Mr. Vikan is an art historian not a scientist. However the Shroud of Turin is a relic from which has been extracted an immense amount of scientific evidence. One conclusion of the 1978 STURP report is that the image on the Shroud is NOT a painting! This fact alone places the relic outside of Vikan's field of expertise.
The theory that the King of France commissioned the creation of the image found on the cloth is pure imagination for which there is absolutely no historical evidence. Linen cloth of herringbone weave was not even available in the 14th century, and in 1988 the British Museum was unable to find a control sample of that weave dating from the middle ages despite a vigorous search.