Physical Parameter of Pigment Carbon black 1.Particle diameter means the diameter of a single(random) particle generated in the burning of a sort of oil.Average particle diameter means extracting some particles of limited weight or unit weight and calculating the average particle diameter. 2.specific surface area means the area that a unit weight powder occupys.This figure is related to particle diameter. 3.DBP absorption value, means the oil absorption volume of unit weight. In general,the less absorption value,the better glossiness in pigment product. 4.PH,the best is neutral,that is PH≈7.That would be good to the plastic performance. 5.Blackness,some factories measure the blackness with iodine absorption number.The higher iodine absorption number,the higher blackness. 7.Tinting strength,means the percentage of the carbon black coloration in production process.