Recent research conducted in Italy and led by Professor Giulio Fanti of the University of Padua has led to the discovery of some innovative, new methods of dating flax, the substance used to make linen fabric. It had already been shown that some spectroscopic and mechanical properties of cellulose, which is the main constituent of flax, slowly change due to the cellulose gradually deteriorating with increasing age. Giulio Fanti believed that if these changes could be detected and measured, then they may provide the basis of an alternative to radiocarbon dating.
This research eventually produced three new methods of dating minute fragments of linen fabric based upon measurements made using:
Fourier Transform Infrared Spectroscopy (FT-IR) is a method of analysing material by radiating it with infrared light. Some of this infrared light is absorbed and measurements of how much light is absorbed at each wavelength can be made by analysing the spectrum produced by the material. These measurements reveal details about the molecular composition of the material.
RAMAN spectroscopy is a similar technique to FT-IR but this method uses a high intensity laser source instead of infrared radiation. The irradiated material scatters light at different wavelengths and intensities and its molecular composition can be ascertained from an analysis of the resulting spectrum.
Some mechanical properties of flax fibres, such as breaking strength and elasticity, also deteriorate slowly with age. A highly sensitive, purpose-built tensile machine was designed and developed by Giulio Fanti’s team to measure these properties using individual fibres. This machine was able to measure forces to a resolution of two micronewtons (equivalent to a load of 0.1 grams) and elongation to a resolution of 0.1 micrometres, which is a fraction of the diameter of a strand of silk from a spider’s web.
The research team obtained several samples of new and ancient flax textiles of known age. Detailed examinations revealed evidence of excessive contamination or damage in 30% of these samples, leaving thirteen which were considered to be suitable. Three of these were samples of modern linen fabric but the rest dated progressively older, with the most ancient being from a flax mummy wrapping from the period 3000-3500BC. When the selected samples were tested using these three techniques, the resulting measurements showed a clear relationship with the sample age. The results of these tests were used to calibrate mathematical equations that could reliably calculate the date of a sample from values obtained using each of the three methods.
These three techniques were then used to date material taken from the Shroud, with the following results:
300 BC ± 400 years
200 BC ± 500 years
400 AD ± 400 years
These new dating techniques were clearly at an early stage of development, which is one of the reasons for a camparitively high margin of error on the test results. However, they all produced date results for the Shroud which were many centuries earlier than that produced by the 1988 radiocarbon test. The mean date of the three tests was 33 BC ± 250 years, with a 95% confidence level, a result which is entirely compatible with the belief that this linen cloth was the burial Shroud of Jesus Christ.
Performco Ltd. Town Hall, Penn Road, Beaconsfield, Bucks HP9 2PP
Copyright © Performco Ltd.