Describing particle size
There are many ways to measure the so-called particle size of a powder. Every measuring principle tells its own ‘truth’ so it is important to know by which technique the particle size data were generated.
Sieves, laser diffractions systems, particle counters, sedimentation techniques and image analysers all ‘see’ the particles differently - they must do so - unless all of your particles are perfect spheres!
Most of the techniques combine size and particle shape into one distribution. It is important to remember that we are dealing with distributions and that no single piece of information can accurately describe the whole sample. Beware of a specification quoting a d50 of 100 microns: this is not the whole story.
