What is hegman gage?

Hegman gauge is a vertical gap measurement tool primarily used in the paint and coatings industry to measure the particle size distribution of pigment or powder coatings. It measures the gap between two mirrored plates, with the smaller spaces indicating smaller particles. The gage is commonly used to determine the grind size of pigments in a paint or ink. The hegman gage has different scale sizes ranging from 0 to 8, with each number indicating a specific gap size in microns. A higher number indicates a smaller particle size. The instrument is named after its inventor, George L. Hegman, who patented it in 1938. It is widely used across various industries that deal with particle size analysis, including the automotive and pharmaceutical industries.