The color is from vermillion, a pigment newly available in the 12th Century, and a boom time for creation of religious fakes.
Review Geoffery Chauncer for the common view of religious relics in the middle ages...
Pigs bones!
Wrong.
Absolutely wrong! The Shroud has been scientifically studied intensely for several years using modern instruments, and there is NO evidence the image was inked in. Your citing Chaucer when there is modern scientific evidence available?
Vermillion is Mercuric Sulfide... and there is no Mercury in sufficient quantities on the Shroud to be used as a pigment of any kind. If you doubt that determination take it up with the multiple scientists who have done the X-ray Fluorescent Spectrometry, Micro-Elcectronscpectrometry, Pyro-spectrometry, and a host of other tests... that showed there was none. . . as well as other chemical tests that show that the image is composed of a melanoidin chemical substance similar to caramel... and has absolutely no pigment to it at all? Not with Walter C. McCrone who claimed he saw scads of it under his optical Microscope but refused to submit his work for peer-review. McCrone also claimed the blood stains were Red Ocher (Iron Oxide Fe3O2) and Vermillion - yet world class experts in blood and blood derivatives and haemoglobins have stated categorically that it is blood...
Drs. John Heller and Alan Adler concluded that is was actual blood material on the basis of physics-based and chemistry-based testing, specifically the following: detection of higher-than-elsewhere levels of iron in "blood" areas via X-ray fluorescence, indicative spectra obtained by microspectrophotometry, generation with chemicals and ultraviolet light characteristic porphyrin fluorescence, positive tests for hemochromagen using hydrazine, positive tests for cyanmethemoglobin using a neutralized cyanide solution, positive tests for the bile pigment bilirubin, positive tests for protein, and use of proteolytic enzymes on 'blood' material, leaving no residues. Also tests for reflection spectra indicative of bilirubin;s and blood's presence, chemical detection of the specific protein albumin, the presence of serum halos around various 'blood' marks when viewed under ultraviolet light, immunological determination that the 'blood' is of primate origin.Drs. Adler's and Heller's conclusions were confirmed by Dr. Bruce Cameron, whose double doctorate is specialized in Haemoglobin and all of its derivatives... and is the world's foremost expert in that study. The bloodstains on the Shroud... are not paint. They are blood. This is all peer-reviewed, un-refuted, published science.