First actual assertion.
Five minutes googling and reading on "shroud of turin blood" led me to this.
Seems to make utter mincemeat of McCrone --
just a few examples...
McCrone did not use controls for old blood
McCrone's description of the characterization of particles changed over time (1980 he identified them as iron oxide and in 1996 as red ochre)
McCrone performed some of his tests (e.g. birefringence) on particles attached to a matrix which would itself interfere with his tests
Some of McCrone's work has been unable to be duplicated by other groups working independently on the same samples.
Try reading the whole thing.
Cheers!
McCrone did two of the tests done in 1973, and he either did or did not get the ‘blood’ into solution before proceeding with the benzidine and sulfuric acid tests; if he got the ‘blood’ into solution, even as the Italians did not, then McCrone could not have honestly said “I find it impossible to fault the [1973] work.” I conclude that the other possibility is the correct one: McCrone did not get the ‘blood’ into solution, in which case, his negative results with the two tests, like the 1973 results, are meaningless.
McCrone performed the phenolphthalein test, which is much more difficult to do than the benzidine test. 54 Since McCrone could not even properly handle the benzidine test, I conclude that he could not have properly done the much more complicated phenolphthalein test, in which case his obtaining negative result(s) with the latter is worthless. The Takayama and Teichman tests yielded McCrone negative results, yet since they are so insensitive, negative results with them does not mean blood is absent
Fischer, writing with the assistance of Nickell and Mueller, alleges that they found that hydrazine also dissolves “tempera paint composed of the pigments and medium identified by McCrone” and produces a pink hemochromagen-like color, thereby suggesting that H&A’s hydrazine test is given to false positives. 133 I strongly suspect that the medium referred to is a proteinaceous tempera made from animal collagen (the sources being muscle, skin, tendons, bones, cartilage, etc.), 134 and that the pigments referred to are iron oxide, vermilion/ mercury-sulfide, and rose madder. Since McCrone believes he saw merely “a few particles” of rose madder pigment, 135 since he thinks that “nearly all of the colored particles on the [Shroud] tapes are red ochre,” 136 and since McCrone’s writings give scant mention to rose madder, I fail to see the basis for Fisher et al.’s viewing rose madder as being somehow significant to discussions of what the ‘blood’ is. Parenthetically, the color “madder” was derived from the root of the field plant Rubea tinctorum; a chemical substance in the root called “alizarine” is responsible for the red color of madder.
Those are quotes from pages 4 and 10.