One of the hardest things in the world is to determine how much realism
is allowable in any particular picture. It is of so many different kinds
too. For instance, I want a shield or a crown or a pair of wings or what
not, to look real. Well, I make what I want, or a model of it, and then
make studies from that. So that what eventually gets on to the canvas is
a reflection of a reflection of something purely imaginary. The three
Magi never had crowns like that, supposing them to have had crowns at
all, but the effect is realistic because the crown from which the
studies were made is real--and so on.
_Burne-Jones._