I have painted the ceiling and cornices of my hallway with flat white ceiling paint and the cornices keep coming up shiny and patchy. I put plenty of paint on the brush. The hallway has both old and new cornice and both are affected in the same way. Can anyone tell me how to fix it?
One possibility is there is something bleeding through the paint. If this is the case you will to need to prime with a good sealing oil base or shellac primer.
Another possibility is they simply need another coat.
Re-coat and see what happens. If the discolored/patchy areas return try priming.