French reweaving is one form of invisible reweaving. Unlike other forms of invisible reweaving such as inweaving, it is nearly invisible, without magnification, from both sides of the cloth.
Michael Ehrlich, the owner of a company called Without A Trace offers invisible mending services for expensive fabrics. He explains that inweaving is detectable on the reverse side of the cloth while French reweaving is not. French reweaving was practiced in Europe during the time when it is likely that the shroud would have been repaired in this way before the devastating fire at Chambery in 1534 that did so much damage to the cloth that reweaving was no longer an option.
According to researchers Sue Benford and Joe Marino:
French Weaving, now only done on small imperfections due to its extensive cost and time, results in both front and back side ‘invisibility.’ According to Mr. Ehrlich, French Weaving involves a tedious thread-by-thread restoration that is undetectable. Mr. Ehrlich further stated that if the 16th Century owners of the Shroud had enough material resources, weeks of time at their disposal, and expert weavers available to them, then they would have, most definitely, used the French Weave for repairs . . . the House of Savoy, which was the ruling family in parts of France and Italy, owned the Shroud in the 16th century, and possessed all of these assets.