Pretty in White: Making an All-White Room Work
An all-white room sounds like the easiest scheme in the house and is usually the hardest. White is not a single colour; it is a whole family of them, each carrying a faint cast of yellow, grey, pink or green. Put four of those casts in one room without thinking about it and the result reads as slightly dirty rather than crisp.
The useful way to start is to decide which direction the room's light comes from. North-facing rooms take a cool, blue-grey light for most of the day, and a white with a yellow cast will turn faintly cream in it, which may be exactly what is wanted. South-facing rooms get a warmer light that can make a cream white look buttery and a grey white look calm. Neither answer is better; the mistake is choosing without looking.
Once the direction is set, build the scheme from three whites rather than one. A chalkier, flatter white on the ceiling, a slightly warmer white on the walls and a cleaner, brighter white on woodwork gives the eye something to measure. The differences are small enough that a visitor would not name them and large enough that the room has depth.