These superb engravings were printed in color using a so-called "à la doll" technique, in which colored inks were applied directly to the copper plate, and a single impression was made, then the colors then refined by hand.
This highly skilled and expensive technique was rarely used, but the results, as seen here, are impressive, giving a bright, clean look.
The engraver normally worked from the original painting or a watercolor copy. These were engraved by J Duthé, a French engraver active between c1800-1840,