This poster discusses the characterisation of varnishes on the Philadelphia Museum of Art’s <i>Portrait of Anna Traquair Lang</i> (1911, PMA #1928–63–4) by the American painter William Merritt Chase (1849–1916). A complement of analytical techniques – Fourier Transform Infrared Spectroscopy (FTIR), Gas Chromatography Mass Spectrometry (GCMS), and Energy Dispersive Spectroscopy (EDS) – was used in conjunction with ultraviolet examination to study the varnish materials. In addition to dammar and drying oil, GCMS analysis indicated the presence of shellac in some areas. Further analysis by EDS suggested that both bleached and unbleached forms of shellac were present, the former indicated by the detection of significant levels of chlorine – derived from the bleaching process – and corroborated by the fluorescent properties of the different resins on the painting’s surface. Reference samples of shellac from different suppliers were also analysed for comparison. Although the precise restoration history of the picture is not known, the unusual combination of materials, and their localised distribution in different pictorial elements of the painting, suggests the intriguing possibility that Chase may have applied the different varnishes, deliberately exploiting the visual properties of the bleached and unbleached shellacs. The significance of the findings in relation to Chase’s technique, and their implications for conservation, are the subject of ongoing study.