Beige stain on 93r

[Jorge_Stolfi]

Looks like any kind of later water damage.

Well, the "coffee" stain has exactly the same color as the "flower".  Even on the multispectral scans.  For example, it is as dark as the leaves under UV and blue, lighter under amber and red, and nearly invisible under 870 and 940 nm infrared (whereas the leaves are still dark). As expected from ocher paint.

Or are you referring to the water stain on the top margin (J,K)? Yes, that one could be just a water stain from any other time.

All the best, --stolfi.