45th Annual Meeting – Book & Paper Session, June 1, 2017 – “Ionic Fixatives on Water-Sensitive Media for Aqueous Treatment” presented by Soyeon Choi

In her talk on ionic fixatives, Soyeon Choi, head conservator of works on paper at Yale Center for British Art, presented an overview of the history of ionic fixatives, an explanation of how they work, and the results of several experiments.  I had been looking forward to hearing Soyeon’s talk, due to the potential usefulness of ionic fixatives for library and archives materials.  As Soyeon emphasized throughout her presentation, this type of fixative is likely to be most useful in cases where saving the information is a higher priority over aesthetic appearance, such as in the case of modern and contemporary inks, which are sensitive to a wide range of solvents.  Soyeon’s experiments focused on a wide range of inks and included a variety of tests with numerous ionic fixatives and several different contemporary inks.

Prior to this talk, I hadn’t realized that ionic fixatives had remained more popular in Europe than in the United States since they were introduced as a treatment technique in Germany in the 1980s.  As Soyeon explained, ionic fixatives have been used for mass scale treatment in Germany since 1996, but simply have not caught on in the US, for a number of reasons.  One of the main challenges in translating this technique into practice is that these fixatives are industrial products which are used in processing textiles, and are not commercially available on a small scale.  A related challenge is that the names of the fixatives are proprietary, and therefore vary from country to country, so fixatives used for research and testing in Europe are either not available in the US or go by different names.  And, as with all things industrial, the exact composition of these fixatives is proprietary and subject to change.  Soyeon felt it would be useful to complete a study of ionic fixatives in the US, and having seen her talk, I agree!

Soyeon gave a brief and thorough description of the main categories of ionic fixatives, which can be either cationic or anionic, and explained how these differ chemically.  Interestingly, it has been found that cationic and anionic fixatives work best when used in tandem rather than when used separately.  She also explained that the main drawback of all ionic fixatives is that some permanent change in the color of the ink should be expected, and that these are most useful in situations where preserving legibility is the main goal.  Her research focused on dye-based inks, and compared 13 different fixatives.  The experiments included examining the effects of applying the fixatives, and then testing the efficacy of the fixatives using localized treatment.

The goal of the first experiment was to determine if the fixatives leave any residue in the paper after washing, and to see if it made any difference to wash before or after the fixatives dried.  Whatman filter paper was used, and the fixatives were applied to the paper on their own, as in not over any ink.  Samples were left either unwashed, washed before the fixative dried, or washed after the fixatives dried.   The fixatives tested included Polymin, Lupamin, Cartafix FF, Cartafix SWE, Cartafix WA, Cartafix WE, Cassofix FRN, Catiofast 159(A), Catiofast 2345, Mesitol NBS/Rewin EL, Nylofixan HF, Catiofast 269, and Appretan.  The samples were washed for 15 minutes, and were examined for fluorescing residue and compared under UV light.  There was a range of results in terms of fluorescence, and the fixatives which showed little to no fluorescence were chosen for further experiments.

In the next experiment, the effect of accelerating aging on the washed samples was examined.  In this experiment, unwashed and washed oven-aged samples were compared.  The oven-aged samples were aged at 70oC, 50% RH for 96 days. The fixatives used were Catiofast 159(A), Cartafix FF, Cartafix WA, Cartafix WE, Catiofast 269, Lupamin 9095, Catiofast 2345, Nylofixan HF, and Mesitol + Rewin.  The samples were examined in visible and UV light.  One fixative, Nylofixan HF, stained the paper even without aging.  The not washed oven-aged samples developed significant amounts of fluorescence, but the washed, oven-aged samples did not, which suggests that washing did a good job of removing the fixative.

Based on these initial test results, three fixatives stood out as the most viable, including Cartafix WE, Mesitol & Rewin, and Cartafix FF.  These three fixatives were then tested with contemporary inks. The inks tested, included Winsor & Newton Calligraphy Ink, Bombay India Ink, and Higgins ink.  The fixatives were applied over fixed and unfixed inscriptions, again on Whatman filter paper. The fixatives were mixed with methyl cellulose and applied on a suction platen to both the front and back of the samples prior to washing.  Both fixed and unfixed samples were washed.  As expected, the unfixed samples bled profusely.  Most of the fixatives gave acceptable results, and some fixatives worked better with certain inks.  Higgins ink did not do well with any of the fixatives.

As Soyeon summarized, there are many factors to consider when using ionic fixatives, and their use requires a lot of fine tuning.  The fixatives permanently alter the media to some degree in terms of hue and saturation, and rinsing is important for long term stability.  The fixative names change fairly frequently.  Future tests may include the use of ionic fixatives with blotter washing vs. immersion washing, gel vs. solution application, and air drying vs. quick drying.  Overall, I thought the experiments were helpful and thorough.  There was a lot more information presented than I was able to capture, so I hope that Soyeon publishes this work someday.