Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for the identification of organic colorants within art samples. The SERS substrate that is widely used, a colloidal suspension of silver nanoparticles (AgNPs), does not always provide reproducible spectral results even when the same procedure is followed within the same laboratory conditions. An investigation to find a metric that can classify each new batch of AgNPs as optimal or suboptimal for application onto a precious art sample are discussed. Next, a quality assurance protocol for SERS-based identification of organic pigments in art is presented. Lastly, pretreatment extraction techniques for sample intervention prior to the application of AgNPs are illustrated
