Messung der Homogenität von gemischten Farben

Apparatus for sensing colour blend homogeneity of at least first and second material blend portions has a light transmission plate (12) for holding the portions (24), a light source (14) for emitting a light beam, and a colour sensor. One end of an illumination assembly is optically coupled to the light source and its other end is optically coupled to and disposed normal to the to the light transmission plate so as to illuminate the material blend portions. One end of at least one detection assembly is disposed next to the light transmission plate so as to detect the diffuse reflection from the illumination from the material blend portions and its other end is coupled to the colour sensor (16). The colour sensor senses the diffuse reflecting light from the material blend portions and transforms it into tri-colour signals so as to determine their local and global homogeneity. Also claimed is on-line apparatus for sensing colour blend homogeneity in a material blend mixing vessel.