Royal portraits tend to veer between the staid and the controversial. Lucian Freud's 2001 portrait of Queen Elizabeth II remains a particularly notorious example, with some describing the heavy, severe painting of the monarch as deeply unflattering and others calling it groundbreaking.
In fairness to Emsley, some artists had praise for his work.
"I liked it, very much so," said Richard Stone, who has frequently painted members of the royal family. "So often with official portraits they can be rather stiff and starchy, but this has a lovely informality about it, and a warmth to it."
In any case, Emsley appeared to have won over his most important audience. Kate, who was with her husband, Prince William, at the gallery earlier Friday, called the portrait "just amazing." William liked it too, saying it was "absolutely beautiful."