This paper focuses on analytical investigations into the use of coloured glasses and associated materials in sixteenth-century paintings. Among a variety of new materials, coloured glassy pigments including diverse yellow glassy particles were analysed and found to be lead silicate and glass coloured by lead antimonate. These are the yellow smalts described in Renaissance writings on artists' materials. Samples were examined using scanning electron microscopy with simultaneous energy dispersive spectrometry (SEM-EDS) to obtain chemical evidence to complement and augment the written materials evidencing the use of a wider range of materials for pigments, including glasses. There is growing evidence that artists also used other materials to prepare their paints. Pulverized quartz, for example, a raw material used in the glassmaking industry, was found in transparent paint. The optical and tonal effects of these types of materials contribute to the appearance of the final painting. -- ICCROM