting stencil, linocut, screenprint and digital techniques - with T-shirts and tortillas available so you can make your own artwork on wearable or edible media. Artist Jesus Barraza has created a special poster for the event, and music will be provided by Amoeba (plus there’s a special DJ set by Rodriguez).

As Museum curator Rene de Guzman explains, “With the Political Poster Jam, we'll celebrate OMCA's "All Of Us Or None" political poster collection and empower people's creativity to make their own views known in public spaces. Given the recent revolution in Egypt, it seems timely to consider how citizens in any society affect ways to express political desire and need, whether through traditional print media or through social media and high technology.”

It’s interesting that de Guzman mentions Egypt, whose recently-deposed leader Hosni Mubarak used political signage as a way to emphasize his totalitarian rule. Returning to Cairo via bus from Sharm-El-Sheik back in 2001, this journalist recalls traveling through hundreds of miles of desert with nothing around – except for larger than life billboards depicting Mubarak’s Big Brother-esque visage. Creepy.

And in 2010, on a visit to Havana, Cuba, one couldn’t help but notice the political billboards advertising the anniversary of Castro’s socialist revolution – they were everywhere.

Closer to home, poster art has for many years been associated with the social and cultural revolutions of the Bay Area – a veritable breeding ground for such work.

“The San Francisco Bay Area is one of the most prolific places in the world for the production of independent political posters, with an unbroken tradition spanning over 45 years," Cushing said. "'The All of Us Or None Collection' now at OMCA reflects the incredibly rich, talented and cooperative community of graphic artists, print shops and activist organizations that show how this democratic public art contributes to the movements for social justice.”

Rossman, Rodriguez noted, was a strong influence on her own poster work, and she considers the collection "a vital learning tool" in her artistic development.

"The Bay Area is one of the most vibrant epicenters for political art in the country, and I'm honored to be celebrating the AOUON collection that documents this rich history," Rodriguez said. "Art is a powerful tool for civic engagement and this event will highlight how graphics in particular helped advance a community-centered agenda. I highly encourage parents, teachers, youth and art lovers to attend and learn about the how art can build a better and more just world."

Along with the Political Poster Jam, this special Black History Month-themed edition of Ozone - which runs from 5 p.m. to midnight - boasts a full, intriguing and amazing lineup of cultural events and activities, from jazz to Afrobeat to body music. The overarching theme is “The Drum,” that ubiquitous instrument inseparable from African music, which replicates the human heartbeat.

There’s too much going on at Ozone to list it all, but a run down of all the happenings is here.