The argument is not that chalk was used but that the design might have been prompted by chalk images.
All that matters is how the Turin Shroud image looks. It looks very much like a smudge - and like chalk sits on top of the medium. Chalk dust can create ghostly, negative-like impressions. If you press a hand against a blackboard dusted with chalk, you get a faint “positive” image on a dark background. Conceptually, that’s similar to a negative image effect: the more pressure or contact, the lighter the chalk sticks.
Blackboards as we know them (slate or coated surfaces with chalk) were not common in medieval Europe in the 14th century, when the Shroud first appeared historically. But we just do not know what the artist of the Shroud seen. The medieval forgers probably relied on techniques that mimicked a ghostly or ethereal look - the image you might get if you could use chalk dust and get it to stay in place permanently.
Peter Paul Rubens’ art could evoke a reminder of the Turin Shroud image Here’s why:
Dramatic realism and anatomy – Rubens was famous for his dynamic, highly detailed depiction of the human body, often in dramatic poses and with a strong sense of flesh and musculature. The Shroud of Turin also emphasizes the human form in a highly realistic way, showing the contours of the body, wounds, and suffering. Someone familiar with both might notice a kind of shared “intimate corporeal realism.”
Emphasis on suffering and pathos – Rubens’ religious paintings often portray Christ’s Passion with expressive suffering, much like the Shroud’s image conveys pain, death, and solemnity. There’s an emotional resonance that could feel similar.
Use of light and shadow – Rubens’ chiaroscuro (contrast of light and dark) creates sculptural, almost three-dimensional forms, which could remind a viewer of the Shroud’s subtle, almost photographic imprint of the body.
Indirect reference to imprinting – Some scholars note that Rubens’ treatment of bodies sometimes emphasizes an “after-image” of light on flesh—though he didn’t literally imitate the Shroud, the visual suggestion of an impression or trace of a body could feel reminiscent of it.
So while Rubens wasn’t directly influenced by the Turin Shroud, a contemplative viewer might find echoes of its visual and emotional qualities in his work.