More info that the majority of the blood stains is from blood exudate:
We have shown that [the blood] must have
been taken from the exudate of a clot at a certain point in the clotting process. An artist would
therefore have needed the exudate from the wounds of a severely tortured man, or baboon,
and he would need to take the substance within a 20-minute period after the clotting had
begun, and paint it on the cloth with the serum edges and all the other forensic precision that
we see there.”
www.shroud.com/pdfs/thibault%20final%2001.pdf
all of the medical forensic examinations
of the blood images are in agreement that they were exudates from clotted wounds transferred to
the cloth by its being in contact with a wounded human male body consistent with the historic
descriptions given for the Crucifixion of Christ.That these
are clotted wound exudates is clearly seen in the ultraviolet photographs where every single
blood wound shows a distinct serum clot retraction ring agreeing with the earlier
observations of the pioneers on the major blood wounds as seen directly on the cloth.
https://www.shroud.com/pdfs/adler.pdf
This is in agreement with the body image chromophore being a dehydrated oxidized form of
cellulose and not an artist’s applied iron oxide paint. The reflectance spectra of the blood
marks from the whole cloth and also a near UV-visible microspectrophotometric study of
blood particles from the sticky tapes 29 are consistent with the spectra expected for a traumatic
blood clot exudate. In a more recent study 13 transmission UV-visible spectra of a simulacrum
of a traumatic clot exudate prepared from laboratory chemicals matches these observed
Shroud spectra, but the spectra of a simulacrum of a mineral pigment blood composed of iron
oxide, mercuric sulfide, and gelatin is a complete mismatch.
https://www.shroud.com/pdfs/ssi43part1.pdf
https://debatingchristianity.com/forum/viewtopic.php?p=1118623#p1118623