until the desired long-lasting colour, hand, gloss and appearance is obtained. Polishing, plating, pressing, fulling (or fulling) and buffing are mechanical operations; chemical finishing, generally by spraying, covers the leather with colouring, matting or polishing mixtures, depending on the result required. This is the most delicate phase of leather processing, from an aesthetic and functional point of view, the one in which the innovation and creativity of the tanning art reaches its peak, in constant connection with the most advanced scientific research.