Christopher A Rose AIA, ASID This is Farrow and Ball no 231 Setting Plaster. Please note due to orientation, amount of windows, and many factors which can affect the perception of color so get a small amount and try in your space and look at it different times of day. I think you can have SW mix to match but it may come out differently.
This ceiling incorporates two steps of soffits. The first and lowest soffit follows the geometry of the room, as does the area rug directly below it. The higher soffit is a rectangular shape to provide a centering device. This type of ceiling gives an order and structure to a room that incorporates different angles and asymmetry. The lower soffit also provides a wider flat area at the bed headboard. This wide and flat area gives more intimacy at the headboard area as well as a place for ceiling-mounted items such as grilles, speakers, etc.