Hi all! I’m Rebecca Jacobs, the new Paper Conservation Technician. I have worked in the lab for about a month and have spent my time learning new skills like mending and encapsulation, as well as creating custom boxes and enclosures. While I’m new to this position, I’m not a stranger to the Indiana University community. You may have seen me around a few years ago at the Kinsey Institute where I helped care for and digitize works in the art collection, or more recently over at Kelley School of Business where I worked as the Selection Archivist.
In addition to working with collections at IU, I’ve also worked for the Indiana Historical Society as a Metadata Cataloging Assistant and have held internships and worked on collaborative projects with many of the museums in the Indianapolis area. I’ve enjoyed working at the Preservation Lab so far because it has given me a chance to use tools that are new to me and to improve my skills on detailed work like mending, and focus on learning more about paper as a material type.
When I’m not working at the Preservation Lab, one of my favorite things to do is experience collections at other cultural institutions as a visitor. Getting to interact with objects in this way reminds me of why I was originally drawn to Collections Care and Preservation and prompts me to reflect on how my work connects to how visitors create their own experiences with collections. I’m excited to carry this intention into 2019 at the Preservation Lab, and hope to share more about projects I’m working on in the coming months.
Things have been relatively calm in our corner of the blogosphere for several months, so I thought I’d add a post about a treatment I’ve been working on in the Paper Lab. We received five leaves of correspondence from the US History manuscript collection at Lilly Library. The small collection of letters are written in German by Philip Boehm, a Union soldier, to his sister during the Civil War. All have been laminated in a manner that was new to me: it appears a well-meaning, but ultimately misguided person placed each leaf in a plastic3-ring binder pocket protector and then used a domestic iron to melt and seal it all together. The film is perhaps polypropylene or polyvinyl chloride (I didn’t do the testing to confirm).
Most laminations involve a commercial product: either a heat-set or pressure-sensitive adhesive backed film is applied to both sides of a document. Over time, the films can oxidize, turn yellow, and possibly go brittle. The enclosed paper document becomes exposed to this oxidation and hydrolysis and can also become impregnated with the melted plastic or adhesive from the film. Removal generally follows methods associated with pressure sensitive tape removal- the use of solvents to swell or dissolve the film and/or the adhesive deposit. Heat can also be applied in a variety of ways to effect removal.
In this case, a combination of the two approaches is proving effective. Rather than applying heat from above, with a stream of hot air or getting in-between the materials with a heated spatula, I found that heat from below was the most effective.
Here’s the set-up, and another shot of it being used:
A conventional tacking iron that every conservation lab possesses is set to the lowest heat setting and stabilized in a face up position. Using the surface as a mini hotplate, the document is stabilized on the iron with a Casselli spatula in my left hand while I slowly pull the softened film away with the other. In this manner, strips are removed from recto and verso sides. The process takes around 45 minutes.
After film removal, the paper still appears translucent and darkened due to plastic that saturated the fibers. Testing of solvents reveals that an immersion in acetone for about 15 minutes reduces this effect by swelling remaining laminate substances and leaves the paper in a close to original state. Mending tears with tissue and wheat starch paste follows. Humidification and pressing completed the work.
Items find their way to the preservation lab in a lot of different ways. Sometimes new items are sent to us the moment they arrive and other times items circulate dozens of times before coming to us for a face-lift. Collection managers and librarians contact us when they have a special project planned, but occasionally someone just finds an old, beat-up book sitting on a shelf and sends it over. We have a lot of allies in the libraries looking out for us, but sometimes the only way to really know the physical status of a collection is to go and look over the whole thing ourselves. We call this a Collection Improvement Project, and our current collection of choice is the East Asian Collection in Herman B. Wells Library.
The East Asian Collection at Indiana University was begun in 1950 by Professor Ssu-Yu Teng, Professor Emeritus of History at IU. Dr. Teng came to the U.S. from China in 1937 and immediately began work at the Library of Congress as Assistant Compiler of Orientalia. His love of books and libraries would continue for the rest of his life, and provided the foundation and impetus for the formation of the collection at IU. One of his colleagues once remarked that he was a “walking bibliography” when it came to East Asian sources.
Dr. Teng received his Ph.D from Harvard in 1942, and went on to teach history at the University of Chicago, Harvard, and finally, IU. He was one of the few people teaching Chinese history in the U.S. at the time and is considered one of the founding members of Chinese studies in America. Dr. Teng began the East Asian collection out of need for materials to use in his own classes, but worked tirelessly his whole life to expand it. The collection now contains about 320,000 items pertaining to China, Japan, and Korea, and supports one of the top-ranking East Asian Studies departments in the U.S. Dr. Teng passed away in 1988.
The main purpose of the collection is to support research and scholarship. As Dr. Teng himself once wrote, “Just as lively fish without water would die, so a research scholar without access to books could perish.” However, this is not the only reason why these items are so important. About 59% of international students enrolled at IU in the Fall 2017 semester were from East Asia (China, Taiwan, Japan, or South Korea). For these users and their families, the collection represents a source of leisure and enjoyment, in addition to a research option. The collection also provides materials through interlibrary loan to universities all over the U.S., but especially to smaller Indiana universities without access to large collections.
When making our decisions about how to conserve these items, we must first consider how they are used. Our first step was to meet with the Librarian for East Asian Studies, Wen-ling Liu, who gave us insight into what users value most about the collection and where problems may be found. We learned that the collection is browsed heavily, so it is important to have spine labeling clear and visible. We will also avoid putting the items in an enclosure unless absolutely necessary, as it can hinder browsing. These items are also less likely to be available in electronic format and are often not replaceable. Some represent new challenges for us, such as new formats and unfamiliar languages. We plan to carry out the survey by going through the collection methodically, shelf by shelf, pulling items that need preservation. At the same time, we have taken note of particular areas of need and will pay special attention to those. It can take a long time to go through such a large collection, but by the end of it, we will rest easy knowing that this important piece of IU’s library collection will persist for many more years to come.
Indiana University Bloomington, Libraries. “About the East Asian Collection.”
IU Office of International Statistics
IU Department of Honors and Awards
John K. Fairbank, “Obituary: S.Y. Teng (1906-1988),” Journal of Asian Studies 47 , no. 3 (August 1988): 723-724.
With the pranks packed up and the chocolate rabbits devoured, you’re probably staring at your computer screen, sighing, and wishing it were Memorial Day already. But I’m here to tell you about one more celebration that you should get excited for! National Student Employment Appreciation Day is April 11th and this month we here at the lab are highlighting some of our awesome student employees and the amazing work they do for us.
Student workers are an incredible resource for universities like IU. Not only do they help us accomplish more than we could ever do on our own, they also bring in new ideas and attitudes that get us thinking about and questioning our established procedures, andgive us an opportunity to provide on-the-job training and experience to the next generation (I, as a former student employee, particularly appreciate this part)! Plus, they’re pretty fun to have around! But they don’t always get the recognition they deserve. We, at the Craig Lab, have had dozens of wonderful student employees over the years, but I want to take this opportunity to applaud our current four. So let’s check in and see what they’ve been up to lately!
Of course, our students do so much for us that anything I show you is necessarily only a small sampling of it. They are endlessly dedicated, inquisitive, and amazing! From all of us here at the E. Lingle Craig Lab, THANK YOU!
I recently mended and made folders for items in a Lilly Library manuscript collection. The collection contains the papers of Charles A. Halleck, who served in the U.S. Congress from 1934 to 1968. There was nothing unusual about the contents of one particular box, just original drawings of political cartoons and ads regarding the congressman from the mid-thirties. Then I looked a little closer at one of Halleck’s portraits.
The hatching in the illustration looks too good. It looks manufactured, not hand-rendered, but the perimeter of the shaded areas follow the form of brush strokes, just like on Halleck’s inked lapels. I found two other drawings of Halleck with the same perfectly hatched and occasionally crosshatched tones filling out the shadows on his face and neck. Fortunately, the backs of the illustration boards are marked “Craftint Doubletone,” so that’s where I started my search.
The Ohio-based Craftint Manufacturing Company offered Doubletone and a similar paper called Singletone from 1929 until they sold the product to the Ohio Graphic Arts Center, now Grafix. Grafix renamed the product Duoshade and it was available until 2009 when it was determined obsolete in the face of programs like Adobe Illustrator, and discontinued.
Twentieth century reference books and journal articles describe Craftint’s seemingly magical paper as an illustration board with a latent pattern on its surface that, when brushed with a liquid developer provided by the company, appears where desired. In these books, there is no mention of the chemical response in these latent patterns. However, as commercially successful products, I knew there must have been a patent on them.
After some digging, I found an application filed by Henry M. Baker in 1927 and patented in April 1929, the same year that Craftint started offering its product. Baker explains that by developing a silver nitrate image (a pattern of dots or lines) and blanching it with a substance like mercuric chloride to render it undetectable, a sensitized and lightfast image remains dormant until activated with a liquid developer.
Baker does not specify the chemical agent used to redevelop the pattern in his application. However, a patent issued to Carl Maier and William Swaysland in 1930 also listed on Craftint’s July 1948 product catalogue uses a different approach, by which a lead sulfate (lead white) pattern is applied to the paper’s surface and a soluble sulfide is brushed on where desired, turning the lead sulfate to lead sulfide, a dark compound. And if you made a mistake on the paper? Hydrogen peroxide would convert the lead sulfide back to a white compound. Other inventors built off Baker’s initial process, leading to various combinations of chemicals and developers.
A few detail images of Halleck’s inked portraits show the blank, undeveloped surface, the India ink drawing, and the developed pattern. Since these images are on Craftint’s Doubletone paper, there are two different patterns printed on the paper’s surface. Independently, the patterns make up two groups of parallel lines that, when both are activated, appear as crosshatching. A light tone developer makes visible one set of lines. For a darker tone, another developer is applied, but only after work with the light developer is finished.
What made Craftint toned papers so useful for twentieth century graphic artists? The potential to bring out large areas of tone with no more effort than a brush stroke is one of Craftint’s most attractive qualities. Compared to hand-rendered hatching and stippling, the results would be swift and concise, and mistakes were easier to hide via hydrogen peroxide than scraping or masking ink. Other methods of achieving tones and patterns were not always as effective and, in the case of halftone reproduction, not as affordable. Ben Day dots, as they are known now, did not offer the same precision as Craftint’s toned papers and had to be applied one large area at a time and burnished to complete the transfer of pattern, although they were available in a variety of colors. The tonal variety seen on and around Halleck’s mouth would have been difficult to achieve with Ben Day dots. Additionally, Craftint reproduced well at reduced sizes. A proof of Halleck’s ad shows the artist’s rendering reduced to smaller than one-quarter of the original. At such a size, the hatching on the original appears as a smooth, even tone across his face.
This process is very far from magic, though it surely seemed that way for artists. After dipping their brushes in clear liquid, the path of their brushstrokes immediately turned dark as it traveled across the paper. The phenomenon was easy to overdo, leading to images with many toned areas that, when reproduced into small comic strips and magazine ads, turned out cluttered and unclear. Artists commended peers who knew when to stop.
Anderson, Murphy with R.C. Harvey. The Life and Art of Murphy Anderson. North Carolina: TwoMorrows Publishing, 2003.
Baker, Henry M. Camera copy, and method of, and medium for making the same. 1709600, 1929.
Although she has been working alongside us since late summer, I’m only now introducing Janelle Beasley to our blog audience. Janelle is the Works on Paper Preparator at the Eskenazi Museum of Art here at Indiana University.
The art museum is currently undergoing renovations and will reopen in the fall of 2019. Employees were relocated to offices across campus and as the construction began, Janelle was welcomed with a cozy corner in our lab here in IU Libraries Preservation where she will reside for the near future. The lack of public exhibition demands is allowing her to perform some comprehensive rehinging and matting work on aspects of the Old Master print collections as well as modern and contemporary photographic works. Improved conservation facilities are on the list of changes at the museum- giving Janelle first-hand experience with lab space development too.
Janelle has been with the campus museum for several years now and brings to her position a wealth of experience from the commercial framing world. She’s adding to this by acquiring some new skills in paper conservation and preservation through workshop attendance and mini-lessons from us. It’s a win-win situation for us here in the lab too! We get extra company, and we can share some of our tips and techniques while looking over Janelle’s shoulder at the beautiful wood engravings and etchings she busies herself with.
I have recently discovered a sure-fire way to keep things interesting in my job: endeavor to repair books about photography. As a result of the recent closure of the Fine Arts Library, we have seen a high volume of materials from that collection. We wanted to see these things. The move of the collection presents an opportunity for us to sweep in and gather up materials that need attention. Add to that the fact that we spent a good deal of the summer working on a project to give some love to the Science collections. Where do Science and Art collide? Well, a heck of a lot of places, actually. For example:
Another way in which Art and Science come together is in books about photography. And what does any self-respecting photography book include? Pictures of naked ladies. Actually, it often doesn’t include pictures of naked ladies any longer, because they have all been stolen. It’s like an epidemic. Except that the illness occurred decades ago and we are only now discovering the casualties.
It’s almost exclusively naked ladies. Either people don’t want to steal photos of naked men, or the photos of naked men weren’t there in the first place, or the books with photos of naked men have been more closely guarded over the decades. There is probably a whole course in gender studies waiting to be taught on just this topic. (Photos of Michelangelo’s David don’t count. And they don’t go missing.)
Also, I’m not going to be including pictures of any naked humans in this blogpost, so don’t get all excited.
I recently took over the lab task of tracking down missing pages. Pages go missing from books for a whole host of reasons. Here are just a few, off the top of my head:
Someone really needed that article for their research paper and the book could not be checked out.
Someone really disagreed with that article and didn’t want anyone else in the world to read it.
The book is old. The adhesive on the spine dried up. Some pages just fell out.
Pet chinchilla ate the pages.
Someone forgot to bring money for the photocopier.
Photocopiers hadn’t been invented yet.
Someone had a really bad cold and forgot their pocket handkerchief.
That chart/map/table is just very useful to have on hand.
That picture is really pretty and someone wanted to put it on the wall in their dorm room.
That picture is of a naked lady .
Ok – let’s be clear here. Some of these things still happen, but many of these problems occurred in the past and are just coming to light now. When you have the font of all human knowledge AND a camera on the device in your pocket, you don’t really need to steal knowledge or images from the library any more. But sometimes pets do get out of hand. Books are continuing to age. Pages still legitimately fall out and get lost. Sometimes. But thefts perpetrated in decades past seem to be the most common reason for missing pages.
Tracking down missing pages is a bit like traveling into the past. You start to question the motivations of the person who took the pages. In most cases, you feel that someone just thought a picture was so lovely that they wanted to frame it and hang it on a wall. So they got a pair of scissors and hacked that sucker right out of the book and went on their merry way. I expect this does still happen occasionally. But it is now more likely that you would just Google image search that thing and then print your own copy. Or make it the wallpaper on your phone. We won’t even go into how weird if feels for me to talk about phones having wallpaper.
Let us take just a moment to think of the images that are on the other side of the picture of the naked lady. These baby goats, for example.
Think about all of the people who have been unable to appreciate this cuteness because someone just had to have the naked lady on the other side of the page.
Or, possibly, there is actually important text on the reverse and someone might now be missing a critical piece of information.
In some cases, the loss is too devastating for us to do anything about it. If the book is still in print, or readily available digitally, we might suggest to the subject librarian that the whole book be replaced. Sometimes, it simply isn’t worth our time to replace pages. But in many cases, the books are not so easy to come by, or would be perfectly all right if that one missing page were replaced. In these cases, I will go page hunting.
Here is a quick overview of the steps that might go into tracking down missing pages:
STEP 1: Figure out that there are pages missing from a book. This can happen when we do our first review of an item as it comes into the lab. Often, library staff or patrons discover that pages are missing and send the book on to us. This is most often noticed when someone sees sad stubs of pages that have been torn out.
Technically, people don’t discover the missing pages. They are missing, thus undiscoverable. What is discovered is the empty space:
STEP 2: Go through the rest of the volume to make sure that there are no other, previously unnoticed empty spaces. There very often are. Especially in books of photography. Extra especially in books of photography that include photographs of naked ladies.
STEP 3: Once you know exactly what is missing, look the book up on IUCAT to see if IU owns other copies of the book.
Nope, not that IU Cat.
If you are very lucky, then the book is out of copyright and available on Hathi Trust.
If you are very unlucky, the book is a bound copy of a popular periodical (Life magazine for example) with poor page numbering and no clear article breaks. It is difficult to place an interlibrary loan request (see Step 4) when you can’t specify which pages you need. Sadly, people love to take old magazine advertisements. I get it. Sometimes they are hilarious. And don’t have numbered pages.
STEP 4: Based on the availability of other copies of the book, make a determination of the best way to get a hold of another copy of the same edition of the book, and request that a copy be sent to you.
This is my chance to point out that I am not the only staff member involved in this endeavor. I have to work very closely with the staff in Document Delivery Services to solve these problems.
Below is a list of the most likely missing page situations and a quick description of how to proceed in each case:
Another copy is owned by a library at IU Bloomington -Either go to the library to find the book on the shelf, or request delivery through campus mail.
A copy is owned by a library at another IU campus. -Put in a delivery request through IUCAT to have the book sent through inter-campus mail.
A copy is owned by another library somewhere else in the world -Put in an interlibrary loan request through Document Delivery Services.
There is a scanned copy available online in Hathi Trust -Hope very hard that the pages you need are not also missing from the online copy. If they are there, celebrate, and download the relevant pages. Skip to Step 8.
The book is a periodical. -Document Delivery Services to the rescue again. In many cases, one can request electronic copies of specific pages. This is a lifesaver when it works. It is heartbreaking when the library at the other end sends the wrong thing and you have to bother the DDS people again.
There are no other copies available anywhere. -You are out of luck and there are no options left, because drawing your own replacement pictures or writing your own replacement text is not an appropriate option.
STEP 5: WAIT. The folks at Document Delivery Services will work all of the magic that they can to get you what you need. They are amazing and fabulous and friendly and helpful and deserve all of the superlatives.
STEP 6: Receive the other copy of the book you need. Compare the copies to make sure that the editions are the same, and to see if the pages you need are in this copy. Understand that if you are looking for missing naked lady pictures, 80% of the time the same pages will be missing from the copy from the lending library. If this is the case, contact the DDS folks and start the whole request process over again. Repeat as necessary. Sometimes this can go on for long time, getting one page from the University of Michigan copy and another page from the Purdue copy, etc.
STEP 7: If the pages you need are in the other library’s copy, then you may rejoice. Scan the pages from the replacement copy. Due to fabulous advances in technology over the last 20 – 30 years, we have a high- resolution flatbed scanner, which is an important piece of lab equipment. (Nominations are being accepted for the name-the-scanner contest. The winner will receive absolutely nothing except the satisfaction of knowing that they are very clever.)
STEP 8: Clean up the scanned pages in Photoshop and print out nice clean copies of the pages on acid free paper
STEP 9: Attach the copies into the original book. Additional repairs will often be needed at this point, so take care of those as well.
STEP 10: Send the book back out into the world with beautiful new pages and hope to goodness that they don’t just get ripped back out again.
Ok – After laying that all out, I guess my point is that this process is not quick. As with all of the other books that we handle, books with missing pages present a unique set of problems, and must be evaluated and dealt with individually. Books with missing pages take a lot more thought and care and work than many other books that we care for.
We love all of our books and will do our best for each of them. But for goodness sake, if you really, really need that picture, take a trip over to the digitization lab and scan yourself a copy. Or just take a photo of it with your phone. The folks at Document Delivery Services will thank you. And so will I. I’m tired of looking at naked ladies.
…would be just as useful. Following a recent orientation I gave for student employees within IU University Archives, it occurred to me that a microspatula can be just about as useful to archivists as it is to conservators. These small, hand-held pieces of metal with both rounded and tapered ends never fail in helping us with our jobs. I decided that an informal poster might be just the thing to spread the word to students and share with fellow conservators, so Paper Conservation Technician Hannah Helton and I set to work making one. The list certainly isn’t exhaustive (other uses range from spreading poultices and setting down flaking paint, to cleaning fingernails and using as a hair stick!) but you may learn a new tip nevertheless.
In the previous post, I mentioned some of the factors involved in choosing a consolidant for the job at hand. With this particular treatment I needed an adhesive that would obviously re-adhere flaking media, but I also needed one that would not dry with gloss on the relatively matte water-based paint Odets used, nor would I want one that would saturate the paint, causing it to appear darker where applied. Literature suggested both gelatin and isinglass would meet my requirements; I made some mock-ups to test the results and favored the isinglass.
So what is isinglass? It is obtained from the dried swim bladders of fish- in this case sturgeon- and is largely made up of collagen.
To prepare, one weighs out the amount needed and soaks it in water for 24 hours. The swollen mass is them mashed until pulpy and more water added to bring the solution to the percentage needed. It is finally heated to 55c for a short time. For an isinglass solution to be effectively vaporized in the ultrasonic mister, the concentration has to be quite low- in the 1%w/v range. This necessitates two or three applications for the consolidation to be successful.
Here are photos of the complete set up in operation-
Overall, the design developed back in the 1990’s functioned quite well. The parts were easy to procure through our campus chemistry storeroom (ringstand, three-prong clamp, LDPE bottle, tubing), Lowe’s (barbed connector to attach tubing to air compressor on suction table), and McMaster-Carr (fittings for the nozzle, and black rubber grommets to connect tubing to bottle*). This image shows a close-up of the nozzle held in my right hand. It features two reducing barbed fittings connected with 1/4″ tubing resulting in a 1/8″ stream of vapor.
From time to time, beads of condensed consolidant will form at the tip of the nozzle. In the above photo you can see a tube of blotter inserted into left side of the piece. Additionally, in my left hand I held a piece of blotting paper to absorb and drips that formed before they had a chance to fall onto the painting beneath. The biggest problem was with the airflow coming from the suction table compressor. The design has a 3-way T-connector placed along the supply tube before it enters the bottle. Its purpose is to bleed some of the air pressure off the hose so that it isn’t so great when leaving the nozzle as to blow away media flakes. I found the air pressure was still somewhat strong and required monitoring the angle and proximity to the artwork when in use. A much better, though more expensive, solution would be to attach some type of flow regulator to the air compressor valve on the suction table. Other than that, one other word of caution- it is important to flush the system after each use with water and air or the consolidant will build up in the tubing and nozzle. In the case of gelatin or isinglass (being organic) it could result in mold developing over time.
*other makers of this system have connected the tubes to the bottle with the use of hot-melt adhesives and epoxy. I found that the use of a grommet, with an inner diameter of the same size as the tubing or slightly smaller, gives a more effective and polished solution.
I’ve been busy the past several months in the Paper Lab getting together the parts, purchase requests and wherewithal to construct an ultrasonic mister in order to care for a group of paintings needing some attention.
Soon after the library received this gift, the Paper Lab hinged and matted nearly all of the paintings for storage and safer handling and access. During this process we noticed that a number of the artworks were suffering from condition issues related to the paint media that Odets chose. Much of the work relies on a layering method of drawing and painting over wax crayon. Odets would scratch through the pastel and gouache paints he favored to reveal the crayon beneath (a.k.a. sgraffito).
Here is a photograph of one such painting- on the back of a postcard- in raking light.
You can see how the teal blue paint has been scratched away to reveal orange, pink and purple wax crayon beneath. However, though the technique allowed Odets to create some wonderful images, it also created what we conservators refer to as inherent vice. There is little adhesion between the media layers and as the upper water-based paint layers dried, they began to shrink in place causing minute cracks and more seriously, flaking and loss. This close-up shows what I mean (poor little flaky fish!)
In these circumstances, conservators perform a process called consolidation. Typically, the consolidant is a type of adhesive carefully chosen for a number of factors including, but not limited to, compatibility with the object physically, visually and chemically, ease of preparation, ease of application, quality of bond strength and ageing characteristics. Normally, the process would be carried out under a low-power microscope using a small brush and delicately applying the consolidant to the cracks and underneath the lifting paint, fastening it back down. With these paintings the scale of damage prohibits such an approach- the fish above is 2cm long, which makes each of the tiny flakes far smaller than a millimeter in dimension. My fine motor skills are excellent, but not that excellent!
Another method is called for: that of Ultrasonic Misting. Developed by the Canadian Conservation Institute in 1990, the ultrasonic mister allows greater control of the whole process of consolidation of powdery paint and pigments. Unfortunately one can’t readily buy such systems- at least not at affordable rates for an aerosol generator- so I set out to construct one myself. There are a number of published articles explaining how to make one as well as a number of institutions who have blogged about it in the past, such as this account from the UCLA/Getty Conservation Program. Within a month or so I had purchased and cannibalized the necessary parts and had it up and running:
What the device consists of is a domestic ultrasonic humidifier, with the upper water reservoir removed. We use this very humidifier routinely in the lab for the relaxation of library materials, so it was good to have on hand! Resting in about one inch of water over the oscillator within the humidifier is a LDPE plastic bottle containing the consolidant adhesive. Ultrasonic frequencies generated in the base of the humidifier travel through the bottle and cause cavitation to occur, generating a fine mist of adhesive to rise from the liquid. A pump (the large white cube in the background to the left) was borrowed from our vacuum suction table to drive air into the bottle (through the clear tube entering the back of the bottle), and then the adhesive-laden water vapor finds its way out the top, through another length of tube to be emitted through a small applicator nozzle. Also sitting in front of the device is the consolidant of choice. Can you guess what it is? There is a clue in the painting I chose to include earlier…
Next week, I’ll cover the pros and cons of the design and talk about the success of the treatments.