I'm painting a ceiling using half a tin (previously used) of Dulux Once. When I opened the can there was some slightly browny water on the surface which I mixed in thoroughly. The can is plastic not metal, so it wasn't from rust. Now I'm painting the ceiling it seems the old colour is brighter than the new paint! Has that watery stuff discoloured the paint slightly do you think? I'm now having to wait whilst it dries to see if it dries any better before I continue. I haven't known matt paint to separate out before. Anyone else got some experience here?
I've got another 'keen'... Ouch!