Bleedthrough/marks on f96v

[Jorge_Stolfi]

EDIT: and in terms of what i'm seeing regarding the containers, its the lighter areas that are most visible at first.

That may be just illusion -- the darker areas around them make those areas appear lighter.

It has already been noticed that the blue paint has a dark grayish component that apparently does not dry immediately, collects at the edges of the painted area, and then "offsets" (IIUC that is the technical term) onto whatever page it is in contact with it.

So you are saying that, according to your enhanced images, the red paint used in those Pharma containers too can offset onto the facing page.  That seems plausible.

The Painter who applied the colored paints did not seem to be a "professional" like a scribe in a manuscript "factory" would be.  He seems to have used a broad quill instead of a brush, did not clean the instrument properly when switching between colors, and often would overflow or underflow the outline that was supposed to  be painted.  Thus we can expect that his paints were quite a mix of media, and not properly formulated.  

The pigment in the blue paint was the expected one (azurite, a basic copper carbonate mineral), but the microscope images tell me that it was not ground fine enough. And the blue paint may have been water-based but made from leftover oil paint; the dark gray component described above could have been residual oil from that paint.  

According to the lab tests, the more bluish green paint contained copper, but not in the form of a solid mineral powder.  It could have been some organic salt dissolved in water (or turpentine, maybe), rather than a suspension of solid particles.  That would explain why that green color bleeds through the vellum so easily.  The more yellowish green may have been a mixture of that green with a yellow pigment, like ocher or yellow lead oxide.

From its hue, I would guess that the red pigment in the containers is red lead oxide, a solid mineral, finely ground.  (As for the darker brownish red pigment on f67r1 and f67r2, on the other hand, my guess would be hematite, one of the iron oxides.)  

The offsetting you seem to have detected would be caused by defective, insufficient, or decayed binder in that paint.  The binder is the transparent substance that is supposed to hold the solid pigment particles together and to the page.  For water paints, it was (and still is) typically gum arabic, a substance intermediate between sugar and starch.  It will be consumed by molds unless it is kept dry -- which the VMS apparently was not.  High humidity would also soften gum arabic, and a water spill would dissolve it...

If confirmed, that offsetting may tell us that the pages were lost/removed before Wilfrid bought the book.  We expect him to have stored the book properly, in a dry place; whereas the conditions were far from ideal while the book was in the Jesuits' hands.

All the best, --stolfi