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A very dry 600 years...

Posted: Mon May 04, 2020 9:32 am
by proto57
I was reading the McCrone report for the umpteenth time, with a focus on the green paints. It turned out that my initial reason became moot, but I was nonetheless still curious about the designated composition of the greens. The McCrone report states that the green is a "copper resinate". Page 4:

"GREEN PAINT: The green paint was tentatively identified as a copper and copper-chlorine reisnate, most likely produced as a salted copper corrosion product".

The problem with this is that by the 17th century, it was discovered that copper resinate would darken and discolor, turning brownish and even black. This is because the copper would turn to copper oxide, which is brown, not green.

Artists became aware of this, and came up with methods of avoiding the problem, such as encasing the green paints in varnish. But the Voynich's paint is not in a varnish. Exposed to light and/or air, over time, it should have discolored. The key being "over time".

Wikipedia :

"Copper resinate, made from verdigris by boiling it in a resin, is not lightfast, even in oil paint. In the presence of light and air, green copper resinate becomes stable brown copper oxide."

One might argue that the green pigments in the Voynich were protected from air, and therefore, from oxygen. I would reject this contention, for even if locked in a trunk for almost six centuries, the book clearly was not flattened with any force, as the leaves are very uneven, and air could easily circulate to most of the pigmented surfaces. But the greens are bright and colorful, which fits with the work being created more recently than six hundred years ago. But then I read a wonderful thesis which delves into this issue in great detail:

"Discoloration of a Green Pigment in Tintoretto's Allegorical Figure of Spring and Analysis of the Chemical Properties and Stability of Copper Resinate", by Sarah Wells Conner Horn, Summer, 2016: ... istry_etds

Page 16: "Copper Resinate- Green- Copper(II) abietate- Mixture of verdigris and Venice turpentine"

Page 18: "In this thesis, I will closely examine Tintoretto’s easel painting, Allegorical Figure of Spring, which appears to have changed in color from a spring-like green to dark brown over time", and, "Copper resinate, a popular Renassance pigment, has a well-documented record of discoloration from green to brown, but its presence must be confirmed".

Page 62, "Because the patterns and circumstances of browning are so variable, it has been difficult to elucidate the mechanism or causes of the discoloration." She then goes on to discuss several theories as to why copper resinates discolor, such as the medium they are mixed with, exposure to oxygen and other gases, and UV light (the cases in which the greens "protected" by a frame in a painting are less changed).

After the author studied and tested her own copper resinate formulas, she concluded that it is exposure to water and/or humidity which causes the darkening of this pigment in old works. Since we cannot know the level of humidity the Voynich was stored in, I cannot argue that the copper resinates "should" be brown. Of course, in my experience, no matter what the cause of the darkening of copper resinate, it would be said that "we know" the Voynich was not exposed to them, because "we know" the Voynich is old, and the green is fresh and bright. Or if it darkened in air, it would be said either that the Voynich was sealed in an airless trunk, or the green was "added later". I mean, no matter what is found, in the context of genuine 1420 European: if it is damning it is excused; and if it is supporting it is heralded.

But still I have to point out 1) the observations of many that the Voynich colors, for the most part, are very bright and fresh looking, and 2) it stretches my credibility that the very vulnerable form of green used in the manuscript happened to avoid, in its supposed 600 year life, any periods of high humidity at all. No proof, not even evidence, of course: But just another, to me, suspect feature of the Voynich, which is both far from alone, and also, fits well with a modern forgery hypothesis, and once again, does not argue against it (as it would, if the greens had turned brown, showing age).

Re: A very dry 600 years...

Posted: Mon May 11, 2020 5:28 pm
by Keith
Hello Rich,

Logically light, particularly UV is responsible for the greens discolouring. There are 1000s of MSS on line with plenty of green colour. Here is just one example, about 100 years older than VMS, just look at this
from J P Morgan in NY.

Its clear from the above I find it incredibly unlikely that WMV would tie up resources for months faking an unknown book when he had 1000s of books to catalogue, crate up and deliver to waiting wealthy collectors in London and New York. If he needed to create a fake surely a one page map would have been a better option. Would a master forger of art works create a fabulous "old master" with an unknown name?

I like to think that if someone offered you a clock claimed to be 400 years old you would know if it was a repro. Surely you would feel the age.

Thank you for creating the site.


Re: A very dry 600 years...

Posted: Tue May 26, 2020 7:01 am
by proto57
Hi Keith: Thank you for the input and feedback... and sorry for the wait on the post approval, I had the permissions set wrong on this sub-forum.

All the best,