[split] Jorge's Retracer Thread: darker ink, retracing of text and drawings

[Jorge_Stolfi]

you are asking people to stop believing the images altogether.

Not at all. On the contrary, I am urging people to look carefully at the images and see what is actually there -- not whet they assumed should be there.

Do you have a quantified rating system of how likely something is to be retraced?

Unfortunately not. Not completely, at least.  On the multi-spectral images one can distinguish a "dark" ink that remains somewhat opaque in the infrared images, and a "light" ink that is mostly transparent there.  (According to You are not allowed to view links. Register or Login to view., that would be consistent with the former being iron-gall ink, or containing some of it, and the latter being a paint made from ocher or some related pigment.)  

And on practically every page one can see bits of writing and drawing that are faded almost to invisibility.  That is what I believe all the text and drawings looked like when the owner decided to have the book restored.

But different ink color and density is only one criterion. By itself, it does not distinguish between "late" retracing, pen "recharging" by being dipped into the inkwell, and the original Scribe himself going back and retracing some glyphs that he wrote moments before. Other evidence of retracing includes

• Mis-shaped plumes traced in the wrong direction and/or with broad strokes.
  
• Plumes partly in faint ink, partly in darker ink.
  
• Tails of y,q,l,m,g that are missing or traced in dark ink then continue in faded ink.
  
• Redundant traces on figures.
  

But the best evidence is when a barely visible ordinary glyph got retraced as an invalid glyph ("weirdo").  Or when the Retracer mis-interpreted a figure and retraced or added a nonsensical detail.

Maybe working definitions of what a non retraced example

The main clue for a trace being original is that it has faded almost to invisibility.  On the images I posted, some original traces are annotated as such (or as "Rt0").  In the more recent ones, I have been using green labels for those.

Or how you measure untouched image or word?

"Measure", in what sense?

And have you tried these definitions on control manuscripts?... Are there manuscripts in history known to be retraced that you can tie parallels to?

I saw a manuscript that had some of the writing blurred and faded by a spill of some liquid, and then had the affected parts retraced.  

But generally I have not seen examples that could serve as "controls" or comparisons.  Most manuscripts on vellum are written with iron-gall ink, which is fairly resistant to wear and water, and does not fade even after centuries.  That was obviously not the case of the VMS: on the drawings, especially, we can see traces that are now barely visible, and traces that should have been there but are not visible at all now.

This is a very long thread - pages and pages and I did read some of it but I may have missed all of what I am asking for. … so am  I missing something?

As explained above, the evidence I have is thousands of small details.  Any one of them can be explained away in other ways.  But for the ensemble, I think that the MRT is the simplest and most reasonable explanation.

All the best, --stolfi