Welp, if the docent at the Sistine is full of it, she said he hired six painters and just managed it. So I don't know.
And I agree with you, they are all orig. but it is the way they classify it. They brush over a sketch where as an orig. is not. So they call that a semi. and the px is different, about half.
To me, how do you know it was painted over a sketch? I would never know.
That is like buying a $200 bottle of wine or a $2000 bottle or a $20,000 bottle, you get to a certain point where the $250 bottle tastes just fine.
You buy the $20,000 bottle just to say, "I can". But that is not smart.
.