There's been comments about the lightfastness test setup which, in most cases for hobby and smallscale professional dyers, consists of picking a south-facing window and sticking stuff in there for a given amount of time... which is very obviously not a scientific way for evaluating lightfastness.

First of all, though - let's take a closer look at the things that happen when light hits that textile. I've brushed up my knowledge a little bit, but please note that I'm not an expert, and I'm going to put what happens, as I understood it, into very simple terms. If you want the nitty gritty details, you can check out "Chemical Principles of Textile Conservation" by Agnes Timar-Balazsy and Dinah Eastop (published 1998), where pages 88-92 and 225-232 will bring you many insights.
Basically, what happens is that the light hitting the fabric inserts energy, and this energy can cause chemical reactions on molecular levels. One of these processes is photolysis, where bonds in the dye molecules are destroyed, leading to a different chemical structre and thus a change or loss of colour.

The second process, and even more important than straight photolysis, is photo-oxidation. When this happens, a carbonyl group in the dye molecule changes to  carboxyl group, leading to a shortening of the dye molecule and thus a colour fade. This process is usually slower if humidity is very low, and can also be slowed down by an atmosphere with less oxygen (though some colours may fade faster in a vacuum - so you can't be sure if that is good or not). Metals including iron and copper, as well as their compounds, can aid photo-oxydation. Even nastier about this process is that it can result in active radicals such as hydrogen peroxide, which is a bleaching agent, speeding up the fading of the textile.

Different dye molecules are more or less prone to these reactions to light, which explains the varying lightfastness levels of dyes. Both UV light and visible light provide energy for these reactions, but the wavelengths do make a difference.

So... now that we all know, more or less precisely, what happens when the dyes fade, we can get back to testing.

Well, it's a bit to wait until the prime season for lightfastness tests (three months in a south-facing window in summer, I've been told, would be the perfect thing), but the fabrics from the Dyeing Experiment are all set and prepped... and I might hang them into a window a bit earlier than full summer:



I'm really, really curious to see how well these will hold up, and if there is any difference between the metals that have not made very obvious changes to the colour, and the reference.

So. Summer. I'm ready for you.

One of the things about archaeological experiments is that they always take longer than expected... and then, in the aftermath, there's... the aftermath.

Which, in the case of the Pompeii Dyeing Experiment, involves making reference cards for the different dyeing results. Which means labeling sheets of cardboard, punching holes next to the labels, and then winding off tiny skeins of yarn which are in turn pulled through these holes and fastened.

If you have never done something of the sort, let me tell you: it takes a ridiculous amount of time, and it is stunningly boring work, and I can totally, utterly understand if a dyer does not do yarn colour reference cards (which are only an indication of what colours are possible anyways) and even better why they are not handed out to customers.

[caption id="attachment_4258" align="alignnone" width="640"] Work in progress - I'm less than halfway through here. Altogether, it's four sets of three cards with five skeins each, so it's sixty samples to wind and attach. Can you feel the boredom oozing through the picture?


Now, though, it's finally done, and I can send off the cards to their respective owners (among them the Lab for Experimental Archaeology, for their archive of experiments done at their place). And then, some samples will go into a different lab for testing - so there's a post office run in my near future, which will be followed by a deep, heart-felt sigh of having finally finished that part of the Textile Forum Aftermath!

A colleague of mine is doing PhD research about best practices in experimental archaeology and is looking for people belonging to a research or academic institution or carrying out independent activities.

So if you are a demonstrator, crafter, re-enactor, or professional who works with or in museums or other spaces, you could do my colleague a favour ahd help with her research by filling out the questionnaire here.

I'm curious to see what she will find out - we've had a long and spirited discussion a few years ago about the problems of experimental archaeology in open air museums, and the possibility or impossibility to run experiments involving the public. (I'm still convinced that an archaeological experiment, in about 99% of the cases, is not something that you can open up to the public and still run successfully.)

Did I say back to the usual stuff yesterday? Well, this year is starting off with exciting things only; for one thing, getting the Bernuthsfeld stuff to a close. (There's just a few more patches to decide upon and to sew in, and the shirt to make. I've already cut most of it, and the rest will be done once I get confirmation on the measurements so it will actually fit the figurine. Nothing worse than sewing something and then finding out it won't go onto the body it is supposed to dress!)

But wait, there's more!

When I was at NESAT last year, Eva Andersson Strand gave a presentation about one of the current projects at the CTR, called "Capturing our intangible past". You can read a bit of an introduction on the CTR website.

One of the aims is to get a better idea of craft knowledge and how to capture it. If you've ever tried to learn a craft skill from a description in a book, you will know that this can be rather difficult - and the motion capture might be helpful in isolating relevant motions without having too much data. If this works, it might also be a good method to record practical knowledge. There's still more, though - plans are to combine the motion capture with an EEG to get an idea of brain activity while doing the craft.

The research group is currently focusing on spinning as a craft, and you can imagine my delight on being asked if I'd like to participate in their study. So I'll be travelling to Lund later this month, to get lots of recording bitsies stuck onto me and to do some spinning. I'm beyond excited, and still can't believe something this cool is coming my way!

 

Here's a stack of things you might enjoy... first of all, the children's quiz show that I was filmed for in January is online for four more days, and you can watch the episode here. (It's the second question in.)

Here's an article about the hatpin in the early 20th century and its use for self-defense.

Looking for something less martial? Here's a 14th century recipe for doughnuts, courtesy of the British Library.

If you are interested in studying Experimental Archaeology, the UCD is offering a new course for a MSc in Experimental Archaeology and Material Culture. Application deadline is on June 2, so if that sounds interesting to you, you will need to be quick.

Speaking of programmes, the Nobilitas Akademie this year will be 10-12 November on Burg Hessenstein. As usual, there's a variety of different topics, all sounding quite interesting! Their programme is online, and you can register for it; if you do it soon, you'll get a bit of an early bird discount, too.

Finally, here is a blog article about a spinning technique with hand spindles that I have on my list of "things to try and figure out how to do" - rotating the spindle in the hand, but not with the hand and finger position similar to short suspended spinning, but more or less horizontally. I've seen this a good while ago for the first time and have since dabbled some with the motion (which is totally intriguing), but as I said, it's still on the list.

Hope you enjoy one or more of those!

Time for a post about interesting things, some of which you can participate in!

If you are in the Southampton area, there's a project about dexterity in flintknapping:With motion capture. How cool is that!

If you're more on the other side of the globe, there's the meeting of the Society for the History of Technology October 26-29, where there's a session about textiles and early industrialisation in planning. You can read more about the Society and their conference here.

There's also a conference about "Embellished Fabrics: Conserving Surface Manipulation & Decoration." It is the 11th North American Textile Conservation Conference, taking place in Mexico City, Mexico, November 6-11, 2017. The website is www.natcconference.com, and it will provide more information in case you're interested.

And another conference, this time in Poland, in June: Dynamics and Organisation of Textile Production in past societies in Europe and the Mediterranean. International Conference, Łódź, 21-22 June, 2017. The preliminary programme looks really nice and interesting!

For those of you who understand German (or for the adventurous of you who don't), there's a TV show where one guy participates in a club for one day, looking at the stuff people do in their spare time... and one of the clubs is a Living History group. You can watch the half-hour show here.

Some more interesting things - Jim Hines has done a survey about novelist's incomes. So if you've ever wondered whether writing a novel will make you rich, you might want to read his long, really interesting multi-part blogpost, starting with part 1 right here.

In 2011, a tunic was discovered in a Norwegian Glacier, and it has since been reconstructed. You can read a bit about the reconstruction and watch a video here. (I'm not totally happy with the spinning part of the video, as you might guess when watching it...)

And that's it for today. Hope you find something you enjoy among these!