MUST READ: Image Formation by Denis Mannix. These are the last two paragraphs:
This explanation of the image formation indicates that any corpse covered, while it was still warm, with a linen shroud that had had been treated with soapwort would produce a similar shroud image in the initial period after burial. However, after a sufficient passage of time, the image would be obliterated by the mass of amines arising from all parts of the body. In the case of the Shroud we have a naked, badly damaged and traumatised body being wrapped in high-quality linen which must have then been separated from it in the early stages of the image formation ie. before the stage of image obliteration.
In this work Rogers and Arnoldi have been able to show that the image could have been formed through a sequence of well known scientific steps and without any mystery or unproven scientific theory. Their hypothesis provides an explanation for every aspect of the image that has been noted