Event Logs

Collapse

• Hack Chat Transcript, Page 1

  Tom Nardi • 01/24/2024 at 21:34 • 0 comments

  Dan Maloney  3:00 PM OK, let's get things going. I'm Dan, I'll be moderating today along with Dusan as we welcome Ahron Wayne to the Hack Chat. Ahron has done some cool work with X-rays and CT to visualize ink on carbonized papyrus scrolls for the Vesuvius Challenge:

  Dan Maloney  3:00 PM https://hackaday.com/2023/11/02/2000-year-old-charred-manuscripts-reveal-their-secrets/

  Dusan Petrovic  3:00 PM Hello and welcome everyone!

  Dan Maloney  3:01 PM Welcome to the Hack Chat Ahron. Can you kick things off with a little about your background and how you got into the challenge?

  Ahron Wayne  3:01 PM @anfractuosity I'm a bit of a broken record in The Challenge talking about the wavelength you've mentioned --- Thz are PERFECT for ink-paper discrimination and that kind of thing because they can make it through the material while being influenced by the chemistry of organics (i.e contrast between paper and ink). The only annoying thing is it's really hard to make and detect the frequency (thz gap)

  Ahron Wayne  3:01 PM Hi Dan! Thanks for inviting me

  anfractuosity  3:02 PM ahh, thanks a lot

  Ahron Wayne  3:03 PM So my background is a bit varied. I'm mostly biologist by training but I do industrial X-Ray CT as my main job. While there I was curious about whether you could look inside a pack of pokemon cards (coming full circle to my teaser a couple days ago), and this led me to the herculaneum scrolls --- it's a very similar problem. I reached out to some of the original authors, especially Stephen Parsons and developed a good relationship. Later I saw the vesuvius challenge on the news, I mentioned it to him, and he told me to join

  hannes.hoffmann  3:04 PM Thz was a thing at least since 2016. I had been sending this paper to people involved at the time: https://www.nature.com/articles/ncomms12665

  hannes.hoffmann  3:04 PM nothing quite came of it

  hannes.hoffmann  3:05 PM i understand the depth discrimination hasnt gotten better

  Ahron Wayne  3:05 PM @hannes.hoffmann I think it's more of an applications thing than anything --- CT is so well researched and developed that it's relatively easy to find a machine to throw your scroll in (though the scrolls were scanned at the Diamond light source). Everything THZ is basically custom.

  wilkij1  3:06 PM What accelerating voltage did you use? And what sort of detector?

  CLamb  3:07 PM There is a similar problem with imaging motion picture film rolls which are too badly deteriorated to unroll. I imagine a higher resolution than for imaging scrolls would be required. The silver in B&W film would be more opaque than the film base but discrimination of the dyes in color film would be difficult I am assuming.

  anfractuosity  3:08 PM isn't colour film, done with layers per colour, or am i imagining that

  CLamb  3:08 PM That's how colour film is done.

  Ahron Wayne  3:09 PM So the Vesuvius challenge has its own dataset --- the real scrolls, from the volcanoes, were scanned at the Diamond light source, a synchotron. Basically a super advanced lightbulb for x-rays. You can get a monochromatic (single wavelength) that way --- I believe the first scroll was scanned at 58 khz, with a cool detector as well. In my lab experiments, next to me I have a GE Explore Locus SP with a Kevex PXS-925 x-ray source (very old and mostly broken) that I mostly run at 60kv. The detector is also pretty weird because back then they had to couple the scintillator to the detector with a bundle of optical fibers.

  CLamb  3:09 PM A minimum of four layers but I know of films with up to seven.

  Ahron Wayne  3:10 PM

  Ahron Wayne  3:10 PM The machine I have next to me --- from ebay

  anfractuosity  3:10 PM Is 60kV fixed, or can you lower that?...

  Read more »

• Hack Chat Transcript, Page 2

  Tom Nardi • 01/24/2024 at 21:33 • 0 comments

  Thomas Shaddack  3:53 PM Could polaroid-class instant camera film work for xrays (or autoradiography)?

  bruniss  3:54 PM diagnosis: crack

  Ahron Wayne  3:54 PM Lol. Hey Bruniss

  Dan Maloney  3:54 PM They actually use both Ilford 4x5 film and Instax instant film in the project. Both work pretty well

  CLamb  3:54 PM @Dan Mahoney Photographic film? Are you imaging the film directly or is there a luminescent intermediary.

  CLamb  3:56 PM @Dan Maloney I mean "exposing" not "imaging".

  Dan Maloney  3:57 PM Not me, writing it up as a daily for the blog. Couple of guys presented the work at Schmoocon last week or so. Pretty sure they used some kind of intensifying screen, I'll have to check

  Dan Maloney  3:57 PM Nope, I take that back -- no screens, direct exposure. Long exposure times, like 120-180 seconds

  Ahron Wayne  3:58 PM Sheesh.

  Dan Maloney  3:58 PM Don't want to derail the chat, though -- just a side note. Article will be out in the next day or two

  anfractuosity  3:58 PM wow, didn't know that'd work

  Ahron Wayne  3:58 PM

  Ahron Wayne  3:58 PM Any questions on the act of making pretend scrolls?

  anfractuosity  3:58 PM haha cool, what material is that

  Dan Maloney  3:59 PM Oh yeah, meant to ask about your roasted scrolls. Where does one get papyrus these days?

  Will Fitzgerald  3:59 PM What kind of ink did you use?

  hannes.hoffmann  3:59 PM Things to scan: spring onions. Preferably dried/carbonized.

  Ahron Wayne  3:59 PM

  Thomas Shaddack  3:59 PM Pieces of charcoal. Also internal structure remaining from the wood.

  Ahron Wayne  4:00 PM I tried to get papyrus from a few different sources --- I mainly found small postcard sized sheets, thicker than the ancient stuff, and more realistic swathes that came directly from egypt (it literally had nile river in the return address). Amazon and Ebay were the actual sellers

  Dan Maloney  4:01 PM TIL that Egypt still has a papyrus industry...

  Ahron Wayne  4:01 PM @Will Fitzgerald , I got ink from standard fountain pens and also different India inks, which do have modern binders but are still mostly just carbon... hopefully... And I also tried to mix up my own dense inks to act as reference points, which is surprisingly harder than I thought.

  Ahron Wayne  4:02 PM

  CLamb  4:02 PM Was it the carbon in the ink the component which was most radio opaque?

  Thomas Shaddack  4:02 PM barium sulfate wouldn't work?

  Ahron Wayne  4:02 PM I used a 3D printer holding a pen to try and standardize the writing process somewhat.

  Thomas Shaddack  4:02 PM it's available as pigment grade, I think.

  Ahron Wayne  4:03 PM @thomas, if I could find it as a wax stick or something, sure. I did try barium sulfate, but it's hard to write with --- insoluble.

  CLamb  4:03 PM Did you ever try to duplicate the ink on the real scrolls?

  Dan Maloney  4:03 PM Is the chemical composition of Roman ink known? There has to be some kind of record -- seems like they wrote down everything

  Thomas Shaddack  4:04 PM Pigments are insoluble (if soluble it's a dye, I think). Carbon itself. It's then about the size/shape of particles, and keeping them dispersed.

  anfractuosity  4:04 PM Have you heard of sumi ink, that uses soot too

  Ahron Wayne  4:04 PM The basic recipe for carbon ink is --- burn some fat underneath a tarp. Scrape the black stuff that forms. Profit. (in other words, india ink)

  SimonAllen  4:06 PM I wonder if carbon or charcoal ground with a pestle and mortar would work

  CLamb  4:07 PM In modern times lampblack is the carbon that is...

  Read more »

View all 2 event logs