The illuminations present throughout the manuscript are high quality and Raman microscopy unambiguously identified the presence of seven pigments including vermilion, orpiment, realgar and lead white. The illuminations present throughout the manuscript are high quality and Raman microscopy unambiguously identified the presence of seven pigments including vermilion, orpiment, realgar and lead white. Deterioration of the white pigment in some of the illuminations has occurred and the pigment appears black in these places. This black material was identified as lead (II) sulphide by comparing its Raman spectrum with that of a standard. The conversion of white lead [2PbCO3·Pb(OH)2] to lead (II) sulphide was affected by the presence of sulphur in the polluted atmosphere of late nineteenth century London.