In the beginning of the 18th century lead-tin-yellow, which beside yellow ochres was the most common yellow pigment since the Middle Ages, was completely replaced by Naples yellow. In the middle of the 18th century prescriptions for the manufacture of Naples yellow are given in the technical literature, proposing extremely great variations in the kind and quantities of raw materials. From this it can be assumed that the properties of Naples yellow should vary considerably, depending upon its method of manufacture. By means of a microanalytical examination of Naples yellow it seems possible to determine the recipe which was used for its preparation, in order to distinguish products of different origin. -- AATA