Conservation and restoration of the ceiling and four lunettes located in the Brumidi Corridors of the United States Capitol: The decoration was executed in tempera directly on the ceiling and walls between 1856 and the 1870s when the newly completed Senate Wing was decorated. The two lunettes on the west and east walls are believed to have been painted by James Leslie. The room measures approximately 23’ x 24’ and has a groin vault ceiling.Our existing conditions analysis revealed that some faulty cohesion existed in the painting’s plaster support layer, that much of the paint layer suffered minute flaking, and that approximately 90% of the ceiling decoration had been heavily overpainted in the past during three previous restoration campaigns. The overpainting added to the original surfaces had been done in tempera paints – the same medium as the underlying original. As testing proved that removal of the overpaint critically threatened preservation of the original, re-coloring the overpaint to match the original was found the only safe course after consolidation of the plaster and the paint layer. A portable digital microscope was used on site to search small areas of exposed original so that the correct palette could be used to recover the original aesthetic character of the decoration.