Abstract: The invention relates to a method and apparatus for automatic analysis for determining the size distribution of particles and their deviation from a desired shape and color. The method includes the collection of particle samples and the generation of a particle curtain in a monolayer form. It is formed by taking particles through a silo whose distance (a) to a vibrating plate positioned below has a length relative to the distance (b) between the outer edge of the plate and the center line of the silo that is large enough for the particles flowing out of the silo and down onto the plate and out over its edge to form an angle .alpha. with the horizontal plane. The angle .alpha. is 50-90% of the sliding angle of the particulate material. The particle curtain is lit up and the silhouette of the particles therein is recorded and analyzed and presented in at least one place.