- What we collect
- Preserving our collections
- Building our collections
- Selected Library collections
- Collection statistics
- History of the collection
- Processing and describing our collections
This 1913 letter from Bessie Rischbieth to her sister Olive Evans (MS 2004/1/7) and others like it have discoloured over the years as degradation products have built-up as a result of the composition of the paper and its exposure to environmental conditions such as light, heat, moisture, and pollutants. They are also torn in areas where the letters have been folded or handled, and the ink has burnt through the paper in areas causing lacing and fragility, making the letters quite delicate to handle without causing more loss or damage.
These letters are written in what appears to be iron gall ink, characterised by the brown tones, haloing, and burning or lacing of the concentrated or darker areas of ink. The presence of iron gall ink crucially influences the choice of a conservation treatment. Tear repair work is usually undertaken with water-based adhesives such as wheat starch paste and Japanese paper. However, this can be harmful for paper with iron gall ink inscriptions. When iron gall ink is exposed to moisture, the iron II ions, which are highly water soluble, can migrate throughout the location of the repair. Although these ions are invisible, once in contact with water they catalyse the chemical reactions that cause paper to break down and deteriorate. This reaction is not immediately visible, and it can take around 25 years before the damage is noticeable.
Although most iron gall inks can be characterised by their transformation from black to brown tones over time, they can also be deceivingly quite blue in colour, while on the other hand, poor quality carbon inks may also turn a similar brown. For these reasons, visual identification is not the only method for positive identification of iron gall ink. A non-bleeding indicator paper can be used to identify the presence of iron II ions from the tannic acid, which are harmful to organic substrates such as paper and parchment, and cause “lacing” of the paper.
Bathophenanthroline indicator papers are cut into small triangles, dampened with deionized water, and held on ink site for a number of seconds. We then inspect the indicator paper for any magenta colour as this shows the presence of iron II ions.
These beautiful letters tested positive for iron gall ink, which meant that the treatment to repair the lacing and tears requires as little aqueous contact as possible.
To avoid the movement of ions, remoistenable tissue was created in the lab by our trained conservators. A handmade Japanese tissue paper of a similar weight to the original paper was chosen and hand-toned to a matching colour, then coated with a 3% gelatin solution and allowed to dry. Once dry, the tissue was cut to shape and held face down on a small sponge covered with filter paper to ensure that only a minimal amount of water was absorbed. The repair tissue is only slightly damp, so that the gelatin is tacky, but the moisture will not spread from the repair through the ink and substrate. The repair was held down with the light pressure of a glass weight, which minimises movement of iron II ions.
The repairs are thin, yet strong and flexible allowing the paper to move without breaking, and can be removed if required with a light amount of moisture.
A project like the Suffrage Collection Project considers how access can be improved in several ways. By treating letters such as this one, fragile collection items are better protected for access by on-site researchers, but have also been stabilised for safe digitisation, which enables remote access and minimises the need for handling. Read more about the digitisation process for these letters in Part 3 of the blog series and the work done on the finding aid in Part 1.
The Suffrage Project has been made possible by donations from National Library Patrons and Supporters.