(Credit: Scott Cadenhead) Gemma Summerfield has joined the roster of Promethean Artists for General Management. Summerfield will be represented by Artist Manager Callan Coughlan for operatic, orchestral, and recital engagements throughout the world. In a statement, Summerfield said, “I am delighted to be collaborating with Promethean Artists as we look to the future together. I am impressed by the team’s {…}