What's happened to it? I have recently bought a tinlet (No.34) and despite giving it a thorough stir it doesn't cover anything like as well as it used to. in fact it barely covers at all, looking more like wood varnish does before it dries. I normally use Tamiya acrylics but I've always had problems with their flat white so have used Humbrol for white instead. Humbrol has always covered well until now. Brush painting, of course.
Has anyone else had this problem?