No text, but a visual code

[Jorge_Stolfi]

To say that the water of Quire 13 is green because it was copied from De Balneis Puteolanis strikes me as mere conjecture, entirely without foundation.

It is at least a possibility.  However, it would require the paints to be contemporaneous with the inked outlines -- which is a conjecture with no supporting evidence, and some evidence to the contrary.  Thus I myself do not believe that the colors were copied from anywhere.

Green is a natural color choice for painting ponds.  (Like for example that one in Washington, DC   )  Hot springs are typically turquoise. Thus painting them royal blue (with ultramarine or azurite) would be just as wrong as painting them green -- and green pigments were cheaper than blue ones.  And outdoor ponds with significant, ahem, fertilizer content will turn green from algae.

what can be stated with certainty is that [the VMS and the De Balneis] have nothing to do with each other.

Why "with certainty"?

If it were only "both have ponds and tubs and naked women", I would agree that it could be just a coincidence.  But most of the women in Quire 13 are obviously bathing in some spa or public bath with multiple separate pools/ponds/tubs. The large tub on You are not allowed to view links. Register or Login to view. has a space at the bottom for heating fire (a hypocaust).  The nymphs on You are not allowed to view links. Register or Login to view. are enjoying shower-like streams. The nymph at bottom left of You are not allowed to view links. Register or Login to view. is supporting herself on a backrest, presumably provided for the infirm or because of slippery bottom.

Moreover, some illustrations in Quire 13 have the same layout as illustrations in some copies of the Balneis. For instance, the "water slide" You are not allowed to view links. Register or Login to view. is similar to illutrations of You are not allowed to view links. Register or Login to view., which was an underground cave reached through a narrow steep descending tunnel. You are not allowed to view links. Register or Login to view., among others, explored this thesis in more detail.

So it is impossible to deny that the VMS artist meant the readers to see "women bathing in a spa".  Then the Balneis is a natural and plausible source for his "inspiration".  

But of course there are may images in Quire 13 that do not fit a "balneological" explanation.  Thus there are good reasons to suspect that "women bathing" was just a cover for some other information, like anatomy.

...hypothesized that Quire 13 deals with plant physiology, with the female figures representing the souls of the plants ... a hypothesis that also had the merit of linking all, or nearly all, parts of the Voynich and giving them a unified meaning.

But that hypothesis would leave the Zodiac section standing out, since the nymphs in the latter would no longer represent stars.

It is possible that the VMS had a unified meaning.  But many manuscripts of the time are compilations of multiple unrelated books.  So "giving the book a unified meaning" is not, by itself, an argument in favor of any hypothesis.

All the best, --stolfi