UCLA

This research aimed to expand the scholarship of laundry bluing histories and technical considerations for analytical characterization. To illustrate the complexities of studying this material in cultural heritage collections, the author also analyzed blue colorants in a group of objects from the Michael C. Carlos Museum’s African Art Collection. The use of laundry bluing as a source of pigments for artworks has been a relatively common practice worldwide, and was often closely tied to colonial enterprise. Bluing recipes varied, with the blue colorants ranging from smalt, indigo, Prussian blue, aniline blue, and synthetic ultramarine. The simplest recipes were often just pigments suspended in water, but other materials, such as binders or fillers, were often added to enhance the working properties of the product. The characterization methods for differentiating bluing recipes assessed included: X-ray fluorescence (XRF) spectroscopy, Multi-band Imaging (MBI), Fourier-transformed infrared (FTIR) spectroscopy, chemical testing, polarized light microscopy (PLM) and fiber optic reflectance spectroscopy (FORS).