Texture can be added so that only bits of it peek through, or through all layers after the painting is finished. To do this, create a new layer, press Shift-Delete (PC:Shift-Backspace), choose 50% Gray from the Use menu, and click OK. Then take this layer into the filter gallery to apply the texture and change the layer’s blend mode to Overlay or Soft Light. The reason for putting this on a separate layer is that if you later want to have the painting printed on canvas, you can easily turn it off or delete it.