Adhesives for paper conservation
This one-day course, held at Tate Britain on 23rd March 2015, was tutored by Velson Horie, Collection Care and Conservation Consultant (www.horie.co.uk). It was divided into two main parts: theoretical in the morning and practical in the afternoon. The participants were 16 conservators mainly from book and paper conservation backgrounds, from both institutions and private practice.
In the morning Velson went through his PowerPoint presentations, starting with an overview of the objects to be treated and the materials added during treatments, criteria for choosing, reversibility, and polymers and their properties (molecular weight, glass transition temperature, chemical interaction and reactivity, mechanical strength and optical properties).
Before the lunch break, Velson talked about carbohydrate polymers: polyvinyl acetate, polyvinyl alcohol, etc., in which solvent they dissolve (including water), how they age and how to reverse treatments. He emphasised the importance of not keeping materials beyond their shelf life, and of testing substances – every single time – before using them on the objects we are treating because, as we know, commercial products can be unpredictable due to storage conditions, changes in manufacturer specifications, etc.
Course participants testing adhesives in the Tate Britain Conservation Studio (photo courtesy of Yunsun Choi)
In the afternoon we moved to the Paper Conservation Studio, very kindly made available by the Tate Britain conservation staff, to go through seven practical activities organised by Velson for us to carry out in groups:
- Gloss measurement and colour change
- Starch solutions
- Testing the viscosity of solutions: ‘Falling ball’
- Testing the viscosity of solutions: ‘Rotating viscometer’
- Shrinkage on setting
- pH of liquid/solid material
- Strength of an adhesive
At the end of each activity, the groups presented their findings to the other course participants, explaining what was learnt from each activity, and how we can use those learnings in our day-to-day conservation practice. It was a very enjoyable and well-planned course, and I am glad I had the chance to attend it.
Stefania Signorello ACR, Conservator, The Wellcome Library
The Book & Paper Gathering 
Dear Stefania,
thank you for your interesting report. It could be possible to have a brief overview of the most important findings that the course participants pointed out about the different adhesives tested? Thank you,
Laura Dellapiana
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Hi Laura,
Thanks so much for your comment. Re the afternoon sessions, I have pages and pages of notes and it would not be easy to briefly summarise our findings. However, I can say that since the course I have been more prone to think that actually it doesn’t take long to measure the pH of an adhesive, using a pH pen as we did with Velson, and I think it should be done at least every time you open a new packet of the adhesive. I suppose that if you dilute your adhesive in water, you will also have to think about what water you are using, if tap water or deionised, as tap water is more likely to change. I was very surprised by the effect some of the adhesives had on the paper, pH-wise (we tested about 15 adhesives, and some of them changed istantly the pH of the paper). That reminded me that every time we add an adhesive to our objects we can potentially cause a sudden and localised increase or decrease of pH in areas we are treating, which are also already damaged and weak. One more thing I would like to do is to experiment with the different starches, at least the more common ones out of the existing thousands! Corn, tapioca, arrow root and rice can be easily found in supermarkets and would be good enough for experiments. It would be interesting to see how the different DPs and mechanical properties can be used to the conservator’ advantage.
Best wishes,
Stefania
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Dear Stefania,
thank you for your answer, it sounds really interesting! I would like to experiment different starches too… Hope to read soon a post about your findings, and to share our experiments… Good luck with your work
Laura
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