Yes, because I’m providing the background information on the bas-relief technique and a summary of what we’ve discussed so far.
With the intro already given, let’s discuss the lack of imaging on the top of the head…
First of all, the lack of imaging is simply a feature of the shroud that needs explaining by whatever technique is theorized. And it is only one feature that needs to be explained out of the dozens of features.
A bas-relief could explain the lack of imaging between the ventral and dorsal images of the head, depends on how it was depicted. If it was a single cloth that wrapped a body and it was painted in one shot, it would not make any sense. In that case we should see a continuous imaging over the head. If it was painted twice, first painted with the ventral side, then the cloth relaid with a gap between the tops of the head, then painted with the dorsal side, then this would make sense. But, this does not automatically mean therefore the bas-relief technique is the only method that is viable. Again, we need to compare all the theories and see how many of the features they do account for, including the head gap.
There are two broad categories of imaging theories – artistic (involving an artist) and non-artistic (does not involve an artist and is from the body itself). Pretty much all artistic theories can account for the head gap. Most non-artistic theories would not account for the head gap. In particular, any theory that involves gas emanation from the body would most likely not have a head gap. Also, any theory that involves radiation from the body would also not have a head gap. There is one radiation scenario that could account for it if the radiation is not emitted in all directions, but only radiated like a laser in a single direction. I don’t like that theory because it has an ad hoc nature to it of proposing radiation being emitted perfectly vertically in a single direction instead of omni-directionally. Another theory that explains the head gap is the theory from the head of STURP, John Jackson, has proposed, the cloth collapse theory. Instead of radiation going out of the body, the cloth collapses into the body and the image is formed during body contact. This would explain the head gap and many other features as well.