Hammer finishes are paint or powder coatings with a metallic pigment and an additive which causes a strong orange-peel effect. Leatherette finishes are non metallic. There is a very common misconception that they are in some way tougher or harder than other paints. In fact they are basically a 'coating with holes'. They do have a place where it is necessary to hide imperfections in the object to be coated, for instance porosity or spot welds.