New video: "Is the Voynich Manuscript fake?"

[Jorge_Stolfi]

The issue with the Vinland Map titanium was, as you say, that it was in the modern anatase form.

Let me share what I know of the chemistry involved.

The iron in iron-gall ink comes from "green vitriol" or iron(II) sulfate FeSO4, a soluble clear light-green crystalline material.  Historically, it and "blue vitriol" (copper sulfate, CuSO4) were collected from old iron and copper mines whose ores were sulfides of the metals (pyrite, chalcopyrite, bornite, etc.).  Water with dissolved oxygen percolating through the rocks turned those sulfide minerals into sulfates.  Sometimes that water pooled on the floor of the mines and evaporated, leaving crystals of the sulfates behind.  ("vitriol" comes from the Latin for "small glass").

Ferrous sulfate can also be made by dissolving iron or steel metal (but not iron ore or rust) with sulfuric acid.  By 1400 European alchemists had already learned how to make sulfuric acid; but the usual process was distilling it from green or blue vitriol.  Thus I don't think it was normally used to make green vitriol for iron-gall ink.

But, either way, green vitriol should not contain significant amounts of titanium, because the process that formed it from sulfide ores would not form any soluble salt of titanium. In fact titanium salts easily decompose to form titanium oxide and other insoluble compounds.  Anyway the pooling and crystallization of the green vitriol would tend to exclude impurities, either solid or soluble.  

Thus iron-gall ink should not contain any significant amounts of titanium.

The titanium that was detected in the Vinland Map was titanium dioxide TiO2 in a specific crystalline form (anatase) that began to be produced synthetically in the early 1900s.   It is a white insoluble pigment, but the crystals are so small that they stay in suspension in usual ink formulas, like the fat droplets in milk.  

Colored inks and paints can be made from soluble dyes or from solid pigments.  The former produce transparent films whose hue changes with thickness in a characteristic way. Like, "yellow" dye ink would change from colorless to light greenish yellow to golden yellow to orange to red and ultimately to black.  Moreover, if the substrate is colored, its color will show through the ink or paint.  In particular, if the substrate is black, the result will look black, no matter how thin or thick the coat is.

Inks and paints based on insoluble pigments, such as tempera and watercolor, instead form semi-transparent or opaque films whose color depends on thickness in a very different way.  Like, red watercolor will change from colorless to pastel pink to full red, when the surface is entirely coated with the pigment particles; and then will remain the same red color no matter how thickly it is over-painted.  And while the color of the substrate will show though thin films, the saturated color will be the same on any substrate, including black.

For those reasons, solid pigment inks are generally better for art and writing than soluble dye ones.  But they are expensive to produce, since each color comes from a specific mineral that, even when produced synthetically, must be ground and sifted to obtain grains of the required small size.  Today, common opaque inks and paints are often based on soluble dyes with titanium white added.  This makes them behave like solid pigment inks. Namely,  when the thickness of the paint or ink exceeds a certain point, the painted surface will be entirely covered by titanium white particles coated with a layer of dye with fixed thickness -- hence with a fixed color.

On the Vinland map, the titanium white was probably added by the forger to his ink formula in order to make the traces and/or their "halos" come out with the right hue and opacity.  

But while McCrone detected some titanium in the X-ray fluorescence spectrum in some particles of two samples of VMS text ink (17 and 20), the X-ray diffraction spectrum saw no sign of titanium white.  The former technique only detects which elements are present, with no information about their chemical state.  The latter measures the spacings and angles of atom layers in crystalline materials, which can identify crystalline pigments (such as azurite or titanium white).  

Neither method can positively identify iron-gall ink.  Instead, it seems that McCrone goes by elimination: if it it is dark writing ink, has iron, but has no crystalline pigment, they would say "iron-gall ink".  This is normally a safe bet, because the only reason to write something on vellum instead of paper was the desire to make it water- and wear-resistant for many decades; which could only be achieved by writing in iron-gall ink. 

This deduction is so dependable that, when McCrone examines dark writing ink and finds has no crystalline pigment and no iron, they will say ... duh ... "iron-free iron-gall ink".

The honest thing would be for them to say instead "iron-containing" (or "iron-free") "dark ink of indeterminate composition".  But that would not look good on the report, would it?

And in fact there are many signs that the VMS text and drawing ink was not iron-gall ink.  It does not seem to have any of the properties that made iron-gall ink the only right choice for writing on vellum.  Including its color in the infrared scans...

An that could explain why McCrone detected titanium, but not titanium white, in sample 17.  If the ink is not iron-gall, the most plausible alternative is an ink based on some common insoluble brown pigment, such as sienna or roasted ocher, with a binder like gum arabic.  Unlike green vitriol, these minerals often contain titanium as impurity.  Such an ink would have all the "qualities" that we can see in the VMS: brown color instead of purple-black, wears off easily, washes off completely even after many decades, is transparent to 950 nm infrared light...

All the best, --stolfi