The chart above shows just how substantial this week’s breakout sale was for Swann and the African American art category. Swann has been steadily building the category with solid yearly sale numbers and the addition last year of a third sale in the annual cycle. That new sale might be one of the contributing factors. Or the Philadelphia Museum’s survey of African American art, Represent, that closes this weekend might also contribute to the growing interest in the category. Whatever the source, yesterday’s sale was a significant step up in volume and average price suggesting a whole new trajectory for the category.