(Also known as Finger Marks and Hand Print Blistering.)
No matter how clean the hands may seem, there is always some dirt, grease, oil or perspiration which will cause blistering and poor adhesion.
Keep bare hands off the surface to be painted.
In motor body assembly plants, cars are never directly touched with human hands. After being chemically cleaned – the operators wear cotton gloves. It is a good practice for all painters to follow.