VMs: Inks and retouching

[Jorge Stolfi <stolfi@xxxxxxxxxxxxx>]

  > [Knox:] About converting to jpg, is there any advantage to having
  > a jpg the size of a sid rather than the sid, itself?

Only that JPEGs are understood by most browsers, while SIDs are not.

  > [Nick:] For me, the initial question is whether we can demonstrate
  > whether any of the labels the Heavy Painter painted over had
  > already been retouched by the Retoucher... something to think
  > about!
  
Yes, that is a good question. We *may* be able to answer it through
color separation on the current SID images.

It would be better if we had the TIFFs. The SID format (like the JPEG)
adds small-scale noise that breaks the color algebra, so we have to
work on smoothed (=lower resolution) versions of the images. Besides
the TIFFs presumably include a greyscale calibration card. I am
seriously tempted to fork US$ 30 for a couple of TIFFs, say of f1r...

  > [Jeff:] What if the 'retoucher' could read the manuscript? Then it
  > would not necessarily be the faintest characters that would need
  > retouching but the ones in the lines with the most interesting
  > content. This would give emphasis to the sections of more worth.

One cannot be sure, of course, but the retouching seems to be too
random to have been made for emphasis: a letter here, half a word
there...  And it does seem to be focused on the places where the
un-retouched text is faintest.
  
  > [Glen:] Now you go and start attacking the text - something I
  > personally hold as gospel.

Fortunately it seems that the Retoucher (unlike the Painter(s)) also
had the same veneration for the text, and made an effort to preserve
all details.

For instance, there is lots of variation on the plume on EVA "sh" --
long or short, curled back or almost straight, etc. From what I read
here, it seems that most of us think that those traits are
meaningless, just normal variation seen in anyone's handwriting. Yet
the Retoucher apparently tried to preserve those details, by carefully
retracing the old plume -- instead of drawing a new one in his own
style.

I believe that he *did* introduce some noise, by changing some "a"s
into "o"s, "r"s into "s"s, etc.  I owe the list a more detailed
discussion, with examples, so that each one can decide for himself.

Yet I think that, on the whole, we must be grateful to the Retoucher.
Without his work, many parts of the text would have been unreadable
by now. Morever he and the Painter made the manuscript more valuable,
and probably saved it from being tossed away (or used for tinder, 
like Dee's Angel Diaries?).
  
  > [Glen:] We can split the colors now, so we've all become some sort
  > of epigraphic or forensic specialist? NOT! Be very careful on how
  > you interpret the data from your new-found toy.

You don't need to tell me that, I am aware of all the difficulties
you mentioned (and of several more that you didn't).

However I do have some knowledge of the matter. My "real life" work is
mostly about computer graphics and image processing, so I am supposed
to know about colors and how they arise. Moreover my mother was an
artist, and my father had a car body & paint shop; so I grew up
playing with pens, brushes, paints, and inks of all kinds...

  > Tell me, was the VMS written with a stylus, or maybe a quill, or
  > maybe something different?
  
With a pen, definitely -- you can see the strokes splitting into two
tracks when the pen is running out of ink and/or being pressed harder.

Assuming the writer was an European, it was probably a quill pen. But
I suppose that a reed pen (as used by Muslim and Jewish scribes) would
also produce that effect.

I did not manage to make my own quill pen yet; but I made a couple of
"reed" pens from bamboo twigs, according to recipes found on the web.
They work but are rather fragile; I would not dare to press them so
hard as to make the widely split strokes seen in the VMS. That would
not be a problem for a quill pen, obviously.

  > What are the writing characteristics of each on vellum (our
  > medium), and how many VMS characters can each write before it
  > becomes necessary to re-ink?
  
With the proper ink and pen, I would say "a few words". But it 
is quite possible that the VMS author's pen was not up to the
standards of his time.

Refilling used to be the explanation for the variations we have long
seen in ink density, and indeed it is hard to disprove that
explanation. We suspected retouching for a couple of years, since
Beinecke posted the old color negatives; but until the new hi-res
scans there was no good evidence of it.

Besides a few places where the old strokes are clearly visible (like
that one on f1r), there are many places where a "dark" letter, or only
part of it, occurs alone in the middle of an otherwise "light" word.
If refilling was the explanation, we would expect to see a "sawtooth"
effect -- the ink gets suddently dark, then gradually light.

Moreover, the color analysis results are quite consistent with what
theory predicts for two inks of different color; and very difficult to
mesh with the hypothesis of one ink applied in various thicknesses.
(One would have to assume a highly "kinked" relationship between light
intensity and pixel values, which the Beinecke scanner was designed to
avoid and which would surely produce other artifacts that we don't
see.)

  > How often did each [kind of pen] need to be sharpened?
  
I don't know, but my guess is at least several lines, possibly a page
or more. How much can a quill pen wear down when dragged over soft
leather? The quill material is flexible but fairly tough...

  > Is the vellum of the same surface and porosity throughout?
  
Certainly not. In the new images, the lighting was from an angle, 
so the vellum relief and texture are fairly visible. 

One can see, for example, places where the writing has clearly faded
more than elsewere, because a crease in the vellum made that part of
the page stand out and hence be more exposed to rubbing.
  
  > When you can take a page apart and demonstrate each time the
  > author re-inked, you can continue to talk about "retouching",
  > though I'm certain this criticism won't limit your confidence
  > level.

Well, the images are there, the arguments have been said -- each
one of us can draw his own conclusions. 

  > Let's talk about that ink for a bit - is it consistent throughout? 
  
As I mentioned recently, the "old" ink in some Zodiac pages seems 
quite different from the "old" ink in the herbal and other sections;
and both seem different from the "new" ink.  

It is possible that the "old zodiac ink" is just a stain left by the
ink's binding medium (e.g. oil) after the pigment proper flaked off.
However I do not see that happening in other sections. Elsewhere, the
old ink seems to fade away gradually, without leaving any stain
behind.

  > When the ink was made (presumably by hand and not by Parker's),
  > did the author always maintain a 50 micron particle size for each
  > component, or did his mixtures vary as much as his writing
  > instrument?
  
The nature of the VMS inks are still quite puzzling. My guess (just a
guess) is that the pigment in the old ink, at least in the herbal
section, was ocher -- a common clayey mineral pigment used for paints
and such, which seems to have just the right color.

AFAIK, that recipe would be very unusual for a writing ink, but could
explain why it faded so easily and washed off with water. (Standard
iron-gall ink, from what I have read, was popular precisely because it
was waterproof and rub-proof when applied on vellum.)

Ocher would be bought by the pound, already in powder form; so it is
quite possible that the pigment grain size -- at least -- is uniform
throughout the book

Judging frm its color, the "new ink" pigment could be a mixture of the
"old ink" one and lampblack. If true, that would be an argument for
the Retoucher being the Author himself.  But that too is only a 
guess (not worth a pizza yet!)
  
  > Some of the paint particles at least can be seen under very low
  > magnification.
  
The color paints certainly are highly varied, The handwriting expert
already observed it in the 40's. The way they were applied varied a
lot too.

Many blues and greens, for instance, seem to have been painted by
someone who was too lazy to clean his brush before switching between
them. On other pages, the blue paint seems to have been applied with a
stick, not with a brush.

  > Consider, when you sharpen a quill by hand, does it write exactly
  > the same afterward? [... long list ...]?

Again, I am well aware of all those issues, and I do see many of those
effects in the VMS. But I also see things that I can only explain as
retouching -- lots of it.

  > BTW Jorge, where exactly do I have to travel to pick up that
  > Pizza, or is local delivery a viable option? :-)

My son is now living in Boston, I suppose he could act as my
representative -- he could call a restaurant near you and have it
delivered. Or vice versa... 8-)

All the best,

--stolfi

______________________________________________________________________
To unsubscribe, send mail to majordomo@xxxxxxxxxxx with a body saying:
unsubscribe vms-list