Revealing the organic dye and mordant composition of Paracas textiles by a combined analytical approach

Abstract

The object of this study is a wide selection of dyed cotton and camelid samples from an important collection of 2000-year-old Paracas textiles, now at the Museo Nacional de Arqueología, Antropología e Historia del Perú (MNAAHP; Lima; Peru) and at the National Museum of World Culture (NMWC; Gothenburg; Sweden). The threads, chosen as representative of the whole palette, were selected from eighteen different textiles. A combined spectroscopic and spectrometric analytical approach was selected to characterize the organic and inorganic composition of this wide set of samples. In particular, technical photography was used to gain a general overview of the samples, X-ray fluorescence (XRF) was employed for identifying the mordants and mapping the elemental distribution in the threads, while liquid chromatography coupled with diode array detector and with high-resolution mass spectrometry (HPLC-DAD, HPLC-HRMS) were used for characterizing organic dye composition. This study provides fundamental information on the mordants or other inorganic auxiliaries used in the dyeing processes, rarely investigated up to now, and to the varieties of vegetal sources employed in Paracas textiles. The widening of the Andean dyestuff database is highly important not only to acquire knowledge on Paracas culture, but also to ease the dye characterization of archaeological textiles from Peruvian region and South American area in general.

Colors and dyes of archaeological textiles from Tarapacá in the Atacama Desert (South Central Andes)

“…Several variations on the shade (Sample 22) and color saturation for a single yarn (Sample 10) can be attributed to changes that took place after the chemical interaction of the dye with the body uids, during the decomposition of the buried individual. However, we cannot rule out the occurrence of different initial preparations for dyeing, associated with the use of varied aqueous media and/or the inclusion of mordants looking for better xation of the color on the bers [10,54,66,67,68,70]. Thus, the observed differences can be the consequence of technological factors inherent to the dyeing process (fermentation time, length of the exposure of the yarn to the mordants, temperature and humidity during the process, among others), which yield numerous alternatives and combinations amid them, as well as provoked by external agents and factors following the use of the textiles as burial offerings.…”

“…Other colors like yellow, green, white, or brown are less studied [49,50,53,56,64,66,67,69,70]. Only a few of them have widened the analyses of the dyes and focused on the mordants [50,51,54,67,68,70]. Other investigations have approached the painted textiles, a rarely addressed subject [71,72].…”

“…In synthesis, for the pre-Columbian period, studies usually involve the analysis of a few samples, commonly reds or blues, with little information about other colors or shade variations [3,[48][49][50][51][52][53][54][55][57][58][59][60][61][62][63][64][65][66][67]70]. Other colors like yellow, green, white, or brown are less studied [49,50,53,56,64,66,67,69,70]. Only a few of them have widened the analyses of the dyes and focused on the mordants [50,51,54,67,68,70].…”

“…Other investigations have approached the painted textiles, a rarely addressed subject [71,72]. From an analytical point of view, they have been applied chromatographic or spectrometric techniques (CG-MS; HPLC; LC-DAD-MS; DART-MS, between others), which albeit sensitive are destructive methods [3,[48][49][50]53,54,[56][57][58][59][60][62][63][64]66,70]. SERS spectroscopy analysis was applied in just four cases to analyze in two studies the archaeological textiles from Peru and, in the other two, samples from northern Chile [55,61,65,69].…”

“…Every garment or ornament textile is unique; hence its study must privilege the use of non-invasive (or minimally invasive) and non-destructive analytical techniques. The identi cation of the bers and the colorant raw materials used for dyeing constitutes one of the routes for achieving a better comprehension of textile technology and production [10,51,[66][67][68]70]. Although multiple analyses are available, a better understanding of the technological processes involved can be reached through the combination of multiple analytical techniques.…”