There are many types of translucent papers, each with its own set of conservation issues stemming from various manufacturing processes. The characteristic that makes them stand apart from other papers—transparency—can itself be at risk when there is a need for applying mending or lining tissues. This project explores the physical and chemical aspects of paper transparency. It investigates the concept of optical clearing (transparentizing) of repair tissues to achieve appropriate repairs on translucent papers without dramatically increasing the opacity of treated areas. The term “optical clearing” is borrowed from biology and medical research; it refers to the process of rendering biological tissues transparent through the application of clearing agents, which minimize the scattering of light and allow greater visibility for microscopy and imaging. This method is similar to some historical processes of transparentizing paper, when papermakers added oils, waxes, and rosins to fill light-scattering interstices, allowing more light to travel unimpeded through the paper web. This concept is applied to conservation repair tissues with the goal of determining a coating to serve dual functions: optical clearing agent and reactivatable adhesive.
A wide range of adhesives and coatings familiar to paper conservation were tested for their transparentizing effects on various repair tissues, including traditional Japanese papers and nanocellulose papers. Opacity measurements were taken using a spectrophotometer and the contrast-ratio method. Acrylic polymer dispersions proved to be the most consistently successful clearing agents. This can be attributed to the superior film-formation qualities of the acrylic dispersions and their amorphous polymeric structure. The heat-reactivation capability of acrylic adhesives also proves advantageous for treating translucent tissues, which tend to react dramatically to moisture.
A range of repair methods was applied to modern translucent tissue samples. These were measured for opacity before and after treatment to compare to repairs made with cleared tissues. SEM cross-sectional imaging was used to visualize adhesive penetration. Attempts at removing each repair were also made to characterize ease-of-reversibility.
The long-term stability of optically cleared repair tissues is considered alongside an aging test that measures the yellowing and turbidity of acrylic transparentizing coatings under different light exposures.
This project was presented at the 2018 Annual Meeting of the American Institute for Conservation and appeared as an article in the subsequent Book and Paper Group Annual.
Williams, Roger S. 2018. “Optically Cleared Repair Tissues for the Treatment of Translucent Papers.” Book and Paper Group Annual 37: 96–110.
The adaptable conservation book support (ACBS) is a tool designed to hold books of various sizes and shapes open at any desired angle. This allows conservators to treat the interior (either the binding or the text block) of books that cannot open safely, either due to a fragile binding or degraded paper. It can also be useful for digitization and scientific analysis of the interior of text blocks.
The ACBS is a DIY, open-design tool. A supplies list and assembly manual are available on the AIC Wiki, so anyone can build their own. Other conservation professionals can also make adaptations or design suggestions—the ACBS is a collaborative work-in-progress. The original design was created with the help of engineering undergraduate students in Northwestern University’s “Design Thinking & Communication” course. Here is a presentation made for the Icon “Together at Home” series about the project.
Since the project began, preservation professionals have built ACBS models in Australia, Germany, New Zealand, the UK, and across the US. In summer 2020, a team at the Auckland War Memorial Museum Tāmaki Paenga Hira designed a set of 3D-printed parts for the ACBS. Their design improves the clamping system and allows the clamping rods to change angles. Here is a blog post about their work.
The ACBS grew out of research on shimbari clamping—the ACBS clamping device incorporates the same flexible fiberglass rods used by some conservators for shimbari.
Scaleboard was a material used in a range of industries—primarily in the manufacture of hat boxes and bandboxes—during the seventeenth, eighteenth, and nineteenth centuries. The material is simple: thinly sliced wood, usually oak or beech. Though box-making was its primary use, bookbinders also used it as a material for bookboards in Western Europe and the early United States.
Because of its sheer thinness (typically 1 to 2 mm) and flawed grain (a result of its mass production), scaleboards often suffer from significant losses. These losses can leave the book's text-block exposed and at risk.
For the most part, losses to scaleboards can be dealt with through proper housing. Depending on a book's usage, though, it may be decided that a loss replacement needs to be performed. This project explores a loss-replacement technique borrowed from furniture conservation: a bulked epoxy fill with a reversible barrier layer (gelatin).
The epoxy repair method was subjected to two tests: a load-bearing test and a reversibility test, to determine the most appropriate concentration of barrier layer. It proved successful, and the method was applied to a nineteenth-century school primer possessing scaleboards.
Shimbari is a Japanese term for a clamping method using flexible sticks, which are placed between the target area and a rigid frame. The amount of pressure applied can be adjusted by changing the distance between the target area and the frame. Shimbari is unique in its precision and adaptability—pressure can be applied at virtually any angle and to small and hard-to-reach areas.
In book conservation, professionals rely on various tools—weights, clips, clamps, presses—to apply pressure. However, books are complex, three-dimensional structures, and some areas simply don’t work with these tools. Shimbari is great for applying pressure to areas deep in a book’s gutter or to narrow surfaces such as endbands, spines, and board edges. It can also be employed to help reshape parchment in challenging areas, such as on yapp edges.
Shimbari is used in other conservation fields like furniture conservation. When treating such large objects, conservators often need to construct custom shimbari frames. However, in book conservation, we already have an appropriately sized frame: the sewing frame.
