My wife is painting white the ceiling of our kitchen in order to help lighten a dark room. The ceiling is all exposed wood of a medium brown colour. I'm not sure what, if any, finish has been on the wood, though definitely no previous paint. She is using Dulux Brilliant White Emulsion for Walls and Ceilings. The paint goes on pure white but then dries to a very pronounced cream. We thought this might be the effect of the wood showing through the first coat, but now the second coat looks exactly the same cream colour when dry. Any explanation of this unexpected phenomenon or suggestions of what she should do (or should have done) would be greatly appreciated.
If your house was previously occupied by a smoker then the stain is nicotine otherwise it is a water soluble dye coming out of the wood. You will need to seal the area with a stain blocker (2 or 3 coats).