When measuring powder with a spectrophotometer, the measurement value varies depending on the density of the powder
and the surface conditions. To avoid errors, special methods are required such as placing a fixed amount of
powder into a container of a fixed shape and size and maintaining a fixed surface quality.
If the size of the particles is large, use a spectrophotometer which has a large measurement area,
so the measurement surface is averaged and repeatable measurement values can be obtained.