Argyronomicon, Silver Photographs on Paper, Alternative Photographic Processes

273 Pages·2019·47.398 MB·English

by  Mike Ware

Argyronomicon

Silver Photographs on Paper:
Chemical History of their Invention,
Deterioration, and Conservation
incorporating

The Sensitivity to Light of Talbot’s Halide-fixed Images
1834-1844

Mike Ware
MA DPHIL CCHEM FRSC
Honorary Fellow in Chemistry, University of Manchester, UK
Scientific Advisor to the National Gallery of Art, Washington DC
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Table of Contents
Preface ................................................................................................................................... 8
Acknowledgements...................................................................................................... 10
Section I Essays on Pre- and Proto-Photography ..................................... 11
1 Luminescence and Photography .................................................................. 12
1.1 Types of Luminescence ........................................................... 13
1.2 Early Phosphori ....................................................................... 14
1.3 Schulze’s Serendipitous ‘Scotophorus’ .................................... 17
1.4 Light, Dark, and Alchemy ........................................................ 17
1.5 Ontology of the Negative ........................................................ 19
1.6 Ambivalent Daguerreotypes .................................................... 20
1.7 Negative Inhibitions ................................................................ 22
1.8 Negative-Positive Processes .................................................... 23
2 Proto-Photographic Substances .................................................................. 28
2.1 Silver Salts .............................................................................. 28
2.2 Iron Compounds ..................................................................... 29
2.3 Salts of Other Metals ............................................................... 30
2.4 Dichromated Colloids.............................................................. 31
2.5 Sulphur ................................................................................... 33
2.6 Bitumen .................................................................................. 35
2.7 Resins..................................................................................... 36
2.8 Plant Matter ............................................................................ 36
2.9 Animal Matter ......................................................................... 38
2.10 Molluscan Dyes ..................................................................... 41
3 Invention of Photography ............................................................................... 44
3.1 The ‘Gernsheim Question’ ....................................................... 44
3.2 Proto-photography ................................................................. 44
3.3 Photographic Sensitivity .......................................................... 45
3.4 Sunlight .................................................................................. 46
3.5 Contact Prints and Photograms ............................................... 47
3.6 Development of the Lens ........................................................ 48
3.7 Criteria for Camera Photography ............................................. 49
3.8 Historical Proto-photographs .................................................. 51
3.9 Niépce in England 1827 .......................................................... 52
3.10 Sindonography ...................................................................... 54
4 Optics of Shadows ............................................................................................... 59
4.1 Skiology or Sciagraphy ............................................................ 59
4.2 Angular measure .................................................................... 60
4.3 The Eye's Resolution ............................................................... 60
4.4 The Sun's Aspect ..................................................................... 60
4.5 The Sky's Luminance ............................................................... 61
4.6 Sharpness of Shadows ............................................................. 62
4.7 Duration of Exposure .............................................................. 63
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4.8 Laws of Skiology ..................................................................... 64
4.9 Photograms ............................................................................ 67
5. Herschel’s Photographic Prints from Engravings ............................... 72
5.1 Exposure Duration in Early Photography .................................. 72
5.2 Sciagraphs or Photogenic Drawings ......................................... 72
5.3 Herschel's Versions of Photography ......................................... 73
5.4 Herschel’s Use of Engravings................................................... 74
5.5 Identification of the Engravings ............................................... 77
5.6 Literary Annuals and Gift-books .............................................. 80
5.7 The Evanescent Anthotype ...................................................... 83
5.8 Invention of Siderotype ........................................................... 83
5.9 Herschel’s Photo-etymology ................................................... 86
5.10 Siderotype Processes.............................................................. 86
5.11 The Exasperating Kelainotype ................................................ 88
5.12 A Neologism: the Diaphane .................................................... 89
Section II History of Silver Photography on Paper .................................... 90
6 Talbot's Achievements and Legacy ............................................................ 91
6.1 Invention of Photogenic Drawing ............................................. 91
6.2 Development of the Calotype .................................................. 95
6.3 Collections of Talbot's Photographs ........................................ 96
6.4 Correspondence...................................................................... 98
6.5 Catalogue Raisonné ................................................................ 98
6.6 Publications ............................................................................ 99
6.7 Patents ................................................................................. 101
6.8 Talbot’s Contemporaries in Photography ............................... 101
6.9 Texts on Photographic Chemistry .......................................... 102
7 Talbot's Materials and Modus Operandi ...............................................103
7.1 Classification and Nomenclature ........................................... 103
7.2 Silver Print-out Processes...................................................... 107
7.3 Photogenic Drawing Paper..................................................... 108
7.4 Ammonio-Nitrate of Silver Paper ........................................... 109
7.5 Fixation: Chemistry and Etymology ....................................... 110
7.6 Waterloo Paper...................................................................... 116
7.7 Leucotype Paper.................................................................... 116
7.8 Calotype Paper ...................................................................... 117
7.9 Albumenised and Waxed Papers ............................................ 120
8 Chronology of Talbot’s Developments ...................................................122
9 Properties of Early Silver Images ..............................................................125
9.1 Exposure Considerations....................................................... 125
9.2 Reciprocity Law and its Failure .............................................. 125
9.3 Coating Weight and Particle Size ........................................... 127
9.4 Colours of Talbot’s Prints ...................................................... 128
9.5 Old Hypo Colouring Baths ..................................................... 129
9.6 Sparling’s Iron Toner............................................................. 130
9.7 Gold Toning .......................................................................... 130
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10 Photography in Scotland 1842-1846 ....................................................133
10.1 Innovations at Saint Andrews .............................................. 133
10.2 David Octavius Hill and Robert Adamson ............................. 136
10.3 Robert Adamson’s Salted Paper Prints ................................. 137
10.4 William Holland Furlong ...................................................... 137
10.5 George Smith Cundell ......................................................... 138
11 French Calotypists 1847-1852 ...............................................................141
11.1 Louis-Désiré Blanquart-Evrard ............................................ 141
11.2 Dr A. Guillot-Saguez ........................................................... 143
11.3 Gustave Le Gray .................................................................. 144
11.4 Arsene Pelegry’s Process ..................................................... 145
12 British Photographic Practices in the 1850s ......................................148
12.1 Roger Fenton ...................................................................... 148
12.2 Calotype Variations ............................................................. 148
12.3 Societies and Journals ......................................................... 149
12.4 Photographic Materials Suppliers ......................................... 150
12.5 Pre-waxed Paper: John Percy ............................................... 150
13 Developments in Europe ..............................................................................152
13.1 Frédéric Flacheron and the Rome Circle ............................... 152
13.2 John Stewart in the Pyrenees ............................................... 153
14 Photography in India 1855-1870............................................................154
14.1 Photography in the Tropics ................................................. 154
14.2 Paper: the Negative Substrate of Choice .............................. 154
14.3 Tropical Cameras ................................................................ 155
14.4 Calotyping in India .............................................................. 155
14.5 Jesse Mitchell’s Procedure ................................................... 156
14.6 Alexander Greenlaw ............................................................ 157
14.7 The Legacy of Greenlaw's Process ........................................ 158
15 Summary of Calotype Variations ............................................................161
Section III Deterioration and Conservation of Silver Photographs .165
16 Light Sensitivity of Photogenic Drawings ...........................................166
16.1 Threshold of Perceptibility .................................................. 166
16.2 Threshold Exposure ............................................................ 167
16.3 Protection by Ultraviolet Filtration ....................................... 170
16.4 Becquerel Effect .................................................................. 171
16.5 Implications for Conservation .............................................. 171
17 Case Histories ...................................................................................................173
17.1 Identification of Processes ................................................... 173
17.2 Photogenic Drawings by Talbot ........................................... 174
17.3 Deterioration by Environment .............................................. 175
17.4 Salted Paper Prints .............................................................. 176
17.5 Albumen Prints ................................................................... 176
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18 Experiments on Simulacra ...........................................................................178
18.1 Previous Work ..................................................................... 178
18.2 Time-resolved Densitometry ............................................... 178
18.3 Results ............................................................................... 178
18.4 High Intensity Reciprocity Failure ........................................ 179
18.5 Evaluating the Threshold Exposure ...................................... 179
18.6 Demonstrating the Becquerel Effect ..................................... 179
18.7 Thiosulphate-fixed paper ................................................... 179
18.8 Conclusions ........................................................................ 180
19 Feasibility of Interactive Testing .............................................................181
19.1 The Ethical Dilemma ........................................................... 181
19.2 Tolerable Damage ............................................................... 182
19.3 Sampling and Image Granularity .......................................... 182
19.4 Time-resolved Microdensitometry ....................................... 182
19.5 Microfadeometry ................................................................. 183
19.6 Microfader testing of Talbot prints ...................................... 184
20 Conservation Issues .......................................................................................186
20.1 Minimising Exposure to Light on Exhibition ......................... 186
20.2 Dangers of Densitometry .................................................... 188
20.3 Photographing Light-Sensitive Objects ................................ 189
20.4 Illumination of Light-Sensitive Photographs ........................ 190
20.5 Review of Light Sources....................................................... 191
20.6 Risk Assessment of Illumination .......................................... 192
20.7 Examples of Potential Damage by Copying Lights ................ 198
20.8 Light Exposure by Photo-flash ............................................ 199
20.9 The Collection Environment ................................................ 201
20.10 Wrapping Materials and Enclosures .................................... 201
Section IV Photochemical Appendices ...........................................................204
21 Proto-photographic Sensitivity ...............................................................205
21.1 Coating Weight, Covering Power and Photometric Equivalent 205
21.2 Nutting Density Equation .................................................... 205
21.3 Extinction Coefficients of Photolytic Silver ........................... 206
21.4 Grain Size and Uncertainty in Density Measurement ............. 207
21.5 Calculation of Exposure Times ............................................ 208
21.6 Quantum Yields from Silver Halide Photolysis ...................... 209
21.7 Evaluation of the Threshold Exposure .................................. 210
21.8 Jones-Condit Equation ........................................................ 211
22 Colours of Silver Images .............................................................................212
22.1 Surface Plasma Resonance Absorption ................................. 212
22.2 Size and Colour of Nanoparticle Silver ................................. 212
22.3 Refractive Index of the Environment .................................... 213
22.4 Re-fixing Photogenic Drawings ........................................... 213
22.5 Effect of Aggregation .......................................................... 213
22.6 Effects of Surface Adsorption .............................................. 213
22.7 Problem of Photolytic Silver ................................................. 214
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22.8 Effect of Ammonia .............................................................. 215
22.9 Effect of Sulphiding on the Colour of Silver .......................... 215
23 Chemical Models for Silver Photography ...........................................216
23.1 Explanation of the Phenomena ............................................ 216
23.2 Photolytic Silver .................................................................. 216
23.3 Significance of Halogen Acceptors ....................................... 216
23.4 Impurity Adsorption onto Silver Halide Crystals ................... 217
23.5 ‘Sensitized’ Silver Halide ..................................................... 217
23.6 ‘Fixed’ Silver Halide............................................................. 219
23.7 Back-reactions Destroying Print-out Silver .......................... 220
23.8 Significance of Redox Potentials .......................................... 221
23.9 Fading of Iodide-fixed Prints ............................................... 221
23.10 Sulphiding of Silver Images ................................................ 222
23.11 Gurney-Mott Model of the Latent Image ............................. 223
Notes & References ....................................................................................................225

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For Marie
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Preface
This is a compilation of my various writings on early silver-based
photography which have been published over the last twenty-five years.
The essays within divide themselves naturally into four distinct categories
that define the sections of this book: pre-history, history, conservation,
and photochemistry. They need not be read sequentially, but dipped into
as a source of reference and – occasionally perhaps - amusement. How
the various components of this work came about entails an indulgence
into a brief personal history.
In 1992, the year that I took early retirement from my chemistry
lectureship at Manchester University, the National Museum of
Photography, Film & Television1 in Bradford, Yorkshire, England,
commissioned me to investigate the sensitivity to light of the earliest
photographs on paper in their collection, including the celebrated "first
negative" by William Henry Fox Talbot, dated 1835. This investigation was
prompted by a curatorial desire to put on public exhibition some of the
finest examples of early photographs in our national heritage. These
pictures, made by Talbot and his circle during the first decade of
photography, had never been exhibited before, so an essential early stage
of the planning required the definition of a suitable display environment
that would completely safeguard these unique items. However, my
ensuing study finally arrived at the conclusion that no such environment
could be defined for many of these objects, especially those that had only
been "fixed" by halides rather than by thiosulphate (“hypo”). My research
adopted a three-pronged attack: by theoretical calculations, destructive
testing of simulacra, and case histories of authentic specimens; all three
approaches indicated that even the most stringently controlled gallery
illumination was likely to cause measurable changes in halide-fixed silver
images within an unacceptably short duration of exposure. Planning for
the proposed exhibition was therefore -with regret- discontinued.
This unwelcome conclusion was originally embodied in a research
report that I compiled in 1993 for the curators of this historical material;
but they thought it appropriate at the time to open it to a wider
readership. Consequently, the evidence for the vulnerability of this
material became the subject of a small book entitled Mechanisms of
Image Deterioration in Early Photographs, published in 1994 by the
Science Museum, and the National Museum of Photography, Film &
Television. My original remit was broadened to satisfy three intentions:
first, to provide a caveat for curators elsewhere who hold examples of
such early photographic images in their collections; second, to provide an
account of the chemical science underpinning the study, and to expose it
to professional criticism and informed debate by museum scientists and
conservators; and third, by introducing quantitative concepts of ‘damage’
to such photographs, to assist curators in their ethical decision-making
when confronted by the conflicting obligations of their profession: both
to preserve such precious objects, and to make them accessible to
scholars and the general public, whenevever possible.
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The entire content of this 1994 publication - now long out of print - is
incorporated here in Sections II and III of this text, but it has been
extensively restructured, with a number of later additions and
emendations, in the light of feedback from many colleagues. Section II
outlines the technical history and modus operandi of the inventions by
Talbot and his peers, and of their subsequent inheritors; Section III is
concerned with the causes of deterioration in early silver prints, and with
procedures for their conservation. As its title states, this book is confined
to silver halide photosensitizers on paper; it does not extend to silver
photographic processes on surfaces of metal or glass, such as the
daguerreotype, ambrotype, or collodion wet-plate processes.
Although the scientific study of Talbot’s early photographs would
seem to arrive at a dishearteningly negative conclusion regarding their
safe exhibition, it does offer a positive compensation: that a modern
physico-chemical re-evaluation of these earliest photographic processes
on paper can make a useful contribution to our appreciation and
connoisseurship of the technical history and aesthetics of the medium.
Subsequent to this initial historical research, it was sugggested that
some further investigation of early photography from a scientific view-
point might throw more useful light on its pre-history; these studies were
eventually published in the academic journal History of Photography, over
the period 1997-2006. The content of these essays on pre- and proto-
photography forms the introductory Section I of this text, but the original
writings have been extended and updated here; they are not an essential
precursor to the rest, and are too diverse to be confined entirely to silver.
Although this work on early photographs is rooted in chemical
science, I hope that it will not be found unpalatable by readers with
backgrounds in the humanities, whence the custodians and scholars of
such material are mainly drawn. In the interests of not alienating the
humane reader, I have tried to banish most of the more recondite
chemical jargon to the appendices contained in Section IV of this book,
which carries more technical accounts of the photochemistry and
photophysics of silver images, wherein the scientifically inclined reader
may find the quantitative arguments and background references to the
chemical literature. The mechanistic interpretations put forward in these
Appendices can make no claims to authority or completeness; but I hope
that, by re-awakening this dormant aspect of early photographic science,
they may stimulate others to further it and correct my shortcomings.
The greatest reward for me on this personal journey has been the
discovery that scientist and humanist can still communicate with one
another today through a mutual interest and delight in the creative work
of the 19th century polymaths who were supreme exponents of both
disciplines. To epitomise photography as a meeting ground for such
scholarship, I can do no better than quote the words of Henry Talbot
himself: ‘...I feel confident that such an alliance of science and art will
prove conducive to the improvement of both.’
Mike Ware, Buxton, 2017

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Acknowledgements
In 1992, the Senior Curator at the National Museum of Photography, Film
& Television, Dr. Roger Taylor, became responsible for setting my feet on
this fascinating path; I could not have travelled any significant distance
along it without his unstinting help and encouragement throughout the
ensuing twenty-five years. He was also my co-author of a paper on the
history of the calotype process which forms the basis for §10, §11, & §12
of this text.2
The eminent photohistorian Professor Larry J. Schaaf, presently
Director of the Talbot archive at the Bodleian Libraries, Oxford, and
author of the Talbot catalogue raisonné, has been a source of much
wisdom and scholarship throughout the last quarter-century, and his
perceptive criticisms of my draft report initially helped to sharpen my
arguments; he also greatly eased my task by generously making available
his transcripts of Talbot’s Notebooks P and Q , at an early stage before
their publication.
In 1993 at Kodak UK Ltd., Drs. Hilary Graves, Chris Graebe, Trevor
Tucker, Arthur Saunders, Chris Roberts, and their colleagues, were most
generous in providing their expertise in photometrology, and in allowing
me access to their instrumentation for experimental measurements.
I am also indebted to Dr Boris Pretzel of the Victoria and Albert
Museum, and Dr David Saunders of the National Gallery, London, for their
expert knowledge of the physics of museum illumination and for much
helpful advice and comment. The cooperation of Scott Geffert, previously
of the Center for Digital Imaging Inc., New York, and now of the
Photography Studio of the Metropolitan Museum of Art, New York, is also
warmly acknowledged.
I thank the National Galleries of Scotland for financial support of the
part of this project relating to Scottish photography. I am indebted to Dr
Sara Stevenson, formerly of the Scottish National Portrait Gallery, and to
Dr Alison Morrison-Low of the National Museums of Scotland for
generously sharing their expert knowledge of the Hill and Adamson
archives. I am also grateful to Drs. Katherine Eremin, James Tate, and
James Berry for communicating their analytical findings and for valuable
discussions.
Any study of the chemistry of historic photographic processes will
soon bring one into touch with the professionals of photograph
conservation, so I should like to record my particular indebtedness to my
mentors, colleagues, and friends of the Photographic Materials Group of
the American Institute for Conservation of Historic and Artistic Works:
Lisa Barro, Brenda Bernier, Lee Ann Daffner, Dana Hemmenway, Norah
Kennedy, Adrienne Lundgren, Constance McCabe, Andrew Robb, and
Sarah Wagner. Several curators of historic photographs have been
generous in making accessible the precious objects in their various
treasure-houses: John Benjafield, Michael Gray, Colin Harding, Mark
Haworth-Booth, the late Peter James, Brian Liddy, Russell Roberts, Sara
Stevenson, Roger Watson, and Philippa Wright.
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