A chalky dusting or powdering at the paint surface, often associated with old, weathered paint film.
Precipitation of elements within the paint.
This may be due to:
a) Incompatible or defective materials within the paint.
b) Degradation of the binding agent.
c) Degradation of pigment.
a) Use recommended materials.
b) Avoid exposure to ultra-violet light (strong sunlight) and harsh shampoos.
Flat, compound and polish the surface to restore the gloss. In severe cases repaint the topcoat.