S&V - Pages 123-124
...other analyses carried out by the chemist Walter McCrone however made all the light on what contained really the coloured linen fibres. From 1980, this specialist in the ultramicroanalyse published three scientific articles (in particular in the Microscope Magazine) on the subject.

He submitted the samples to a series of tests specific to blood. All proved to be negative. On the other hand, he discovered on the level of the shroud images (on the yellow layout of the man body and on its stains of « blood »), some iron oxide particles, in other words red ochre, but also traces of another dye: the rosy of garance. The brown flows contained also vermilion, or sulphurizes mercury, another pigment used in particular by the medieval painters. Lastly, he isolated collagen, a binder used usually in the form of animal gelatin to fix the colors...

These substances, absent of the blank zones of the linen, alone explain the presence of the bilirubine, the porphyrin and the albumin.

VSD - Page 26
...the American chemist McCrone starts again the polemic. Having found on the shroud some microscopic and isolated traces of pigments as well as the presence of proteins, index of a layer of pictorial binder, he affirms again that the shroud is a painting.

But the researchers of STURP (Shroud of Turin Research Project) show quickly that McCrone made a gross error in his analyses, then they discover the exact nature of the image, not due to pigments but to a surface oxidation (light reddening) of the cellulose at the tops of the fibrillae of the linen cloth. But the thesis of painting will continue to be included regularly in the media, and that it is still today advanced by the sceptics.