(EN) The present invention is directed towards a method of determining the state of a substance (2) having a color property dependent on the state of the substance. The method includes the following steps: forming a pixel image of the substance (3) using a camera (3); projecting the pixel image into a three- dimensional color space using a neural network (7); and comparing the projection (37) with a projection of a second position of the substance (2) to determine the state of the substance (2) using a second neural network (9).