Collections Demography - On Dynamic Evolution of Populations of Objects

The ‘Collections Demography’ project (2010–13) was one of the first research projects that brought together value assessment processes with modelling of degradation.

Background

Large heritage collections are managed in the context of four aspects and informed decisions are possible if evidence is available. The four aspects are:

• collection use.
• material properties.
• environmental considerations.
• resource requirements.

Aims and outcome

The Collections Demography project developed the terminology and the tools that are required to develop and visualise such evidence. It addressed large collections using principles of demography – collection items are accessed due to their value and used, they degrade and may become unfit with time. The key elements in the development of the model were:

• how the objects are valued and by who,
• how the impact of internal and external agents can be mathematically modelled, and
• at what point an object might be considered unfit for use (which could require a resource-intensive conservation intervention).

Findings

Findings in the Collections Demography project included:

• The role of stakeholders (e.g., the public, curators, researchers) in determining when an item is no longer fit for use.
• The modeling of paper degradation, with findings showing how material properties like the degree of polymerization (DP) affect wear and tear over time.
• The creation of tools like "isochrones," which predict when items will reach a threshold of unfit-for-use, depending on environmental conditions and conservation strategies.

The project also explored visitor perceptions of damage, finding that readers are more concerned about missing text than discolouration or minor physical wear. It showed that for objects with high-quality paper (DP > 800), degradation is minimal over 500 years, while acidic papers degrade much faster.

The research allowed for more informed, evidence-based decisions in managing heritage collections, balancing access, conservation, and resource allocation. The project also highlighted the importance of engaging stakeholders to ensure transparent and accountable decision-making in collection care.

For further details about the Collections Demography project you can explore the publications below.

Publications

Press release: Model predicts 'shelf life' for library and archival collections

Matija Strlič, Carlota M. Grossi, Catherine Dillon, Nancy Bell, Kalliopi Fouseki, Peter Brimblecombe, Eva Menart, Kostas Ntanos, William Lindsay, David Thickett, Fenella France & Gerrit De Bruin (2015) ‘Damage function for historic paper. Part III: Isochrones and demography of collections’, Heritage Science volume 3, Article number: 40

Matija Strlič, Carlota M. Grossi, Catherine Dillon, Nancy Bell, Kalliopi Fouseki, Peter Brimblecombe, Eva Menart, Kostas Ntanos, William Lindsay, David Thickett, Fenella France & Gerrit De Bruin (2015) ‘Damage function for historic paper. Part II: Wear and tear’, Heritage Science volume 3, Article number: 36

Matija Strlič, Carlota M. Grossi, Catherine Dillon, Nancy Bell, Kalliopi Fouseki, Peter Brimblecombe, Eva Menart, Kostas Ntanos, William Lindsay, David Thickett, Fenella France & Gerrit De Bruin (2015) ‘Damage function for historic paper. Part I: Fitness for use’, Heritage Science volume 3, Article number: 33

People

Dr Catherine Dillon
Researcher

Ann Fenech 
Researcher

Kalliopi Fouseki
UCL Institute for Sustainable Heritage
Co-Investigator

Dr Carlota Grossi
Researcher

Matija Strlic
UCL Institute for Sustainable Heritage
Principal Investigator

Eva Menart
Researcher 

Jinghao Xue
UCL Department of Statistical Science
Co-Investigator

Acknowledgements

The project wouldn’t have been possible without the generous support and help from:

• British Library: Fiona McCarthy
• City Binders: David Stevens
• English Heritage: Richard Askew, Madeleine Hawkins, Tina Hornsby, Robin Matthews, Caroline Rawson, Richard Smith-Gore 
• Library of Congress: Cindy Connelly Ryan, Meghan Hill, Matthew Kullman, Ray Privott, Mark Sweeney, Dianne van der Reyden, Hans Wang
• Manchester Museum: Nick Merriman
• Nationaal Archief: Gabriëlle Beentjes, Rene Gardien, Roberto Padoan 
• The National Archives: Hannah Clare, Dinah Eastop, Richard Williams
• University College London: Tiphaine Bardon, Matthew Chipping, Carolien Coon, Katherine Curran, Josep Grau, Andrej Kos, Pakhee Kumar, Julia Martinez, Keith Razey, Jane Robb 
• University of Leicester: Lisanne Gibson
• University of Strathclyde: Lorraine Gibson, Gemma Mitchell
• Wellcome Library: Gillian Boal, Sharon Messenger, Stefania Signorello

As well as 874 volunteers.

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Funding

This project was funded by Arts and Humanities Research Council (AHRC) along with financial support from EPSRC Science and Heritage Programme and Nationaal Archief.

Image credit

Unsplash: Erol Ahmed

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