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The VMS ink is NOT iron-gall
- The VMS ink is NOT iron-gall
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RE: The VMS ink is NOT iron-gall
Aga Tentakulus > 3 hours ago
When I look at Lisa’s UV image and compare it to yours.
The writing is visible everywhere—in the water stain, near the possible chemicals, and, hmm, even where there’s nothing.
It’s visible in all three places. I can even see it without UV light.
When I look at the writing on the other side, I don’t see any pigments in the ink or on the parchment. The ink is dissolved and isn’t pigmented.
That’s why the ink has migrated through the parchment due to the moisture. -
RE: The VMS ink is NOT iron-gall
Jorge_Stolfi > 2 hours ago
(3 hours ago)Aga Tentakulus Wrote: You are not allowed to view links. Register or Login to view.When I look at the writing on the other side, I don’t see any pigments in the ink or on the parchment. The ink is dissolved and isn’t pigmented.
You can't tell that at this magnification. Not even in the higher magnification images included in the McCrone report (~180 pixels/mm). The solid pigment particles in watercolor or lampblack ink/paint are way too small to be distinguished in those images.
But I think that the particles of the blue pigment (azurite) can be seen,just barely, in the McCrone images of the blue paint:
Those white and dark blue dots in the blue-painted area could be individual particles of the mineral, rather coarsely ground. Which would be consistent with the general "improvised" or even "home-made" nature of the paints (and of the painting instrument -- apparently not a brush but a broad-tip quill pen).
On the other hand, I suspect that the bluish green paint used on most of the leaves may have been a soluble dye, seeing how strongly it shows on the other side of the vellum:
McCrone did not identify that green paint; they only determined it contained copper and was not crystalline, hence not malachite or other mineral, and guessed it would be a salt of some unidentified organic acid (a "resinate" in their words).
My wild guess is that it is copper stearate, which can be made by mixing soap with a copper salt like blue vitriol. It is insoluble in water but should be soluble in turpentine or any other solvent used for oil paints. And it seems that organic solvents like turpentine, unlike water and water-based inks, can penetrate the vellum. I gather that vellum is made slightly water-repellent precisely to prevent ink "flaring" and bleed-through.
The yellowish-green paint seen on the first image above may be a different pigment altogether, or a mixture of that bluish-green paint and some yellow pigment.
By the way, the shiny nearly-black ink at the center of the second image is what I believe iron-gall ink should look like. I could contrast it to the much fainter yellowish-brown trace below it. But that would take me into the forbidden BEEP territory...
All the best, --stolfi -
RE: The VMS ink is NOT iron-gall
eggyk > 1 hour ago
I'm slightly confused. In the interest of actually aiding in this conversation, answers to the following would be helpful:
-Is there a certain way IGI should or should not get absorbed/ bleed through the parchment?
-Is it normal that IGI soaks through to the other side of a sheet of parchment, should it only happen in certain circumstances (such as excess moisture)?
-Should IGI rub off onto pages it is facing once dry?
-When IGI soaks into the vellum, is it really "dissolved", or is it the same chemical structure within a porous material? (like water in a sponge is not dissolved)
If we know the answers to these we can potentially test some hypotheses using image analysis of different pages.
(10 hours ago)Jorge_Stolfi Wrote: You are not allowed to view links. Register or Login to view.
(Yesterday, 09:57 PM)oshfdk Wrote: You are not allowed to view links. Register or Login to view.The following article shows iron gall ink as nearly transparent in 900-1500nm: ... Quoting from the article:
Quote:The underdrawing materials that become transparent, and are not therefore visible, include red Conte crayon, charcoal and iron gall ink.
Yes, but that is what the article I quoted said too: iron-gall ink remains opaque up to 1200 nm, while ocher becomes transparent by 800 nm. And the VMS ink is already transparent before 940 nm (the longest wavelength used in those images).
All the best, --stolfi
The crux of the issue here is that we have two different studies now with two wildly different ranges for the transparency of their specific IGI. In that second study, it says "nearly transparent in 900-1500nm". Your images clearly also do not show fully transparent IGI, even at 940nm; some of it is still visible. Therefore our observations on the VMS ink is consistent with it appearing "nearly transparent" at 900-1500nm.
Furthermore, the existence of two ranges in two studies implies the possibility of more ranges for more types of IGI in others. The exact composition of the ink clearly matters in this regard.