Here is what a forger had to do:
1. The forger first painted the bloodstains before he painted the image.
2. The forger integrated forensic qualities to his image that would only be known 20th century science.
3. The forger duplicated blood flow patterns in perfect forensic agreement to blood flow from the wrists at 65° from vertical to suggest the exact crucifixion position of the arms.
4. The forger "painted" the blood flows with genuine group AB blood that he had "spiked" with excessive amounts of bilirubin since the forger knew that severe concussive scourging with a Roman flagrum would cause erythrocyte hemolysis and jaundice.
5. The forger "plotted" the scourge marks on the body of the "man in the shroud" to be consistent under forensic examination with two scourgers of varying height.
6. The forger also duplicated abrasion and compression marks on the scourge wounds of the shoulders to suggest to 20th century forensic examiners that the "man in the shroud" had carried a heavy weight following the scourging.
7. The forger, against all convention of medieval artistry, painted the body he was "hoaxing" as Jesus of Nazareth, nude to conform to genuine Roman crucifixions.
8. The forger, as the forensic genius he was, illustrated the nails of crucifixion accurately through the wrists rather than the hands as in all other conventional medieval representations. He also took into account that the thumbs of a crucified victim would rotate inward as a result of median nerve damage as the nails passed through the spaces of Destot.
9. The forger was clever enough to "salt" the linen with the pollens of plants indigenous only to the environs of Jerusalem in anticipation of 20th century palynological analysis.
10. The forger was an artist who surpassed the talents of all known artists to the present day, being able to "paint" an anatomically and photographically perfect human image in a photographic negative manner, centuries before photography, and be able to do so without being able to check his work, close up, as he progressed.
11. The forger was able to paint this image with some unknown medium using an unknown technique, 30-40 feet away in order to discern the shadowy image as he continued.
12. The forger was clever enough to depict an adult with an unplaited pony-tail, sidelocks and a beard style consistent with a Jewish male of the 1st century.
13. The forger thought of such minute details as incorporating dirt from the bare feet of the "man in the shroud" consistent with the calcium carbonate soil of the environs of Jerusalem.
14. This forger was such an expert in 20th century biochemistry, medicine, forensic pathology and anatomy, botany, photography and 3-D computer analysis that he has foiled all the efforts of modern science. His unknown and historically unduplicated artistic technique surpasses all great historical artists, making the pale efforts of DaVinci, Michaelangelo, Raphael and Botticelli appear as infantile scribblings.
If the Shroud of Turin is a forgery of the 14th century, as the radiocarbonists claim, and not a genuine artifact of the 1st century, all of these qualities of the purported medieval "forger" must be accepted. If the Shroud was "forged" it would have to have been painted.