Industries that must meet specific grain sizing procedures such as ASTM E112 often use microscope eyepiece grain counting reticles. Test Method E 112 is one of the most widely cited ASTM standards. This method deals with the measurement of grain size when the grains are not deformed in shape, although it does contain some information about measurement of grain size when the grains have been elongated by processing.
Learn more about the uses of grain counting reticles and the options available for purchase here.
Complete ASTM E112 Standard test methods can be found here.