Molecular Spectroscopy as an alternative for dating Textiles

Abstract

Abstract. Ancient linen textiles undergo with time a slow change reflected in their Infrared and Raman spectra. The recording of FT-IR and FT-Raman spectra, that reveals a disappearance of some bands and appearance of other ones during the centuries, enables a kinetics of degradation to be followed. Here we discuss the results obtained by using dating methods based on two molecular spectroscopy techniques, that is FT-IR and FT-Raman. A set of samples dating from about 3500 B.C. until present has been examined in order to have an adequate set of reference samples. An accurate analysis of the spectra recorded shows that some differences can be attributed to the evolution of some chemical compounds present in the fibers. A linear correlation between a spectral property and time can be obtained. As an example the date of the Shroud of Turin has been evaluated.

X-ray Dating of Ancient Linen Fabrics

“…The comparison with the dating of the fabrics obtained by 14 C confirms that the X-ray dating reported in Table 3 could be a valid and reliable new method to estimate the time when ancient fabrics, which have suffered natural aging, were made because any information about the dating of samples DII, NII, E, and HII has not been used to perform the corresponding X-ray dating. In fact, the obtained X-ray dating can be considered conditioned almost totally by the HR dating of sample FII and almost completely independent by the 14 C dating of the other samples.…”

“…For details about the 14 C date ranges reported in the third column of Table 1, one can refers to previous works [13,15]. To facilitate the comparison with the X-ray dating results, the 14 C dating values reported in the second column of Table 3 have been obtained by expressing the data ranges of the third column of Table 1 as a median value with a [−2σ,2σ] interval. However, it should be noted that, due to the non-monotonic nature of the 14 C calibration curve, 14 C dating very often leads to the impossibility to summarize the data range interval as a median value with symmetric left and right 95% confidence level limits, since the calculated age distribution can be also bi-or trimodal.…”

“…To facilitate the comparison with the X-ray dating results, the 14 C dating values reported in the second column of Table 3 have been obtained by expressing the data ranges of the third column of Table 1 as a median value with a [−2σ,2σ] interval. However, it should be noted that, due to the non-monotonic nature of the 14 C calibration curve, 14 C dating very often leads to the impossibility to summarize the data range interval as a median value with symmetric left and right 95% confidence level limits, since the calculated age distribution can be also bi-or trimodal. Therefore, the 14 C aging time median values reported in Table 3 have to be considered only as equivalent values to allow a direct comparison with the X-ray corresponding dating values.…”

“…Recently, new dating methods of textiles have been proposed based on the mechanical analysis such as breaking strength, Young modulus, and loss factor and on opto-chemical analyses (by FT-IR and Raman spectroscopies) as a function of the age of the fabric [13][14][15]. These new dating methods are possible alternatives to the radiocarbon dating of textiles [16].…”

Determination the Authenticity and Quality of the Goods

“…For the angular range of 30° and the optical dichroic filter more than 850 nm spectral range available for the spectrometer is ~ 35 nm. This range is sufficient for use in Raman spectroscopy [4][5][6]. To solve this problem, an optical filter is used, which consists of a plurality of auxiliary filters, wherein each sub-filter is a dichroic filter with a narrow width in its transmission spectrum wavelength range, and thus, can reach different parts of the optical spectrum.…”