There is evidence that Jefferson's private chambers - the Book Room, Annex, Cabinet, and Bedchamber - were originally wallpapered, but unfortunately there is not sufficient evidence for reproductions. The walls in these rooms have been painted a neutral color, called "Oyster White." This color was custom-mixed for Monticello.
The blue in the Dining Room is not an original color, nor does it date to Jefferson's ownership of Monticello. The room was originally just plaster, then had an application of a "chrome yellow" oil paint sometime after 1815, and was then papered in some yet unidentified pattern. We believe the blue was applied sometime in the late 19th or early 20th century. In 2010, a recreated "chrome yellow" paint (based on paint analysis studies) was applied to the walls of this room.
North Octagonal Room
The trellis-patterned wallpaper in the North Octagonal Room was manufactured by F. Schumacher & Co.  in the early 1990s as part of their Colonial Williamsburg Collection.
North Square Room
The North Square Room, which is not presently part of public tours of Monticello, was originally a chrome yellow, and was later wallpapered. Until recently it was unpainted plaster. In early 2008, it was repainted its original chrome yellow color.