Given the following context:  William Etty (1787–1849), the seventh child of a York baker and miller, began his career as an apprentice printer in Hull at the age of 11. On completing his seven-year apprenticeship he moved to London "with a few pieces of chalk crayons", with the intention of becoming a history painter in the tradition of the Old Masters, and studied under renowned artist Thomas Lawrence. Strongly influenced by the works of Titian and Rubens, Etty submitted numerous paintings to the Royal Academy of Arts and the British Institution, all of which were either rejected or received little attention when exhibited.In 1821 the Royal Academy accepted and exhibited one of Etty's works, The Arrival of Cleopatra in Cilicia (also known as The Triumph of Cleopatra), which depicted a large number of nude figures. Cleopatra was extremely well received, and many of Etty's fellow artists greatly admired him. He was elected a full Royal Academician in 1828, ahead of John Constable. He became well respected for his ability to capture flesh tones accurately in painting, and for his fascination with contrasts in skin tones. Following the exhibition of Cleopatra, over the next decade Etty tried to replicate its success by painting nudes in biblical, literary and mythological settings. Between 1820 and 1829 Etty exhibited 15 paintings, of which 14 included nude figures.While some nudes by foreign artists were held in private English collections, the country had no tradition of nude painting and the display and distribution of such material to the public had been suppressed since the 1787 Proclamation for the Discouragement of Vice. Etty was the first British artist to specialise in painting nudes, and many critics condemned his repeated depictions of female nudity as indecent, although his portraits of male nudes were generally well received. From 1832 onwards, needled by repeated attacks from the press, Etty remained a prominent painter of nudes, but made conscious efforts to try to reflect moral lessons in his work.  answer the following question:  What is the last name of the person who was known for their fascination with contrasts in skin tones?
Answer:
Etty