When she finished, she ran the calculation: Volume fraction of voids = 11.8%.

Using a 500-point grid on a single field of view creates data redundancy. Points that are too close together sample the exact same phase particle, wasting time without improving statistical relative accuracy. Spacing between grid points should ideally be larger than the average size of the phase pools being measured.

= (the number of points falling within the phase divided by total grid points). By establishing that the point fraction ( PPcap P sub cap P ) directly matches the true volume fraction ( VVcap V sub cap V

ASTM E562-19e1 provides the "ground truth" for these measurements, ensuring that different labs and manufacturers can produce comparable, accurate data. 2. The Methodology: Systematic Manual Point Counting