Roman period mummy portraits are considered to be ancient antecedents of modern portraiture. However, the techniques and materials used in their manufacture are not thoroughly understood. The Phoebe Hearst Museum's collections from the site of Tebtunis, Egypt include one of the largest assemblages of mummy portraits to remain intact since their excavation, and form a remarkable resource for exploring how these lifelike portraits were painted. This talk will describe the collaborative technical study of these paintings and what it revealed about workshop practices in this cultural crossroads. Jane Williams is currently the Head of Objects Conservation at the Fine Arts Museums of San Francisco. She holds degrees in art history and conservation from Yale College and New York University.