{"id":5700,"date":"2026-02-12T09:35:04","date_gmt":"2026-02-12T14:35:04","guid":{"rendered":"https:\/\/libapps.libraries.uc.edu\/thepreservationlab\/?p=5700"},"modified":"2026-02-12T10:14:36","modified_gmt":"2026-02-12T15:14:36","slug":"ovals-and-zs","status":"publish","type":"post","link":"https:\/\/libapps.libraries.uc.edu\/thepreservationlab\/2026\/02\/ovals-and-zs","title":{"rendered":"Ovals and Zs"},"content":{"rendered":"\n

How often do we pay attention to the framed portraits of important people and historical figures that hang on the walls of our institutions? Perhaps we glance their way every now and again, perhaps we even contemplate these forgotten ghosts briefly; but how often does a piece with its own provenance, characters, and stories simply become part of the everyday background, and how do we approach preserving these items, so they are not lost to history?<\/p>\n\n\n\n

Frame By Frame<\/strong><\/h2>\n\n\n\n

Recently I was assigned a framed portrait of German chemist and historian Hermann Kopp from the Oesper Collections in the History of Chemistry at the University of Cincinnati Libraries. It arrived with a similarly framed portrait of German physicist\/mathematician Gustav Kirchhoff, both of which were gifted to early UC chemistry department chair Thomas Norton in 1875 upon completion of his PhD at the University of Heidelberg. They would later become part of the Oesper Collections, and have been, for some time now, hanging on the wall of the library section since the collection was moved there in 1998, according to librarian Mark Chalmers.<\/p>\n\n\n\n

\n
\"Framed
The framed portrait of chemist and historian
Hermann Kopp, before treatment<\/figcaption><\/figure>\n\n\n\n
\"Framed
The framed portrait of physicist and
mathematician Gustav Kirchhoff, before treatment<\/figcaption><\/figure>\n<\/figure>\n\n\n\n

The Preservation Lab has received quite a few framed items from this collection as of late and the treatment\/housing requested by the selectors has become a common one that we practice. It involves scanning the original and printing a high-quality surrogate image of the photograph or print which can then replace it inside the original frame. The original photograph\/print can then be moved to a more archival storage option where it will be less susceptible to damage and degradation. A framed portrait of Marie Curie\u2019s daughter, Irene Joliot-Curie with an inscription from Ralph Oesper received this treatment and storage solution.<\/a> <\/p>\n\n\n\n

The Kopp portrait however, proved to require more creativity than prior framed items, and gave me an opportunity to try out a more unique storage solution.<\/p>\n\n\n\n

Kopp\u2019s Portrait<\/strong><\/h2>\n\n\n\n

The portrait was framed under several layers. From the bottom up, they included: a beige backing mat which the (likely) albumen print photo of Kopp was attached to, a thin piece of paper featuring an oval-shaped window with a golden border, and a thick brown textured paper, also with an oval-shaped window. These had been secured into a brown varnished wooden frame with painted gold inlays and a solid wood backing board held in place with rusty nails and metal brackets.<\/p>\n\n\n\n

\n
\"Framed
Kopp’s portrait seen inside its original frame before treatment<\/figcaption><\/figure>\n\n\n\n
\"The
The verso of the original frame before treatment<\/figcaption><\/figure>\n<\/figure>\n\n\n\n

Unfortunately, just about everything outside of the photograph itself is in poor condition. The entire matting system is extremely acidic and brittle with pieces of the brown paper window flaking off around the edges. There is also evidence that it has suffered water damage in the past.<\/p>\n\n\n\n

\"Bottom
The portrait’s matting system is extremely acidic and brittle; areas where bits have flaked off can be seen. Evidence of water damage can also be seen in the lower right corner.<\/figcaption><\/figure>\n\n\n\n

The Original Frame<\/strong><\/h2>\n\n\n\n

Although the wooden frame the portrait was housed in for years is original and part of the object\u2019s history, it is far from archival. With its varnished finish, rough wooden edges, and surface grime, it was likely doing more harm than good as far as the long-term preservation of Kopp\u2019s portrait; it could not remain in this frame. The frame is, however, every bit as storied as the actual photograph.<\/p>\n\n\n\n

Conditions such as those presented by this frame are a good example of why we often replace original items inside frames with surrogate images. This way, any potential damage or degradation caused by poor storage conditions will happen to a reproduction image opposed to the actual object.<\/p>\n\n\n\n

The Surrogates<\/strong><\/h2>\n\n\n\n

For this treatment, it was determined that two surrogates would be printed to be displayed in the Oesper Collection: one to take the place of Kopp\u2019s original portrait inside the frame which could then be re-hung on the wall of the library, and the other to be added to a display in the museum section.<\/p>\n\n\n\n

\n
\"The
One of the surrogates of Kopp’s portrait on
display in the museum section of the Oesper
Collections alongside Kopp’s four-volume series
Geschichte der Chemi (1843-1847), courtesy of Mark Chalmers.<\/figcaption><\/figure>\n\n\n\n
\"A
The other surrogate back in its original frame
re-hung on the wall of the Oesper Collections library,
Courtesy of Mark Chalmers.<\/figcaption><\/figure>\n<\/figure>\n\n\n\n

Jessica Ebert, Assistant Conservator at the Preservation Lab, and our go-to personnel for digital imaging, gently digitally retouched the image of Kopp, after consultation with the curator.<\/p>\n\n\n\n

\n
\"Photograph
The scanned image before digital retouching.<\/figcaption><\/figure>\n\n\n\n
\"Photograph
The scanned image after digital retouching; notice the absence of the spot to the right of his head.<\/figcaption><\/figure>\n<\/figure>\n\n\n\n

Storage Considerations<\/strong><\/h2>\n\n\n\n

As with earlier framed items we have received from The Oesper Collections, it was decided a matting system was appropriate for safe storage of the unframed portrait and its included parts. However, the brittleness of the items and some uncertainty about how the photograph would react to environmental factors presented some unique challenges. <\/p>\n\n\n\n

Although the mounting technique of placing them inside a polyester L-sleeve and mounting this with photo corners\/strips would be easy and fast, there was some concern that humidity could enter the sleeve and cause damage to the photograph\u2019s emulsion layer. Also, items mounted this way often need to flex and bend to a degree that these fragile materials likely could not afford.<\/p>\n\n\n\n

The Paper Cradle with Z-folds<\/strong><\/h2>\n\n\n\n

After considering these factors, Assistant Conservator Jessica Ebert suggested a paper cradle with z-folds. This mounting technique utilizes archival paper that is partially cut diagonally at each corner. Each edge of the paper is then folded over itself twice in opposite directions, creating a pocket for the edges of an object to rest gently inside.<\/p>\n\n\n

\n
\"Small
A small model of a paper cradle after the cuts and folds have been made.<\/figcaption><\/figure>\n<\/div>\n\n
\n
\"Illustration
Profile view of the pocket created when making the above folds; image from 2010 Art Conservator Tech Notes by Jennifer McGlinchy.<\/figcaption><\/figure>\n<\/div>\n\n\n

Once the cuts and folds have been made and the object is safely inside the cradle, the paper tabs extending off the corners of the cradle can then be mounted to a back mat using archival tape.<\/p>\n\n\n

\n
\"The
Once cuts and folds are made, the cradle features two tabs at each corner; these are used to mount the cradle using archival tape.<\/figcaption><\/figure>\n<\/div>\n\n\n

The Package<\/strong><\/h2>\n\n\n\n

We wanted to store both the photograph and its original brown paper window mat together inside of the paper cradle, but the acidity of the brown paper was still a concern. We determined that several protective layers should be included to prevent any acid migration from the brown paper to the photograph. All the layers inside of the paper cradle, affectionately referred to as \u201cthe package\u201d, are as follows, starting from the bottom up:<\/p>\n\n\n\n

    \n
  1. A piece of mat board to provide rigidity to the package.\n