By Jing Han, PhD student.
In ancient China, colour, pattern and material were all important symbols for rank, standing and for the hierarchical sequence of the society. In the court, the colour of one’s robe was, at a glance, enough to learn the grade of the royal family member or the official.
Behind this rigorous colour-coding system, there is a practical question: How were these colours achieved, and why?
In my doctoral research I dive into this mysterious world of dyeing, with the help of my supervisors, Dr Anita Quye from Textile Conservation and Prof Nick Pearce from History of Art.
Research of historical dye recipes
The starting point for my research was four historical manuscripts of the Ming and Qing Dynasties which record dye recipes. Two of them were written for general use, and two were written by experts in the field for professional use. I began by sorting out what dyes and dyeing methods were recorded. As I got further, my questions became more critical:
What specific kind/kinds of plants did the historical dye names refer to? What dyes were commonly used at that time? Why were certain dyes replaced? What is the difference between dye recipes at different times? Does the difference give a clue to how dyeing advanced during this period of time?
For some of these questions, I managed to find answers, and some I cannot answer yet. These questions lead me gradually to explore these dye recipes more and more in-depth and get unexpected and amazing results. Sometimes I feel that with certain questions research has a momentum of its own similar to a novel when the author does nothing else to develop stories but set a context and let the characters unfold.
Research on historical dyes
Manuscripts are only one side of the doctoral coin, the other side being how closely theoretical procedure is aligned with practical use.
To answer this question, I am investigating dyes of the Ming and Qing Dynasties by chemical analysis. In this aspect, I gratefully appreciate the support I have received from museums and private collectors in both the UK and China, enabling me to collect dye samples of various colour shades from provenanced costumes and textiles belonging to the imperial family and officials of different ranks.
This side of the research is even more exciting: Can I find from historic textiles tricks for dyeing not recorded in manuscripts? Can the questions not answered by literature research, such as the geographical difference in dyeing, be answered by the investigation of real materials? Did ideas of colour and dyeing interact? Again, there are so many questions in my mind.
Sampling from the back of a multi-coloured dragon badge with yellow background (early Kangxi period 1670-1680)© private collector
The answers are to be found within the very specific chemical structure of the dye molecule which usually contains a conjugated system formed by alternating single and multiple bonds. This conjugated system absorbs certain ranges of light therefore showing specific colours. Different dye sources contain different types of dye molecules, enabling us to predict their dye sources.
Examples of dye molecules: gallic acid (from gallnut), berberine (from Amur cork tree) and quercetin (from pagoda bud) © JH
The chemical method I use is Ultra Performance Liquid Chromatography with Photo Diode Array detection (UPLC-PDA) and UPLC-PDA-mass spectrometry (MS). By these methods, we are able to get much information on dyes from a very short length of thread end (approximately 0.5-1cm). In the analysis, different dye constituents are separated and identified by their retention time, UV-vis spectra and molecular ion weight. An example for differentiating the three main dye constituents of turmeric by UPLC-PDA-MS is presented below.
Ever since I began this doctoral research, I have been asked why I am undertaking research of a Chinese subject here in Glasgow. Well, as you see, with rigorous but free academic ambience and most supportive and kind colleagues, this is an ideal place for me to carry out this exciting research.
Papers in preparation
- Han, A. Quye. Dyes and Dyeing in the Ming and Qing Dynasties (1368-1911) in China: Preliminary Evidence Based on Primary Chinese Documentary Sources. Submitted to Textile History.
- Han. Botanical Provenance Research of Historical Chinese Dye Plants. Submitted to Economic Botany.