One more thing..I see repeated references to Raphael being impressed with the work of Durer and wanting to try it for himself.
EXCEPT..the references are talking about Durer’s engraving and Raphael had his buddy Marcantonio set about honing the craft of ENGRAVING.
Here is something else, there is a book out that translates letters and such from Durer.
NOWHERE is there a reference to Durer receiving a transparent painting from Raphael. It does , however, bring up something that happened after Raphael’s death.
He sent some engravings via Thomas who then sent them by someone else and that person was suppose to send some of Raphael’s things. The author of the book notates that it is probably some engravings.
HIGHLY unlikely it would have been a valuable self-portrait of Raphael - when Durer didn’t get even get back his own painting.
The life of Albrecht Dürer of Nürnberg: with a translation of his letters
But let’s say it was a self portrait of Raphael. It would have happened AFTER HIS DEATH...not part of some exchange in letters between the two.