To keep pace with modern-day mass production of consumer and luxury goods, the coatings industry has hastened to update technologies and deliver different kinds of coatings for various applications that hold up to corrosion, weathering effects and tightening environmental legislations. One route to better products is the close control of particle size and size distribution since both of these parameters influence a number of important coating characteristics. Powders have an “average particle size” as described by the manufacturer of the pigment, filler, etc. In reality, powders are often supplied in an agglomerated form so that while the average size of primary particles is 8-10 microns, the average agglomerate size might be 200-600 microns. When the powder is added to a fluid, further agglomeration can occur. Mixing and milling operations, therefore, reduce the size of agglomerates rather than primary particles. In this article, the term "particle size" is used within the above context.