Previously, we talked just a little bit about halides, and how they fit into the formation of silver gelatin-based images. Today, we’re going to take a closer look at part of the “how.”
Let’s begin with a brief overview of the darkroom process. As a reminder, the mechanics of creating a black and white print generally include the following steps:
A paper is pre-coated with a halide salt and silver nitrate that are mixed in a binder such as gelatin.
An image is first generated by projecting a source of illumination (like the sun or a lamp) through film onto a coated piece of paper.
Next, the paper or film is developed in a bath of chemicals. This is the part of the process the image seems to “magically” appear!
The image developing chemical reaction is stopped in a “stop bath.”
The paper or film is moved to a second bath to “fix” the image in a fixative bath.
The photograph is rinsed and hung to dry – ready to safely see the light of day.
Now, let’s delve a little deeper into the chemical reaction described in step two, beginning with a bit of a thought experiment. If I say to you, “semiconductor,” what springs to mind? Something involving electronics, perhaps? Maybe chips, lots of little circuits and tiny wires? Maybe, if you’re more photography-minded, a digital camera? All excellent things to think of! With this in mind, what if I told you that our silver gelatin emulsion is also a semiconductor, one that converts light into latent images instead of electricity?
Well, that is what we’re going to explore today, the basics of the mechanism by which light gets our emulsion ready to record latent images. The light shines on an atom (in this case, our silver halide ion), energy is transferred to an electron, and the electron moves to an excited state and is ready to make chemical magic.
If you refer back to your basic chemistry, atoms are composed of three parts: protons, neutrons, and electrons. Protons are positively charged and reside in the nucleus (center) of an atom with chargeless neutrons. Negatively charged electrons orbit the nucleus in bands. When all things are equal, an atom has the same number of protons as electrons, leaving the atom neutral. There aren’t a lot of atoms that are naturally like this, however; an atom will often have too many or too few electrons in orbit. This is a good thing, as it not only makes them stable, it makes them available for bonding with other atoms and creating chemical reactions.
Now let’s apply some of that to our silver halide. The electrons near the nucleus of our ion are in the “ground” state. They’re unexcited. The nucleus has them firmly gripped in its gravitational pull and they’re uninterested in going anywhere. This area of grounded electrons is known as the valence band. In order for them to be available for any sort of exchange, they’ll need to get farther away from that nucleus, and out into an outer band of the ion, conveniently known as the conductance band.
How does this all relate to the parking lots I mentioned in the title? I’m glad you asked. The parking lot analogy is a fantastic illustration of the process by which light interacts with matter. Let’s think of it this way: the nucleus of the silver halide ion is your typical Big Box Store. Directly outside of the store is the valence band parking lot, full of electron cars, all off, all waiting in the ground state. Beyond the parking lot is a strip of grass, which we’ll get to shortly, and beyond that is the conductance band (i.e, the road), where the cars are all in motion, on their way to any number of places.
The parking lot analogy, illustrated, from AIC’s Photographic Chemistry for Preservation, unit 2, “The Latent Image.”
In order for the cars to get out of the valence band, they’re going to need some energy. For our electrons, the needed energy is light. Once they get light to get the engines going, they can pull out of the parking lot and onto the road and drive off to chemical reactions.
Now let’s detour briefly to that grassy strip that I mentioned earlier. It’s known as the forbidden gap. Ideally, this area is empty. However, due to defects such as insufficient energy, an electron may not be able to completely cross to the conductance band, and may be temporarily stuck in this gap. Even here they can be useful as stepping stones for other electrons that need to cross over. Stuck electrons will either receive more energy to get them to the outer bands, or they’ll lose energy and be pulled back to the valence band.
I’ll note here that this structure is characteristic of all semiconductors, including digital camera sensors. In silver halide grains, this excitement of electrons will always happen when it comes into contact with light, as silver halide has a light sensitivity of 100%. No matter what, when a grain of silver halide is exposed to light, it will always liberate an electron. You also needn’t think of it as just one electron at a time being excited in this fashion. The grain can have so much energy that its valence band is completely empty, and vice versa.
What happens after this? Well, that’s an exploration for next time.
Hyacinth Tucker (UCL) — Bindery and Conservation Technician
We recently shared a blog post on the Cincinnati & Hamilton County Public Library’s blog that serves as a companion post to this one. Both posts focus on the repair of two CHPL books, Covered Bridges and When Art Meets Design, that received split-board binding treatments carried out by Kasie. While this post focuses on the treatment itself, the other illustrates the journey of a circulating book through treatment in the lab (and at home) and its eventual return to the library. We highly recommend checking out A Journey from Broken to Mended: Repairing Books in the Preservation Lab.
As a hybrid conservation lab, we treat and house both special collection items and general circulating collection items, as well as everything in between. Special collection items are rare or archival materials that typically do not circulate; basically, books and other objects that you can’t take home with you, are out of print, valuable, and/or are less readily available locally, nationally or even globally. General circulating collections are typically books that can be checked out and taken home, and tend to be newer books, books still in print, and/or more popular books. Since we are a collaborative lab that means that we treat and house special collections and general collections from both the University of Cincinnati Libraries (UCL) and the Cincinnati & Hamilton County Public Library (CHPL).
Due to the nature of these two types of collections (general and special), the treatment, documentation and who treats what is very different. Before the pandemic, most of the staff’s time was dedicated to special collection items or the items that fall between the two categories, which we call medium rare, and our students and volunteers, with plenty of hands-on, one-on-one training, handled the bulk of our general collection repairs. But then working from home, all or a majority of the time, became the norm for Lab staff and we had to shift focus and turn to taking on more general collection repairs that we could more easily take home with us. Initially, we took home more difficult sewing projects and mending projects that our students or volunteers either hadn’t gotten to yet or were avoiding for one reason or another. Then, after we could return to the Lab in some capacity to prep our own materials, we realized that split-board bindings* were the ideal general collections treatment for staff to work on from home.
A split-board binding is a new binding or case that incorporates several newly added reinforcement elements that are then sandwiched between two pieces of board that make up the front and back covers.
Kasie’s split board binding cutaway model
Each technician has a cutaway model that they’ve made, so they can easily reference it during treatment.
With the cutaway model you can see the various aspects of the treatment.
Split-board bindings are a great solution for oversized, heavy books like coffee table books and art books with glossy pages, which are very common in both UCL and CHPL general circulating collections. They are also, by far, the most complex general collections treatment we perform in the lab and have always been done by the conservation technicians, instead of our students or volunteers. This is not only because of the complexity of the treatment, but also because of the lengthy treatment time involved; a student or volunteer’s limited weekly schedule in the lab is not conducive to such an extensive treatment. Though it was a general collections treatment reserved solely for the conservation technicians, prior to March 2020 the techs unfortunately had little time to work on these treatments, as our focus was primarily on special collections treatments and housing. Therefore, we had amassed a little backlog of split-board binding treatments – enter quarantine and working from home!
One question that might come to mind, if split-board bindings are so elaborate and extensive, why do them on general collections items at all? Why not just buy a new copy; wouldn’t that be more cost effective? Typically, the books that warrant a split-board binding are more pricey, glossy paged, oversized books, like art and architecture books. And unfortunately, though these books have a much higher retail price than your average James Patterson novel, the construction is generally less than ideal. These books might have beautifully printed, full-color, thick and glossy pages and dynamic cover art, which makes them attractive to the reader, but they also are often sewn with very thin, fragile thread that easily breaks. The spines are generally lined with a layer of rigid plasticized glue that can become very brittle over time. Often, the covers or cases are constructed solely of printed paper, not cloth, and generally have a thick piece of board along the spine (which we call a flat back) that doesn’t allow the book to flex properly when opened and can actually make the spine break down and tear in record time. It is not uncommon for these books to have little to no reinforcement in the attachment of the textblock to the binding (i.e. how the block of pages is attached to the cover), which makes the heavy textblock break away from the cover quite easily with use.
Textblock broken away from the cover
Example of plasticized adhesive that has failed, leaving the textblock unsupported
Example of plasticized adhesive that has failed, leaving the textblock unsupported
Textblock detached from cover and textblock not properly supported
But why are these books constructed so poorly? These large coffee table and art books are constructed with individual use in mind, not with the frequent use and circulation that comes with a library collection item. The split-board treatment, along with many general collection repairs, improves on a bad binding design and makes the book stronger and sturdier, using better binding techniques and materials that can better stand up to use by many library patrons.
A split-board binding treatment involves creating a new binding with new sewn-on endsheets that are reinforced with cloth, at least three sewn on linen tapes (supports), new spine linings, and a new quarter bound case created with two boards at the front cover and two at the back cover, and generally an inlaying of the original cover designs. However, additional elements of treatment may be warranted based on the condition of the book, such as broken sewing, tears, detached leaves, etc. The steps generally proceed in the following order:
Prepare materials in the Lab – new endsheets, starched reinforcing cloth, linen tapes, spine linings, binders board, bookcloth and Bristol board for inlays.
Detach textblock from cover, if needed.
Remove original spine linings, mechanically and with poultices.
If broken, remove original sewing thread and disbind textblock.
Mend any tears and guard any separated, torn or detached leaves.
Sew to include linen tape supports and new endsheets using French link stitch – whether partial/added sewing over the original sewing or complete resewing is dependent on whether the original sewing was intact or if it was broken and the textblock disbound.
Round and back spine, as needed.
New spine linings adhered to the spine:
Reversible layer of kozo fiber tissue with wheat starch paste.
Original stuck-on endbands, if present, or new endbands.
Cloth reinforcement lining (Cambric) with flanges that extends past the spine on both sides.
Several paper linings to further support the textblock.
Create “laminated flanges”, the key characteristic of a split-board binding, using the sewn on linen tapes, the flanged cloth piece adhered to the spine, and the first and last leaves of the new endsheets. Cut laminated flanges into thirds, with the center portion incorporating all the linen tapes.
If the original covers included artwork that should be retained, mechanically remove from the original boards. Remove remaining board backing with poultice.
Remove and clean the original spine.
Cut binder’s board to size – 2 pieces of board are cut for both the front and back covers (4 pieces total). The thickness of the boards used is dependent on the shoulder of the book.
Determine placement of the board and adhere the middle laminated flange segment to the top of inner board, keeping the top and bottom laminated flange segment under the inner board, unattached. Adhere the outer board to the inner, thus sandwiching the middle laminated flange section between the two boards.
If the original cover is being inlayed, create and attach an inlay border of thin Bristol board to the cover boards, as needed.
Covering the boards:
Attach the spine cloth piece and turn in at the head and tail.
Attach the board cloth to the upper and lower boards and turn in the edges.
Bevel the remaining laminated flanges and sewn on cloth reinforcement (Cambric) slightly and attach both, in sequence, to the inner boards.
Adhere the pastedowns and trim the remaining sewn on Cambric to roughly 1/8” – ¼”.
If there are cover inlays, adhere the inlay(s) to the cover(s) within the inlay border.
Adhere the original spine to the new spine of the case.
Preparing materials in the Lab
Using the board shear to cut bookcloth for the covers
Ready for treatment at home
Cleaning the spine
Removing original adhesive
Textblock fully disbound
Mending & guarding
Sewing the textblock
Sewing on linen tape supports
Newly resewn textblock
Rounding & backing the spine
Reversible layer
Cloth reinforcement layer
Preparing paper layers
Fully lined spine
Creating the laminated flanges
Creating the laminated flanges
Prepared textblock
Preparing cover inlays
Removing original cover art
Removing the backing from inlay
Cutting the boards to size
Attaching the inner board
Inner board attached
Outer board attached with laminated flange between boards
Attaching inlay boarder
Adhering spine cloth
Turning-in spine cloth
Adhering cover cloth
Attaching laminated flanges and cloth reinforcement
Adhering pastedowns
Pasting out inlay
Attaching inlays
Trimming inner cloth hinge
Adhering spine title
Completed treatment
When completed the treatment offers a substantial amount of support to the textblock and a robust attachment of the textblock to the new case. While it is an involved treatment that requires a good amount of preparation, work and skill, the end results are worth it all, and the improvements are significant.
Treatments of this magnitude take many, many hours over the course of several weeks. Often, only a few steps of the treatment can be accomplished at a time to account for drying time, and timing out visits to the Lab. To take a sneak peak at what some of the steps of treatment look like please check out the video below:
For an example of how Kasie used a split-board binding treatment and modified it for a special collection item that came to the Lab from UC’s Winkler Center without a case, check out her blog, A Monster of a Treatment.
We hope you’ve enjoyed this peek into a split-board binding treatment! If you did and you want to see more of what we do, and see the Lab, then please check out our Virtual Lab Tour which will take place on Tuesday, January 26th at noon, live on the Cincinnati & Hamilton County Public Library’s Facebook page. For forthcoming information about the Virtual Tour follow the Public Library on Facebook and follow the Lab on Instagram (@thepreservationlab).
*This treatment was originally designed at the Brigham Young University lab. Then it was brought to the University of Kansas lab by Brian Baird, where our conservator, Ashleigh Ferguson Schieszer, learned the treatment and thus brought it to the Preservation Lab.
The purpose of this blog is to show a relatively easy long-term solution for strengthening and protecting the packaging for shallow banker’s box enclosures. There are two notable benefits to using this solution. The first being that in some cases little to no repairing needs to be done to damaged parts of the box and the second is at no time does any adhesive come into contact with the original piece. I have developed this system down to a science. If I make my measurements correctly, from start to finish, the lid and base jacket can be made from the custom stencils in about 180 minutes.
Ultimately you’ll be cutting 2 pieces of 4 mil Mylar to the following dimensions (W+thx4+4inches x H+thx4+4 inches) with the help of stencils.
To make a stencil I just place the lid in the center of the wastepaper and adding about 1mm all around, trace the width and height. Add 1 wall thickness all around followed by 1 wall board thickness all around then another wall thickness all around. Draw each of these added lines all the way to the edge of the paper.
You may notice little adaptations to the tabs that will be cut out of the Mylar. I make the tabs on opposite sides to create symmetry. Here is a close-up of one.
After scoring and cutting out the Mylar to match the pattern, fold on the lines using either a ruler and bone folder or your fingers.
When you are all ready, place the box in the center of the Mylar sleeve and place double stick tape where the tabs will secure the corners. Start with the outside corners first.
One of the great qualities of this protective wrapper is that it can cut out repair time by the virtue of the strength of the wrapper itself.
Secure the rest of the outside, then inside corners, and we’re done!
Now it’s time to enjoy the music.
Chris Voynovich (CHPL) — Senior Conservation Technician
Poisonous Book Project
In the Victorian era, textiles were colored with a green copper aceto-arsentite, used from 1814 to the late 1800’s. (Side note: this green is sometimes referred to as Paris green or emerald green and was widely used by impressionist painters.) And since books were bound in textiles, it’s no surprise that these vivid green cloths were used to bind publisher’s bindings. Therefore, it’s entirely possible that these copper arsenic covers are lurking within our library collections dating to the 19th century. In 1855, Viridian green was invented which eventually replaced Paris Green; therefore, green cloth bindings from the 20th century to today are of likely no concern.
When faced with the question of how to ID these textiles in the past, I’ve referred researchers to textile conservators who may be more familiar with this subject – as well as paintings conservators since they deal with pigments on a regular basis. The best resource on the subject I could track down was an adjacently-related conservation study on Navajo Textiles, titled, Coping With Arsenic-Based Pesticides on Textile Collections by Jae R. Anderson, Nancy Odegaard, Martina Dawley, Delana Joy Farley, and Werner Zimmt from the American Institute for Conservation ‘s Objects Specialty Group Postprints, Volume 21, 2014.
However, new research being conducted by Melissa Tedone and researchers at Winterthur Museum, Garden & Library shines new light on the subject. They provide helpful recommendations on ID, handling, and storage. Please see https://www.iiconservation.org/content/poison-book-project to learn about the Poisonous Book Project being performed by Winterthur Library.
While our lab does not currently perform x-ray fluorescence spectroscopy to confirm whether a book is poisonous, there are some visual clues to be aware of. When handling a copy of Rustic Adornments for Homes and Taste (1857) Melissa Tedone notes how “the bright green colorant flakes readily from the bookcloth with even the gentlest touch of my porcupine quill.” This pigment seems to be impregnated into the cloth rather than dyed, and therefore prone to brittleness and flaking.
Recommendations to those without the ability to ID pigments: If you suspect that your book may be bound within the Victorian era of the 19th century, treat the book as though it may contain arsenic.
Place it in a polyester or polypropylene jacket and house it inside an enclosure.
Handle it with gloves that are disposable or are washable
When handling, lay it out on a table with paper liner that can be disposed of after use (or clean the table after use)
If you are in need of a box for storage, University Products and Talas are great resources for purchasing archival housing supplies.
Additional recommendations for libraries by Melissa Tedone and the Winterthur crew include:
Digitize bindings to provide researchers a non-toxic option of handling these texts
Identify and store these books together in one location within collections storage. If these materials are affected in a potential flood or disaster, this will help to streamline handling and containment of these dangerous materials.
Curious to know if there are specific titles of books that have tested positive for “poison?”Check out this link for a table of books identified by the Poisonous Book project and compare against duplicate titles in your collection:
Since testing continues, the Winterthur research team has created a color swatch bookmark to assist with identifying potentially arsenical green bookcloth. The library asks for the consideration of of $5 or more to help cover printing and mailing costs. Email reference@wintherthur.org for more information.
To learn more, check out the 2023 Connecting to Collections (C2C) Care Webinar The Poison Book Project.
Ashleigh Ferguson Schieszer (CHPL) – Rare Book and Paper Conservator, Lab Co-Manager
As you might imagine remote work for a preservation lab is…complicated. Not all items awaiting treatment are good candidates for repair in the home studios of staff – the repair might require specialized equipment that is only available in the lab (e.g. suction table), the item may be too valuable to transport to a private home without engaging UC risk management and CHPL administration (i.e. all our special collections!), or the object may be too large to safely be worked on in our diminutive setups (e.g. many books with the folio designation).
But, that doesn’t mean that work from home isn’t happening! The image below is a batch of completed treatments awaiting return to our partners. These treatments are general circulating items that have been repaired, as well as items receiving custom enclosures created without the object, using just the objects measurements. The materials have been treated from home and now, on our new abbreviated lab schedule, are being end processed and returned to their originating institutions.
Though we all deeply miss the day-to-day work in the Preservation Lab, remotely we maintain our ethos of preservation stewardship keeping us connected to the lab’s preservation mission and the missions of our parent institutions. In this, we remain unchanged.
University of Cincinnati Libraries (UCL) and Cincinnati and Hamilton County Public Library (CHPL) materials awaiting packing for delivery.
The Ohio Preservation Council has updated grant procedures andawards to reflect the current emphasis on remote learning and virtual conferences.
In 2020, the Ohio Preservation Council will offer four awards of up to $250 each in support of continuing education for Ohio Students and Professionals with an interest in preserving our cultural heritage. Applications will be accepted on a rolling basis and awardees will be notified after the 3rd Thursday of: August, September, November, December. Full details can be found here.
The Ohio Preservation Council serves as a coalition of preservationists, conservators, librarians, archivists, curators, records managers, the institutions they represent, and other concerned citizens who recognize the serious threat to documentary heritage. The Council’s mission is to provide a network for preservation education and to support preservation activities within the state of Ohio. The Council believes in cooperative, state-wide efforts across geographic and professional lines are needed to meet preservation challenges.
The Ohio Preservation Council recognizes the value of professional meetings, conferences, and other educational opportunities to advance the field of preservation and provide a forum to voice the need for ongoing stewardship of our documentary heritage. When possible, the OPC shall provide financial support to individuals to develop skills, expand knowledge, and gain experience relevant to the mission and goals of the Ohio Preservation Council. Applications are due the first Mondays in March and September.
Individuals requesting financial support must meet the following criteria:
• Working in the state of Ohio OR pursuing an advanced degree or certificate in the state of Ohio;
• Working directly in the field of preservation (as described above) OR pursuing a degree or certificate within the field;
• Request is for professional development that clearly relates to preservation issues and/or preservation skills;
• Have not received financial support from the OPC Grant within 3 calendar years.
You might know the importance of a protective enclosure, but how often to you consider the quality of storage materials? In fact, the composition of storage materials plays a significant role in the preservation of archival collections. But how?
Since storage plays a passive role, the positive and negative interactions of storage materials may not be readily apparent. Chemical reactions that occur between library and storage materials are often a slow process, spanning over a number of months or years before a visual change occurs. Without the gratification of seeing immediate effects, many may not realize how some storage materials can be problematic, let alone the ramifications for using non-archival materials.
To illustrate some of the effects, I thought I’d share a vivid example of protection from acidic materials during storage. The following photograph shows the positive effects of archival buffering paper (also known as interleaving), as well as the danger of using non-archival boards and tapes – even when they are not in direct contact with the object!
The protected object is a 17th century printed broadside. It’s a single sheet of paper with printed black text on the front. The broadside was stored for many years in a green cloth-covered portfolio.
Within the portfolio, the broadside was secured beneath with folded sheets of plastic film with a blank sheet of paper. You can see the plastic film is attached to the portfolio around the edges with green tape.
This image shows the front of the blank sheet of paper stored side the plastic film, below the broadside. The plastic has yellowed overtime.
Here, the blank sheet is removed, revealing yellowish-brown discoloration around the top and right edge. This discoloration aligns perfectly with the green tape that is adhered on top of the plastic –located on the top and right side of the plastic.
When you flip the paper over, the back of the blank sheet shows even more discoloration. In fact, the discoloration is a mirror image of the materials below the plastic! This has occurred because the plastic is “breathable.” The materials below are all acidic, except for the white fragments of paper, which protected a portion of the paper from turning brown.
The interleaving paper served two purposes here:
Acts as a support for the broadside when handled.
The interleaving served as a sacrificial barrier that absorbed the bulk of acidic off-gassing from the non-archival paper and tape.
In summary, this enclosure is an excellent example of how different materials can interact with one another in nuanced ways, and how plastic is actually a permeable barrier to gasses overtime!
General storage tips:
When placing interleaving within an archival polyester L-sleeve, make sure the interleaving tissue is larger than the object so you can avoid localized discoloration
Architectural prints, blue prints and some photographs are special. Don’t store these in buffered materials (materials that are above pH 7). Store them with pH neutral materials like polyester film or unbuffered paper.
Check out these resources on selecting archival storage materials:
Our conservator Ashleigh Ferguson Schieszer will be assisting paper conservator Jamye Jamison in an upcoming Ohio Preservation Council workshop. Seats are still available! Workshop description: This course is for archivists, librarians, or anyone who is interested in caring for their family documents, print collections, or other ephemera. The class will begin with a short discussion of materials and what to look for when making archival enclosures for flat paper objects. Each participant will then make a small portfolio of reference samples of various enclosures for paper materials, including a simple four-flap, polyester sleeve, paper envelope and a “back and wrap” enclosure, which can be used for display. Each participant is asked to bring four objects no larger than 4 x 6 inches (roughly postcard size) that can be used to make the reference samples. No previous experience necessary.
Learn more and register at —- http://opc.wildapricot.org/event-3357153
Our colleagues in the Classics Library sent us an interesting housing project. The goal, to secure and keep together a textbook and accompanying electronic content.
The additional electronic content was not in the form of a URL for on-line supplements, nor a DVD, but a small shiny USB drive. The drive was originally attached it to the book at the end of a long silky bookmark adhered to the text block. A neat idea, but the drive was almost impossible to use attached to the anchor of the heavy book.
Ah, the mashup of the old and new!
Our solution was to make a simple corrugated enclosure with a volara foam compartment and a photographic surrogate on the end of the bookmark. The surrogate directs users to the compartment holding the USB port. Additionally, a message in the item record alerts library workers to “check for one USB device”.
To me the pleasure of this item is that it illustrates so clearly the tension between the easy functionality of the book and the limits of its fixed form. It also speaks to how slow the march towards the digital age feels – illustrating a change in technology without much of an improvement, such as the move from DVD to USB storage.
[And here is where I lament that I STILL don’t have a hovercraft or a robot maid.]
Though many of us have vowed to get out of the prediction game, let me predict in 10 years our students will marvel at this USB device the way they do now at floppy disks and zip drives.
LONG LIVE THE BOOK!
Enclosure by Jessica Ebert, conservation technician
Check out this new article about the work of the Preservation Lab by our collaborator Melissa Norris, with assistance from Ashleigh Schieszer, Jessica Ebert, and Kevin Grace at https://libapps.libraries.uc.edu/source/preserving-taft/.
Isn’t Preservation just so cool!
Ashleigh Schieszer works on Taft’s maquette. (Photo credit Jessica Ebert)
And for our loyal followers a bonus image of the housing of the William Howard Taft letters…
Encapsulated binding by Chris Voynovich, design by Ashleigh Schieszer (photo credit Jessica Ebert)
