Shroud of turin carbon dating problems
As the starting point, assume that the "true" age of the Shroud is 2000 years, and further accept that the measured radiocarbon age (about 600 years) is a good estimate of the radiocarbon that was present in the samples measured. Suppose that the bioplastic layer began at the time the cloth was made (2000 years ago) and has been growing uniformly ever since.Then the carbon in the layer will have an average radiocarbon age of about 1000 years. Suppose that the Shroud remained growth-free right up to around the middle of the 20th century, when some process, or contamination, started the layer growing.This is not negligible, and if regarded as a uniform layer around a cylindrical thread it represents an increase in the thread thickness of around 12%.
As an archaeologist with 25 years of experience using C14 for the dating of excavated samples, I know what most archaeologists do when C14 produces a date which conflicts strongly with other evidence from a site : 1) run more dates on different samples from the same context, and then 2) put the aberrant dates down to some unidentified problem (usually in a footnote to the site report if mentioned at all).The matted appearance would be obvious to the most cursory inspection, and clearly does not describe the Shroud.Furthermore, the increase in weight of the Shroud would be quite apparent. These scenarios are simplifications, and more complex situations can, no doubt, be dreamed up.The causes of these phenomena are known, but in many other cases anomalous dates have not been satisfactorily explained.Caution is certainly in order when C14 results conflict with the lines of interpretation indicated by other evidence.