The Colour and Composition of Early Anglo-Saxon Copper Alloy Jewellery

500 Pages·2014·4.87 MB·English

by  J Baker

Durham E-Theses
The Colour and Composition of Early Anglo-Saxon
Copper Alloy Jewellery
BAKER, JOCELYN,MARGARET
How to cite:
BAKER, JOCELYN,MARGARET (2013) The Colour and Composition of Early Anglo-Saxon Copper
Alloy Jewellery, Durham theses, Durham University. Available at Durham E-Theses Online:
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The Colour and Composition of Early Anglo-Saxon
Copper Alloy Jewellery
Jocelyn Baker

ABSTRACT
Copper alloy artefacts are amongst the most prolific material remains from the early
Anglo-Saxon period (450-650 CE). This research attempts to circumvent the limitations
of previous disparate and unconnected typological and metallurgical approaches to
these objects by investigating copper alloy jewellery from a holistic interdisciplinary
approach. In particular, colour is used as a major new variable, a characteristic that
would have been relevant to the Anglo-Saxons as craftsmen and as consumers. This
method can reveal the choices that faced Anglo-Saxon craftsmen in the manufacture of
these objects and in the use of their materials according to variables relevant and
appropriate to their world.
All past quantitative composition data relating to this period are reanalysed
collectively, to interpret and model metal supply dynamics and recycling traditions. A
visual context for copper alloys is created using linguistic frequency analysis of Old
English colour words alongside a discussion of other Anglo-Saxon coloured material
culture. The application of quantitative colour measurement to archaeological material
and the factors affecting colour in various copper alloys on a structural level is also
delineated, including quantification of the limits of human colour distinction and
perception, the effects of tarnish on colour, and the overlap between copper and
precious metal colour space.
A new dataset comprising semi-quantitative ED-XRF composition data and quantitative
colour measurements from over two-hundred archaeological samples allows the
context of colour and composition to be discussed, providing insight into issues of
value, aesthetics, trade and metal supply, and control.

T C C
HE OLOUR AND OMPOSITION OF
E A -S
ARLY NGLO AXON
C A J
OPPER LLOY EWELLERY

JOCELYN MARGARET BAKER

Thesis submitted for the
Degree of Doctor of Philosophy
Department of Archaeology
University of Durham

2013

TABLE OF CONTENTS
The Colour and Composition of Early Anglo-Saxon Copper Alloy Jewellery ............ 3
List of Figures .............................................................................................................................................. 6
List of Tables ............................................................................................................................................. 16
Acknowledgements .............................................................................................................. 1
CHAPTER 1 Introduction ............................................................................................................. 3
Historical context .................................................................................................................. 4
Past Approaches to Anglo-Saxon Copper Alloys ....................................................... 7
Colour as a new variable .................................................................................................... 8
CHAPTER 2 Early Anglo-Saxon Copper Alloys ................................................................... 13
Introduction .............................................................................................................................................. 13
Copper Alloys ........................................................................................................................ 14
Metalworking Tradition ....................................................................................................................... 18
Roman Tradition ................................................................................................................. 18
Early Saxon Metalworking Evidence .............................................................................................. 25
Evidence from Early Saxon England ............................................................................ 25
Metal Ore Resources .......................................................................................................... 29
Recycling ................................................................................................................................ 34
Copper Alloy use in Early Medieval England............................................................................... 35
Past Composition Studies ................................................................................................ 35
Contemporary Continental Composition Studies ................................................... 51
Copper Alloy Use ..................................................................................................................................... 53
Migration Period Alloys Elsewhere ............................................................................. 55
Before and After .................................................................................................................. 57
Alloy component distribution ........................................................................................ 62
CHAPTER 3 Recycling of Copper Alloys in the Early Saxon Period ............................. 71
The Recycling of Copper Alloys......................................................................................................... 71
Roman Recycling Practices ............................................................................................. 72
The Appearance of Recycled Alloys ............................................................................. 74
Issues with Zinc-Rich Alloys ........................................................................................... 75
The Fresh Metal Supply .................................................................................................... 79
Control in Alloying in the Early Saxon Period .......................................................... 82
Modelling Copper Alloy Recycling ................................................................................................... 86
Source Alloys within the Recycling Model ................................................................ 92
Results ..................................................................................................................................... 97
1
CHAPTER 4 Colour in the Anglo-Saxon World ................................................................ 112
Introduction ............................................................................................................................................ 112
Colour Terms in Language ................................................................................................................ 114
Universal Development of Colour Terms ............................................................... 114
Prototype Theory ............................................................................................................. 116
Old English Colour Terms and Use ............................................................................ 118
Frequency of Colour Words in Old English ............................................................ 128
Summary .................................................................................................................................................. 135
High-Status Dress Fittings ................................................................................................................. 138
The Colour of Precious Metals .................................................................................... 138
The Use of Precious Metals in Dress Fittings ........................................................ 143
The Colour of Associated Enamels, Gems and Inlays ......................................... 146
Summary ............................................................................................................................. 151
Textiles ...................................................................................................................................................... 152
Material ................................................................................................................................ 153
Dyes ....................................................................................................................................... 154
Colour of Textiles ............................................................................................................. 156
Summary ............................................................................................................................. 157
Beads .......................................................................................................................................................... 159
Issues with Bead Colour Analysis .............................................................................. 159
Colourants Used in Early Medieval Beads .............................................................. 161
Frequency of Bead Colours .......................................................................................... 162
Chronological Colour Trends ....................................................................................... 164
Regional Patterns ............................................................................................................. 165
Trade Access ...................................................................................................................... 167
Comparison of Specific Sites ........................................................................................ 168
Conclusions ........................................................................................................................ 174
Pigments and their Use in the Early Medieval Period ........................................................... 175
Painted Walls and Sculpture ........................................................................................ 175
Manuscripts ........................................................................................................................ 178
Conclusions ........................................................................................................................ 181
Summary of Anglo-Saxon Colour ................................................................................................... 183
CHAPTER 5 Colour, Colourimetry and Human Colour Perception .......................... 186
Introduction ............................................................................................................................................ 186
Background to Colour .................................................................................................... 187
Qualitative Colour Measurement ................................................................................................... 188
Spectrophotometers ....................................................................................................... 188
SCI and SCE ......................................................................................................................... 190
Previous Related Research ........................................................................................... 191
Colour Measurement Systems .................................................................................... 192
Human Sensitivity and Colour Perception ................................................................................. 194
Calculating Colour Differences.................................................................................... 195
Colour Vision Experiment ............................................................................................. 198
Summary .................................................................................................................................................. 217
CHAPTER 6 Metal Structure, Colour and Tarnish ......................................................... 218
Introduction ............................................................................................................................................ 218
How colour is created in metal ................................................................................... 218
Characterisation of the Colours of Archaeologically Significant Copper Alloys ......... 224
Copper-Tin ............................................................................................................................................... 228
Copper-Zinc ............................................................................................................................................. 234
Copper-Tin-Zinc Alloys .................................................................................................. 238
Copper-Lead ....................................................................................................................... 242
Iron in Copper Alloys ...................................................................................................... 247
Other Elements and L*A*B* change .......................................................................... 250
Tarnish ...................................................................................................................................................... 252
Common Short-term Corrosion Products .............................................................. 252
Tarnish and Expected Appearance – Golden Metal? .......................................... 263
CHAPTER 7 Analytical Methods and Parameters .......................................................... 265
ED-XRF ...................................................................................................................................................... 265
Semi-Quantitative ED-XRF Parameters ................................................................... 266
Error ...................................................................................................................................... 267
Spectrophotometer .............................................................................................................................. 269
Development of Methodology ..................................................................................... 269
Minimum Analyses Test ................................................................................................ 270
Sample Preparation ......................................................................................................... 272
Sources of Error .................................................................................................................................... 274
Variation in a sample ...................................................................................................... 274
Working Procedure .............................................................................................................................. 276
CHAPTER 8 Results ................................................................................................................... 278
Introduction ............................................................................................................................................ 278
Broughton lodge .................................................................................................................................... 286
Discussion ........................................................................................................................... 288
Fonaby ....................................................................................................................................................... 290
Discussion ........................................................................................................................... 292
Castledyke South ................................................................................................................................... 295
Discussion ........................................................................................................................... 299
Cleatham ................................................................................................................................................... 302
Discussion ........................................................................................................................... 305
Sewerby .................................................................................................................................................... 308
Discussion ........................................................................................................................... 311
West Heslerton ...................................................................................................................................... 314
Discussion ........................................................................................................................... 321
Summary – Copper Alloys by Site .................................................................................................. 324
CHAPTER 9 Annular Brooch Typology .............................................................................. 328
Introduction ............................................................................................................................................ 328
Previous Typologies ............................................................................................................................ 328
Dating & Distribution .......................................................................................................................... 330
Type F ................................................................................................................................... 330
Type G ................................................................................................................................... 332
Summary .................................................................................................................................................. 336
CHAPTER 10 Discussion .......................................................................................................... 337
Introduction ............................................................................................................................................ 337
Copper Alloys in Early Medieval England ................................................................................... 339
Chronology .............................................................................................................................................. 341
Use of Alloying Components over Time .................................................................. 341
Alloy Types over Time ................................................................................................... 346
Composition and Colour by Artefact Type ................................................................................. 349
Brooches .............................................................................................................................. 352
Annular Brooches ............................................................................................................ 353
Quoit Brooches: Broad-band Annular Brooches or Mock-quoit .................... 358
Openwork Brooches ....................................................................................................... 362
Penannular brooches ...................................................................................................... 366
Great and Square-Headed Brooches ......................................................................... 367
Cruciform Brooches ........................................................................................................ 371
Small-Long Brooches ...................................................................................................... 377
Buckles ................................................................................................................................. 382
Girdle-hangers ................................................................................................................... 388
Wrist Clasps........................................................................................................................ 394
Appearance of Copper Alloys ........................................................................................................... 400
Expected Appearance ..................................................................................................... 400
Surface Coatings ............................................................................................................... 407
Unusual Alloys ................................................................................................................... 410
Object Pairs......................................................................................................................... 414
Assemblage Appearance ............................................................................................... 421
Summary ............................................................................................................................. 421
Chapter Summary ................................................................................................................................. 423
CHAPTER 11 Conclusions ....................................................................................................... 425
Colour ........................................................................................................................................................ 427
Copper .................................................................................................................................. 428
Lead ....................................................................................................................................... 428
Girdle-Hangers .................................................................................................................. 429
Brass ...................................................................................................................................... 429
Copper Alloys within an Anglo-Saxon Colour Context ...................................... 430
The appearance of gold .................................................................................................. 431
Patterns in Alloy Use ........................................................................................................................... 432
Recycling and Metal Supply .............................................................................................................. 434
Future Research .................................................................................................................................... 436
Bibliography................................................................................................................................ 439
Appendix A The Recycling Model ........................................................................................ 455
Appendix B Recycling Recipes .............................................................................................. 469
Appendix C Annular Brooch Typology............................................................................... 474

Appendix D on CD-ROM:
The Recycling Model
Modelled Results and Recipes

Database of Anglo-Saxon copper alloy compositions