Malvern Instruments Ltd. has published a paper on the research and methodology for measuring the size, shape and intensity of particles in mineral-based powder makeup using its Morphologi G3 image analysis based particle characterization system.
"Morphologi G3: Understanding Mineral-based Make-up Using Size, Shape and Intensity Measurements" discusses how to capture and analyze data for use in optimizing the brilliance and coverage of powder makeup.
In writing the paper, the company conducted a comparison of three commercially-available mineral makeup powders. After measuring the particle size of the three powders, the company concluded that particle size affects the final makeup appearance. Large particle sizes resulted in a powdery look whereas small particles resulted in an insufficient masking effect.
The company also noted that the shape of constituent particles affect their light dispersing properties may influence final product performance. A pearlescent effect is possible with plate-like crystals, and the size of the plates determines the level of sparkle. Small plates give a more opaque smooth finish, while larger plates add a brilliant spark.