Re; Update- I would also guess Mr. Januszczak is not aware of the Christ portrait found in the catacombs in Rome dating around 300AD. Which by the way also bears a striking resemblance to face seen on the Shroud. Although dated to 300AD some believe it may be of an earlier date, possibly even the 1st century and quite plausibly painted by someone whom actually had seen Jesus.
Pictured: Bearded Christ from the catacombs of Commodilla ca. A.D. 302-303 at the time of the Diocletian persecutions.
So had the “Middle Ages invented this suffering, bearded Christ and then somehow found a clever way to imprint the image on the fake Turin Shroud,” as Januszczak stated it or had the ‘Middle Ages discovered this suffering, bearded Christ imprinted on the image on the real Turin Shroud?’
You decide. But I think the evidence is overwhelmingly in favor of discovered. Moreover, the style shift throughout the Middle East from Syria to Egypt was sudden and complete. I doubt it was because of creative invention. Rather, it was probably a compelling discovery.