Yellow hues can be obtained in glass using various chromophores. From Roman to contemporary glasses, glass colorants have evolved, from amber color due to an iron and sulfur complex to the bright yellow of CdSSe quantum dots through silver yellow given by surface plasmon resonance of metallic silver nanoparticles. The evolution of color has been made possible by the discovery of new raw materials and new processes, but some very old techniques have survived and are still used today. To establish a chronology and determine the chromophores used at different times, various stained glass windows from the 12th to the 20th century have been studied. 
Different spectroscopic methods were used in addition to the study of the chemical composition. Indeed, the chemical composition of the glass does not always allow to identify the element responsible for the color, as in the case of amber chromophore for example. Iron and sulfur are often present in an ancient glass as impurities but do not always give a yellow or amber coloration. Very precise redox conditions are necessary to give rise to the iron-sulfur complex responsible for the color.  In this case, the optical spectroscopy using portable settings on stained glass windows is very useful to identify the characteristic absorption bands of the complex. These optical absorption spectra were compared to reference spectra of modern amber glasses to better understand the chemical mechanism responsible for the color.