f79r - something written under water ???

[oshfdk]

I doubt it.  It looks like the paint in that area has 100% coverage.  To see whether there are ink strokes under the paint we would need some wavelength that can get through the blue pigment, which is probably azurite (copper carbonate).  But I checked the images of You are not allowed to view links. Register or Login to view. in ultraviolet (365 UV), blue (450 RB), and infrared (940 IR), and in all of them the blue paint seems to be opaque and "black".

It's not guaranteed, but UV probably still has the highest chance of giving more information. As you can see in the image below, the paint from You are not allowed to view links. Register or Login to view. remains dark in all images from UV to IR, but it is a bit less dark in UV, while the ink remains visible in UV and gradually disappears in IR. And while for You are not allowed to view links. Register or Login to view. it's still impossible to discern the ink under the paint in UV, the paint there is obviously much denser if compared with f79r, as seen on the visible light scans.