“Flagging the head” refers to placing a white shape behind the head of the most important character in a figural composition. It’s a sure-fire way to place the viewer’s attention exactly where you want it, especially when you’re working against an impossibly busy background.
In this illustration by Maurice Bower*, the woman’s head gains importance because of its position against the light of the bright window of the crowded pharmacist’s store.
In “Norman Rockwell Visits a Country Doctor,” 1947, the doctor’s face would be lost in the clutter of his desk were it not for the brightly illuminated bunch of papers behind him.
When I painted this holographic workstation, I was worried the hero would be lost in all the detail, so I flagged his head with a slanting white table. You can see the Dean Cornwell and John Berkey influences on this paperback cover from the mid 1980s.
*The Maurice Bower painting is lot 29 of the upcoming June 7 auction at Illustration House in New York, link.