This practice is of value (1) to the producer of fine particles as a means of reporting particle characteristics with respect to quality control and (2) to the buyer to assure that the particle size and particle size distribution meet his requirements.

1.1 This practice for reporting the fineness characteristics of pigments is designed to apply in most cases where well-known methods for determining these particle size characteristics in the subsieve range are employed, such as microscopic, sedimentation, and turbidimetric methods; and partially to absorption and permeability methods.

1.2 Laminar, plate-like pigments and composite pigments having a definite bimodal distribution are not considered within the scope of this practice.

1.3 Parameters—The fineness characteristics are reported in the following three parameters:

1.3.1 Particle Size Parameter .

1.3.2 Coarseness Parameter—A parameter descriptive of the coarseness character of the pigment, making use of a limiting value in the subsieve range similar to that used in the sieve ranges.

1.3.3 Dispersion Parameter -A parameter descriptive of the uniformity of the particle size distribution.

1.4 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.