Orange for gold? Arsenic sulfide glass on the V&A Leman Album

The so-called Leman Album comprises over 90 designs for woven silks drawn and coloured in the early 18(th) century by James Leman, a designer and weaver operating in Spitalfields, East London. The designs are characterised by a very broad palette, which was investigated at the Victoria and Albert Museum using exclusively non-invasive techniques. Notably, a bright and vibrant orange material was very popular with Leman, who used it extensively. X-ray fluorescence tests showed that arsenic and sulfur were the predominant elements in the orange areas. A mixture of bright red, orange, and yellow particles could be seen under high magnification. These different types of particles were identified by Raman spectroscopy as arsenic sulfide glasses, that is artificial materials used as substitutes for naturally occurring pigments such as orpiment and realgar. In a few cases, a small amount of mineral orpiment was also detected. Such an extensive use of this artificial pigment is not commonly recorded in the literature. Because in a few of the handwritten comments that Leman made on the reverse of his designs he clearly stated "the orange colour to be gold," we can reasonably hypothesise that this orange pigment was used for the parts that were intended to be woven with gilded metal threads. Textile designs made by other pattern-makers working in Spitalfields in the same period as Leman were also analysed for comparison. Arsenic sulfide glass was detected in most of the orange areas, confirming that this material was certainly popular amongst silk designers of 18(th)-century London.