Painting a bathroom: colour and finish
The walls. Contrary to received wisdom, a bathroom is painted in matt: Marble Matt Emulsion is washable and breathable, and it lets the wall release moisture rather than trap it. It suits every wall that doesn't take direct splashes. Around the basin, the bath and in a walk-in shower, switch to Multi-Surface Eggshell, moisture-resistant, which wipes clean in one pass. The vanity unit, the door and the radiator are painted in Multi-Surface Satin.
Choosing by light and size
A windowless bathroom has no reason to be white: under constant artificial light, a mid colour such as Bridge Blue No.222 or Eaton Square No.232 is more flattering than a white that will look grey. A north-facing bathroom likes green-undertoned blues — Notting Hill No.213, Glass BH.09 — and avoids pure blues. A small bathroom grows with a light colour on walls and ceiling (Copper Green No.36, Morning Blue No.32) — or, conversely, becomes a jewel case with a deep colour everywhere.
See also Which finish for a bathroom?, our greens for a bathroom and our bathroom ideas.