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 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.
As part of some outreach work, one of us (David), visited the conservation department 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)Â 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.
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.
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.