At Nations Photo Lab in Hunt Valley, Tadder stands over a conference-room table with Joyce Frampton, the lab's bubbly customer relations manager. They examine each fine-art print before it is packaged and sent to the Unicorn Gallery in Fells Point for display and purchase. One print stands out, different from the rest. It is a montage of two images of Paul McCartney, one shot by Tadder that September day in 1964, the other shot by Tadder's son, Tim, a noted photographer in his own right, during the halftime show of Super Bowl XXXVIII. Tadder holds up the print and smiles. "One icon, two photographers, 40 years apart." And the rest is history.