After working on a piece for a few hours I had a layer set over a sketch I did for darker lines, wanted it to be separate from said sketch. After exiting and coming back to it I realised that the layer had been dropped and lines had merged with the sketch and I don't want that to happen, is there a way to separate the lines from the sketch? I'm also using Corel Painter Essentials 6, any help or advice would be much appreciated.
I don't think so. To preserve your layers when saving Save as a .riff file. Otherwise the layers will collapse if saving as jpeg, png, etc.