Reynolds was the chief proponent of the Grand Manner, and, as the NGA points out, the two years involved in completing the portrait would have aged the children noticeably.

"But Reynolds worked from abstract principles of design rather than observation of nature," the NGA writes, "One of his conceptions for Grand Manner likenesses was: Each person should have the expression which men of his rank generally exhibit.

Cynthia Saltzman writes in Old Masters, New Worlds (2009) that "Lady Delmé has a long, elegant face, heavy-lidded eyes, and towering powdered hair.

She wears a white dress and a cloak that covers her knees in a cascade of rose-colored satin that speaks both to her beauty and to the luxury at her command."

Saltzman notes that Lady Delmé is one of the finest representatives of Reynolds's intent to raise portraiture to the level of history painting.