In this work, the strategy, performances and applications of a Raman spectroscopy system with both optical fibre technology and two lasers (red and green) are presented. With this system, we have investigated certain yellow pigment from Italian paintings of the XVII century whose composition is not yet exactly known. The comparison of its Raman spectrum with the spectra of two yellow patterns that we have produced demonstrates the triple oxide composition (Pb, Sn and Sb) of this Italian pigment. This result is in good agreement with the previous works obtained by other authors with scanning electron microscopy-energy dispersive X-rays (SEM-EDX). The paintings we have analysed here are “Lot and his daughters”, by G.B. Langetti, and “Entrance of Christ in Jerusalem”, by Luca Giordano.