Date of Award


Document Type


Degree Name

Master of Historic Preservation (MHP)


Historic Preservation

Committee Chair/Advisor

Dr. Stéphanie Cretté

Committee Member

Lisa Arslaner

Committee Member

Kate Dieringer

Committee Member

Virginia Theerman


Identification methods for the analysis of indigo dye within textiles have been compiled in multiple studies. Though few examples demonstrate chemical analysis and phase separation as a technique that can assist in the identity of the dyestuff. The inclusion of nontechnical methods, techniques that require little knowledge of chemistry and can be completed without the assistance of high-tech machinery, can contribute toward these efforts. The goal of this thesis was to provide a simple testing procedure where eight historic textile samples dating from the mid-eighteenth to the mid-nineteenth centuries were subjected to chemical analysis and phase separation to determine the presence of indigo for The Charleston Museum. A reducing solution of 1.25 g sodium hydroxide, 1.25 g sodium dithionite, and 25 mL deionized water was combined and introduced into Eppendorf tubes containing the historic samples to facilitate a chemical reaction. The tubes were added to a water bath at 40 C for 2-3 minutes to assist in the reaction, an observable color change that could be recorded as part of phase 1. Phase 2 consisted of adding ethyl acetate following chemical analysis to bring about phase separation, where the internal components would separate and result in two layers. Provided phase separation occurred, the top layer was extracted, and the color was noted. Findings suggest that these methods are relatively effective in determining the identity of indigo dyestuffs within historic textiles since six out of the eight samples tested were found to be positive for indigo. The data recorded in this thesis can be used to assist future museum professionals, and conservators when examining historic textiles and determining best methods of indigoid dye analysis.



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