Rock art fans flocked to San Francisco’s Golden Gate Park on Saturday for the chance to see and buy music posters from over the decades and meet the artists behind them.

The Festival of Rock Posters, which has been running for 20 years and showcases more than 50 artists, this year featured U.K. artist Roger Dean, whose album cover illustrations are intricately associated with progressive rock bands including Yes and Asia, andBrian Chambers, whose studio in Grass Valley (Nevada County) showcases psychedelic art.

院长的原始painting for Yes’ prog-rock staple“Relayer”was on display at the festival, as were silkscreens byZoltron, the secretive artist who introduced psychedelic imagery to a new generation of fans with designs for Primus, the Black Keys and Soundgarden.

Also in attendance was the family of Bay Area artistRick Griffin, the illustrator of many Grateful Dead posters, who died after a 1991 motorcycle crash in Petaluma. Exclusive prints of Griffin’s album cover art for the Dead’s“AOXOMOXOA”were available to the public for the first time.

Also on sale was a special Artist Relief Trust benefit poster, illustrated by Dave Kloc, who has illustrated for bands including Metallica, Phish and the Foo Fighters. The proceeds of sales of that poster go to support rock poster artists struggling with medical bills or and other financial burdens.

Admission to the festival, organized by theRock Poster Society, cost $40 when the doors of the Hall of Flowers opened at 10 a.m., gradually going down in price throughout the day until the event was free by midafternoon.

Reach Danielle Echeverria:danielle.echeverria@sfchronicle.com; Twitter: @DanielleEchev