Can you please link us the the site where this article appeared? I am particularly interested in the identity of the mystery artist.
I'd also like to read Pope Clement VII's official statement, and get an explaination on how he was able to make it in 1389, when he sat in the Papal seat from 1523-1534. And before you try to claim that the name was a typo, Clement VI died in 1352.
The fact that the naysayers feel the need to lie and make things up to discredit the Shroud is uncontrovertible proof that they are unable to prove that it is fake. I'll leavc their motives for wanting it to be fake for others to speculate.
Who was Pope in 1389 depends on who you ask. Urban VI is considered the Pope today, but Robert of Geneva (Clement VII), an "antipope" or rival claimant for the papacy, had a strong claim (though Nickell errs by simply calling him "the Pope"). Information on Robert of Geneva can also be found in the Catholic Encyclopedia.
The results of the microanalysis and carbon dating tests Nickell describes have been challenged by those who accept the Shroud's authenticity on faith, but have yet to be scientifically invalidated.