Author: Ryan Winfield

The WOAM coffee break area, site of many useful insights.

Lars Andersen Tries to Help Me Understand Freeze Drying

Lars Andersen has apparently written the most marvelous book on freezer drying, but it is only in Danish. Upon encouragement from a colleague and boldness from a beer on an empty stomach, I walked up to him and told him I had heard of this book, and was wondering if it would be easier for him to publish in English or for me to learn Danish. He laughed, and it was clear he was quite proud of the book and how accessible it was for many audiences because it did not involve lots of mathematical equations. But he is very busy with many projects and the book might not happen in English. He was kind enough to come up to me after my presentation and explain more about freeze drying to me.

Here is what I think I now understand about freeze-drying and PEG: at low temperature, ice forms, and because of the special qualities of water, ice is very pure. PEG molecules cannot be between the crystals of water, and so the PEG forms sheetlike shapes in the voids of the wood (let’s say we are talking about a big PEG molecule, like 3350.) These sheets go in various directions and make a nice supportive framework of struts. Then at low temperature, the ice sublimates directly to gas, which allows us to get around that pesky problem of capillary action. As I understand it, the problem with waterlogged wood collapsing on drying is largely about

1) structure that is missing from deterioration (nicely handled by the PEG you put in) and

2) the violent forces that water exerts upon the weakened wood when it evaporates (“evaporate” as in liquid changing to gas, and that is nicely handled by the solid ice skipping the liquid phase and going right to gas in sublimation.)

So to get rid of the water it needs to be in a freezer. Now, that process goes FASTER in a vacuum freezer dryer, because there is a vacuum and a heating element (it seems freezer drying gets slower as temperatures get colder…I never realized that before.) But the only big advantage of the vacuum freezer dryer is that it is faster than a non-vacuum freezer. Roughly twice as fast for small things like my basketry. Maybe up to 10X faster for big things like ship timbers. But beware, for lightweight little things sometimes the vacuum freezer dryer can toss things around in the chamber if you’re not careful. Oooops! And then there is that whole pesky eutectic point thing. The literature says you should avoid the PEG eutectic point of 55%. If I got this right, at a concentration of around 55%, the thermodynamics of the water and PEG system are such that water comes to a kind of happy balanced place in terms of energy and no more water wants to come off the PEG and make ice. So there is PEG with liquid water on its surface, not freezing into ice, and instead of making the nice sheetlike structures, it makes these massive weird gobs. Lars Andersen’s book has some great SEM images of these two very different looking PEG formations (the nice struts and the wired gobs at the eutectic) and you can see where the ice that does form in those gobs would have a hard time sublimating. The vapor would have a very crooked path to follow in order to get out.

Now I missed a bit of a point here, I think it had something to do with solving that by either making the temperature very very cold, or by keeping it in the vacuum freeze drier for a really really long time, so you are missing out on the benefit of the vacuum freeze dryer. And it is NOT AN ISSUE if you are using a non-vacuum freeze dryer. I also realize that my nice IPM freezer going down to -35C is not an advantage for me. The sublimation would actually happen faster if my freezer were not so cold. I could make this go faster by using a fan and some silica gel. But for me at this point, waiting a few weeks for a basket to dry is no big deal.

For a review of all the papers and posters at the 2010 WOAM conference, please see my weblog at http://ellencarrlee.wordpress.comhttp://ellencarrlee.wordpress.com.

WOAM visits the conservation lab for the Queen Anne’s Revenge shipwreck.

WOAM ZOO: THE HYBRID ANIMALS

Let me tell you about the exotic creatures that I am most intrigued with after this conference. Tara Grant: working on treatment of waterlogged organics like fur, baskets, skin, feathers…she has archaeological experience in the field and that cautious AIC standards and ethics mindset I relate to. Plus, she’s been fighting the good fight for some time and has a database in her head of things that have worked and have not worked, and she’s been on the front lines over there at CCI for a long time. Cliff Cook: Also dealing with the stuff that is similar to my stuff in Alaska, with a similar cautious treatment philosophy and long CCI background that Tara has. Another observation: Cliff Cook is a good guy. He was very helpful in answering my many questions on many topics when I cornered him at the conference, and it seems like he has a long, long career of being very helpful as well as stepping up to the plate and doing behind-the-scenes work of the kind you don’t often get credit for, but I find really helpful in what I’m doing. There are not a lot of people who seem to be this hybrid of conservator-doing-treatments-according-to-AIC-standards and ethics who can also really grapple with the science and has a foot in today’s world of archaeology. And I guess I mean archaeology in the United States, and marine archaeology in particular. That’s the kind of hybrid who is most interesting to me, and who sort of speaks my language…Ian Godfrey: From what I can tell, he is more of a scientist I think, really, but the practical treatment stuff is also in his realm and he’s been at this a long long time. His talk was the last of the conference and pretty masterful. I am still trying to figure out all the factors that go into grappling with the right treatments to do and how to assess them in a holistic big picture way that comes out with a concrete result we can take to the bench but that is still scientifically backed up, and to see this man just put out a talk like that with such flare (and then wrap up with the most amazing images of penguins you ever saw…did you know he’s done a ton of work in Antarctica? Google him) well, it made me feel like I was seeing an orchestra conductor or something. He is also looking at non-wood organics, and WOAM is pretty dominated with the wood people who are finding solutions for shipwrecks and the like. If I understand correctly, these big shipwreck projects bring in the funding so you can attract scientists to help with the research. But what about ivory? Baleen? Skin? Hair? Bone? Fur? Feather? Baskets? Textiles? There is just not the same volume of research being done on that stuff, and it seems like Ian Godfrey has a special interest in that. Me too, and I think knowing more about that stuff archeologically will help us better preserve the stuff that is NOT archaeological but ethnographic, and by that I mean old stuff made from plants and animals that has not been dug out of the ground. Susanne Grieve: She’s in this very tiny category of conservators treating objects in marine archaeology in the US who have the kind of training I have (by this I mean graduate degree in conservation from a program that is tight with AIC-type philosophies: namely the NYU, Buffalo, Delaware, Queens, London and now Getty programs). In the United States, a huge percentage of our maritime heritage is being conserved/restored/preserved by people who are mainly trained by archaeologists and don’t follow the AIC standards and ethics. Granted, maritime stuff is really challenging and application of the AIC standards and ethics is complicated in these cases. But there are two parallel universes of practice going on in the United States, from what I can tell, and only a handful of other people have a foot in both worlds like this. I’m especially excited about the Susanne factor because she is in a teaching position that has potential for really interesting impact and bringing those worlds together. Quite a burden, but full of promise as well. Go Susanne! Gary McGowan Now there’s a sweet guy. You’re feeling a little shy at a conference with all these big names? Cling to Gary, he was so nice to me! He’s in private practice in the New York area and has seen lots and lots of stuff, plus kept his ear to the ground and heard about a lot of stuff good and bad. Katherine Singley is another one of those. Wish there could be an update to her book. It is still one of the basics on the bookshelf for this stuff. And Howard Wellman! One of those folks who stays very active in AIC but also attends archaeological conferences of all sorts. He had some really practical advice for me about connecting with archaeologists in Alaska at their next conference. He has also been very helpful when I have emailed questions to him, and this year he wrote me a recommendation so I could get grant funding to come to WOAM.

So these folks are primarily English speakers, and certainly there is a wealth of info in the folks for whom English is not the first language, but being new to this conference I was too shy to get face time with everyone. With a finite amount of time to make connections, I started by limiting the variables I needed to process. Language was one, but also my own lack of knowledge about which aspects of the ethics puzzle are the same and which are different in various parts of the world. I didn’t really get a chance to tap into the UK folks very much, although that’s gotta happen because they really understand the contract archaeology thing that is so intense over here in the US, too. Cultural Resource Management driven stuff. I know I am going to kick myself for not putting more effort into cornering Jim Spriggs in particular. I hope I get another chance in 2013, I have a feeling he is a vast reservoir of really important info. Please note, these are just my own observations about the way the world works and opinions about individual personalities. Perfect for the blog format, but keep in perspective that this is just how I am interpreting the limited info I have absorbed. There is so much more to know!!

For a review of all the papers and posters at the 2010 WOAM conference, please see my weblog at http://ellencarrlee.wordpress.comhttp://ellencarrlee.wordpress.com.

Not a picture of the business meeting, just lunch! Around the table from lower left: Dana Senge, Khoi Tran, Gille Chaumat, Paolo Dionisi Vici and Susanne Grieve.

WOAM business meeting

This conference in Greenville had some 85 delegates from at least 15 countries, 43 papers (12 of them peer reviewed) and 13 posters. The peer review aspect is interesting. In academia, there is the great need to “publish or perish” but for many people, conference proceedings do not count toward their total of publications. Later, over beers, I had the chance to discuss this with Dutch environmental biologist Michel Vorenhout who explained to me that you get a certain number of points for getting your paper into a journal, or a book by a known publisher that counts (Archetype is one of those publishers, by the way.) And whether or not something counts depends on how often it is cited elsewhere. Science and Nature are the ones that are cited most, so they are worth the most if you get an article in them. Apparently, there is one big company that keeps track of all that and assigns the number value. As far as the WOAM papers are concerned, scientists tend not to take things seriously if they are not peer reviewed, and yet WOAM being a conference proceeding, it doesn’t really count for most folks. So scientists are likely to save their best research for publication somewhere that “counts.” For me, I liked the peer review because I felt like it was double-checking my work for really egregious mistakes before I had to get up in front of people. But with WOAM, there is also the Q&A period of critique and feedback during the sessions that gets published after each article, and this is a sort of peer review. As Cliff Cook said, “Everybody gets to kick the cat.” Having special issues of certain journals could make that work. Conservation and Management of Archaeological Sites is one such journal. But certainly we could not fit in all our papers in one issue, right? If you split it up, this info might be harder to find? People might miss out? As for Archetype, you have to pay them to publish the book, and then buy the book from Archetype. So there is an economic consideration at play there. Some journals, like SHA, can take several years for the findings to be published. The system WOAM has now puts things out faster. Here’s another issue: some people cannot get funding to come to a conference if it is not peer reviewed. One big issue that the group decided to tackle was which back issues of the WOAM conference are still available and who has them. Some are very difficult to find. We might even need volunteers to copy old ones. What if we printed fewer copies, and then put them up on the web for free? What about being on CD? Some folks are opposed to them being on the web for issues like copyright and control. In the world of science, there is a lot of pressure to make info free after three years or less. Folks discuss the idea of trying to put WOAM into JSTOR, where people could by articles one at a time. Studies in Conservation and JAIC are available there. Copyright for WOAM remains with the author, so people could email the author for a copy? Of course, authors don’t live forever. If we put titles of all the articles on the web, Google could find it more easily. All the abstracts are already in BCIN and ATAA.

Then the group discussed issues we plan to think about for the next three years and who would be the point person (mostly a formality for the ICOM-CC) These were:

InSitu Preservation (Michel Vorenhaut)

New Materials for Organic Conservation (Hartmut Kutzke)

Reconservation of Alum in wood etc (Susan Braovac)

Acids/sulfur/iron in organics (Vicki Richards)

PreConservation (post recovery) Storage (Sarah Watkins Kenney)

Materials Characterization, Standardized Assessments of Condition, and Assessments of Degree of Deterioration (Ian Godfrey, Katarini Malea, and David Gregory)

Post Conservation Display and Storage (Emily Williams)

Review of the Wood and Methods from 1987 Study (Elizabeth Peacock)

Challenges in Conservation (kristiane Straetkvern

Looks like there is solid support for the idea of Tara Grant becoming the next coordinator, with Emma Hocker and Khoi Tran being co-coordinators and several other folks being willing to pitch in and help. That will decided at the ICOM meeting in Portugal in 2010. Three places were suggested for a 2013 meeting: Australia, Istanbul, or Germany. The Australians were concerned about getting enough attendance in Australia, it’s such a long way to go and not much of a local audience there. Only about 20% of the room thought they’d be able to go there. The 1987 WOAM in Freemantle (which was a combo with the metals group) was not very well attended, and the proceedings were slim. Going to see the flying ship in Xanten was pretty exciting, but I think things are looking like Istanbul in 2013, and not just because Ufak promised us a belly dancer. But he did promise!

For a review of all the papers and posters at the 2010 WOAM conference, please see my weblog at http://ellencarrlee.wordpress.com.

http://ellencarrlee.wordpress.com

Paolo Dionisi Vici squeezes into Susanne Grieve’s car to go to lunch at the WOAM conference

Imagine a field where the artifacts to be treated are ridiculously delicate and complex, as well as deteriorated. Imagine you have to make weighty decisions in a hurry, because the artifacts are going to get irreversibly much worse very fast if you don’t. Imagine you don’t have much time to make these decisions. Imagine the artifacts are often wonderful and amazing, with high exhibition and research potential. Ready, set GO! And don’t mess up! This is what we’re talking about with waterlogged material that was once plant or animal in origin. Since 1981, there’s been an ICOM-CC working group for Wet Organic Archaeological Materials. It meets once every three years and puts out proceedings. There are a few really special things about this group, and one of them is their reputation. Highly professional, very international, unusually welcoming and open-minded. And in a way, they have to be. Many of these treatments have gone wrong in the past. There is a lot of material for which there is no fully satisfactory treatment. Perhaps to a greater degree than many other areas of conservation, this group needs to learn from mistakes and dead ends. So it must welcome them. The call for abstracts well in advance means that you write up an abstract for what you hope will be your happy outcome, and then you must come and tell folks why if it didn’t turn out that way. And they will cheerfully say, “Thank you! Nice try! Most interesting! What can we learn from this if we put our heads together?” Maybe someone might pull you aside over a beer and gently suggest something you had not thought of, but they did not want to seem harsh in front of the group. Honestly, there are not that many people worldwide working on this kind of material, so we cannot afford to be isolationist. An innovative feather keratin treatment was been the buzz for a while, and someone came from Japan to describe it. Someone else from Denmark reported results from separate analysis in the next presentation, and the conclusion was that the feather keratin treatment is probably not the next big thing. But everyone wanted to hear it and glean what kinds of clues and insight there might be in the study of the material. Later, people were saying, “Isn’t there something going on in Italy right now with starch? What are they up to? What about the work in Mainz?” Those folks may or may not have success with their experiments, but they can rest assured they would be most welcome at WOAM. Some nice things about the structure: the conference is all one big session, not concurrent sessions. The poster folks have to get up and give a little verbal 5 minute summary. There is lots of group discussion. And maybe the best thing they do, is they write up all that verbal discussion in the proceedings!! As one delegate (attendees are called delegates) said to me, “When I read a WOAM article, first I read the abstract, then I read the comments at the end, and finally I read the article.” I think those comments and discussions published at the end really give the flavor of WOAM. Very intellectually curious and not interested in passing a judgment about good or bad, but rather a search for the useful.

Today is Sunday May 30th. Last night I was in tears because I missed my connection home and now I am stuck with 6 ½ extra hours of travel. But it is a blessing in disguise. This is the first time I have really had some clearheaded, well-rested, caffeinated time to reflect and process on the conference. During the conference, I was talking to people or attending talks from breakfast at 7am, clear through till my head hit the pillow, exhausted, at 10pm. In talking to people I was processing the information, but also taking in new information the whole time. Being there was exhilarating, but while I was in the middle of it there was little time for processing what I was learning and synthesizing new ideas. For a review of all the papers and posters at the 2010 WOAM conference, please see my weblog at Texthttp://ellencarrlee.wordpress.com.