The scanning process and following reconstruction of the scan data produces a 3-d dataset. Essentially, for every point in space in the object we scan, we get a number that can represent a colour. Using some excellent free software – Drishti - we can turn this data into an explorable computer model. This lets us do fun things like fly though a scroll.

Aside from being a fun video, it is a great way to present the possibilities of our work to archivists, conservators and the general public. You can’t read the ink that is between layers in the video, but you can see hints of its existence – this may provide enough clues to identify the item, or to determine how to further process or conserve the object.

Apocalypto on TV

When the BBC heard about our efforts to Reveal the Unreadable they got in contact. They wanted to know if we had anything they could film and use for television. At the time we were working on the Bressingham Roll (see past posts) and were about to reveal the hidden text inside the roll.

A film crew came along for the day and the video below is the result.

Flying though the Bressingham Roll

To get some idea of the internal structure of the Bressingham Roll, it was instructive to generate a fly-though animation. This peels away the scroll, layer by layer showing what is underneath various layers of parchment and how they are stuck together (if they are).

The two videos below show two different “cuts” though the roll. The first is parallel to the long axis of the roll. The second is across the long axis of the roll – equivalent to making slices of a Swiss roll.

In this video, you can make out some writing – in places the ink was clear enough to give a good X-Ray contrast with minimal post-processing needed to make it visible.

You can see some dark marks on the parchment in this video, some of these are ink, others are some other material in the roll that is also showing up strongly in X-Rays. It’s much harder to recognise the writing in this view, because it isn’t presented to you in the usual format you see it.

Bressingham Roll – Initial Results

Soon after the Bressingham Scroll arrived, we performed a quick test CT scan to determine the settings needed so we could image both the parchment and any ink on it.

A single slice of the scan is shown here, the ink shows up as brighter patches on the whirls of the parchment.

The end-on single slice view of Bressingham roll shows both the parchment and evidence of ink very clearly.

This was imaged at 30kV with a 200um Al filter and post-processing with in-house developed beam hardening correction software.

Introducing the Bressingham Roll

As part of our continuing collaboration with the Norfolk Record Office, we’ve recently taken temporary possession of a parchment roll from a bundle in their archives (Call number PHI468,577X9)

Phi roll 002

The Bressingham Roll as unrolled as possible. The section to the right of the image is stuck together.

Phi 468 001

End view of the parchment roll in rolled up-state

The roll is unfit for production in the archives, with the inner portion becoming stuck together.

The ink used in the writing contains both iron and copper, so should have good contrast in X-Ray imaging.

Making Iron Gall Ink (Ferrogallic Ink)

As part of some outreach work, one of us (David) visited the conservation dept of the

Oak Galls to Ink

Westminster Archives, to assist with making some Iron Gall ink for use in the archives and to take some back to the Apocalypto Project lab for experimentation.

The history of iron gall ink manufacture includes plenty of alchemy, many recipes for ink include (some or all of)  urine, vinegar, blood, resin, wine and spirits. In the modern era we know that the active ingredients and a source of tannins and a source of iron ions.

We decided to standardize upon the following recipe.

Boil 2g of powdered oak galls in 200ml of water for one hour.
While solution is still hot, add 24g of Iron (II) Sulphate.
When all the Iron Sulphate is dissolved, add in 4g Gum Arabic.
Filter the solution and bottle.

Boiling oak galls for ink

Upon adding the Iron (II) Sulphate to the oak gall infusion, a dramatic colour change occurs; the pale orange/brown liquid turns deep blue-black, indicating that the tannins from the oak galls have formed chemical complexes with the iron ions. When all of the iron (II) sulphate dissolves the ink needs filtering to remove insoluble particles.

 

Filtering ink

The whole process took just over three hours, the majority of that time spent filtering the ink, finely powdered oak galls clog filter-papers wonderfully.

Meagen Smith has also written up the ink making adventure.

An Endorsement

This pleasing endorsement of the project arrived from Dr John Alban at the Norfolk Record Office.

Through my colleagues in the Norfolk Record Office’s conservation section, I have been following your project with great interest, and we were pleased to provide you with a ‘non-archival, non contextual off-cut’ on which to experiment. It has been intriguing to see the results of your processes for reading unrolled manuscripts and the way in which they have been improving. The latest example which I have seen has amazing legibility, and I am sure that this process is going to provide archivists and historians with an invaluable means of gaining access to the contents of rolled-up documents which, because of their condition, have hitherto been unreadable.

Yours sincerely,

Dr John Alban

[Posted with kind permission of Dr Alban]

Unrolling the Unrollable

Thanks to the efforts of Meagen Smith at Camberwell, The small scroll of parchment from the Norfolk Archives has been successfully unrolled. We can now compare the X-Ray digital unrolling with the until now hidden text.

Unrolled Norfolk Archives parchment

Digitally extracted text from the XMT scanned parchment scroll

It is clear that the extracted text is from the middle portion of the scroll – the text matches perfectly.

Revealing the Unreadable

New scroll, new challenges. First, we were pretty sure that our scroll is two-sides written,  same as the scrolls we processed before. The further analysis revealed that this parchment is one (OUTSIDE) side written, with lots of confusing bright spots of the metal dust on both sides of the parchment. Also we noticed the inside parchment surface generally is much brighter than the outside surface, with the intensity close to the ink intensity.

Slice from the top of the scroll with a tightly connected metal strip

The next challenge was the metal strip, which has the same intensity as the ink, and very tight connected with the parchment near the top edge of the scroll.  Although we can track the strip and remove it as a separate object in a similar way as we did for the two pages scroll, there are messy areas which impossible to separate without leaving parts of the strip on the parchment.

 

 

 

After the automatic unrolling the result looked promising, but not very readable:

After another week of experiments with the local segmentation, filtering, postprocessing and interpretation, almost everything become readable. The scroll appears to be an old, property related legal document.  As one can see on the original photos , the parchment is the cut fragment,  words are missing from both sides, left and right.