Why the rosettes image may not be a map at all

[-JKP-]

Well observed, Wladimir.
Hmm, the glimmer continues a little bit below the spire, so it's separate from the yellow paint.

Might this ne the result of the 'clear white paint' mentioned in the McCrone report? This was based on egg white, so presumably it would provide some shine...

You're quite right, egg white might provide a slight shine that could be picked up by a scanner.

Here's another "shiny" spot in the center rosette that resembles an off-white splotch of paint (perhaps white mixed with a little of that pale amber color):