etchings. Some of the lithographs are of figures slightly draped; two or three of the very finest are of Thames subjects—including a "nocturne" at Limehouse; while others depict the Faubourg Saint-Germain in Paris, and Georgian churches in Soho and Bloomsbury in London. The etchings include portraits of family, mistresses, and intimate street scenes in London and Venice. Whistler gained an enormous reputation as an etcher. Martin Hardie wrote "there are some who set him beside Rembrandt, perhaps above Rembrandt, as the greatest master of all time. Personally, I prefer to regard them as the Jupiter and Venus, largest and brightest among the planets in the etcher's heaven." He took great care over the printing of his etchings and the choice of paper. At the beginning and end of his career, he placed great emphasis on cleanness of line, though in a middle period he experimented more with inking and the use of surface tone. Butterfly signature and painting settings Whistler's famous butterfly signature first developed in the 1860s out of his interest in Asian art. He studied the potter's marks on the china he had begun to collect and decided to design a monogram of his initials. Over time this evolved into the shape of an abstract butterfly. By around 1880, he added a stinger to the butterfly image to create a mark representing both his gentle, sensitive nature and his provocative, feisty spirit. He took great care in the appropriate placement of the image on both his paintings and his custom-made frames. His focus on the importance of balance and harmony extended beyond the frame to the placement of his paintings to their settings, and further to the design of an entire architectural element, as in the Peacock Room. The Peacock Room Harmony in Blue and Gold: The Peacock Room is Whistler's masterpiece of interior decorative mural art. He painted over the original paneled room designed by Thomas Jeckyll (1827–1881), in a unified palette of brilliant blue-greens with over-glazing and metallic gold leaf. Painted in 1876–1877, it is now considered a high example of the Anglo-Japanese style. Frederick Leyland left the room in Whistler's care to make minor changes, "to harmonize" the room whose primary purpose was to display Leyland's china collection. Whistler let his imagination run wild, however: "Well, you know, I just painted on. I went on—without design or sketch—putting in every touch with such freedom ...