For over 20 years, Professor Alison Hulme has collaborated with partners in heritage institutions in the UK and worldwide to bring cutting-edge analytical chemistry insight to the study of historic dyes, enhancing the conservation and interpretation of valuable artefacts.
Challenges in historic dye analysis
The analysis of natural product dyestuffs poses major challenges due to the difficulties of sampling, the wide range of potential species used as dyestuffs, closely overlapping dye component profiles for different species, and the variation in degradation of the dyestuffs due to storage and display conditions over time. Techniques are needed which avoid or minimise destruction through sampling – crucial when dealing with valuable historic artefacts – and accurately identify dyestuff source to enable correct historical interpretation and appropriate conservation.
Advanced chemical analysis of historic dyestuffs
The Hulme group’s work has provided cutting-edge analytical chemistry insight for heritage sector partners worldwide, and established analysis techniques and reference data for dye origins which are now used across the sector. Early work pioneered the use of modern mass spectrometry techniques for the analysis of natural product dyestuffs, with a particular focus on light-fugitive, yellow flavonoid dyes which had posed a particular problem in heritage analysis. Subsequent work introduced Ultra High Performance Liquid Chromatography to the field, with the corresponding advantages of smaller sample sizes, vastly improved separation and analysis capability, increased sensitivity and faster analysis times allowing a more statistical analysis of material collections than was previously possible.
Right: Genista Tinctora. Attribution: Carl Axel Magnus Lindman, Public domain, via Wikimedia Commons
Enhanced conservation and interpretation of historic artefacts
The group’s work has analysed complex samples from a wide range of important historical pieces to provide insight into their provenance (e.g. dating and trade routes associated with their production), and to inform object display conditions and rotation criteria to minimise the impact on particularly light-sensitive artefacts. Major projects for the group have included:
- The first ever analysis of tapestries from English (Hampton Court Palace), Spanish (Palaçio Real de Madrid), and Belgian royal collections, informing their continued display and analysis;
- The first analysis of the dyes used to create the early English tapestries in the Burrell Collection’s world-leading collection, preparing them for cataloguing and conservation;
- Analysis of key pieces from National Museum Scotland’s textile collection in preparation for the opening of the new Fashion and Style gallery, helping conservators to identify the optimum display schedule and conditions for pieces in the gallery – and uncovering early examples of both Perkin’s and Caro's Mauve, the first patented synthetic dyes to produce this previously rare colour, which was a fashion sensation in the mid-1800s;
- Determination of the dyestuffs and unusual manufacturing processes used to create rare North Athapaskan quillwork artefacts, making use of non-invasive and microsampling techniques to analyse the thin layer of colour on these delicate objects. The discovery that a mixture of semi-synthetic and natural dyes had been used – from both European and American sources – completely changed the story of these artefacts’ provenance.
Above: Detail from one of the Burrell Collection’s “Sheldon” tapestries (late C16th England), with pink colour found to be from extremely light-sensitive safflower dye. This work is licenced under a Creative Commons Attribution-NonCommercial 4.0 International License.
A Royal Society of Chemistry technical brief co-authored by Professor Hulme and National Museum Scotland Analytical Scientist Dr Lore Troalen presents a comprehensive guide to the principal analytical methods used in dye and mordant analysis for users across the field. Former Hulme group PhD students have carried their expertise to roles at National Museums Scotland in Edinburgh, the National Gallery in London, and the Swiss Institute of Art in Zurich.
Find out more
- ‘Historical Textile Dyeing with Genista tinctoria L.: A Comprehensive Study by UPLC-MS/MS Analysis’: L. G. Troalen, A. S. Phillips, D. A. Peggie, P. E. Barran, A. N. Hulme, Anal. Methods, 2014, 6, 8915-8923.
- ‘A Multi-Analytical Approach Towards the Investigation of Subarctic Athapaskan Colouring of Quillwork and its Sensitivity to Photo-Degradation’: L. G. Troalen, S. Röhrs, T. Calligaro, C. Pacheco, S. Kunz, J. M. del Hoyo-Meléndez, A. N. Hulme, Microchem. J., 2016, 126, 83-91.
- ‘Historical mystery solved: A multi-analytical approach to the identification of a key marker for the historical use of brazilwood (Caesalpinia spp.) in paintings and textiles’: D. A. Peggie, J. Kirby, J. Poulin, W. Genuit, J. Romanuka, D. F. Wills, A. De Simone, A. N. Hulme, Anal. Methods, 2018, 10, 617-623.
- ‘Analysis of historical dyes in heritage objects’: Analytical Methods Committee Heritage Science Expert Working Group, Anal. Methods, 2021, 13, 558-562.