You have to remember that the Shroud as we see it today is a positive of the Shroud's negative image. What you actually see on the Shroud is not what we see in the photographs. What we see could only be seen in the past 117 years after Secondo Pia took the first photograph of the Shroud. Even photographs that show the Shroud as it really appears are enhanced to darken the image. . . which is very evanescent.
One would think that questions of appearance could be cleared up quite neatly by transforming this into a positive. If it is supposed to be an “exact picture of Jesus.” Come on 117 years of research, where is the solid sculpture which would result? Then it can be judged on whether it plausibly meets the scriptural criteria.