Want to know more about how we analyse pigments and paints?? We can use a large range of techniques for analyses all of which have their advantages and disadvantages. For example some are more suited to inorganic pigments such as minerals and their synthetic equivalents, whereas others are more appropriate for the analysis of organic chemicals. Observational techniques such as reflected light and polarising light microscopy enable differentiation of crystalline phases with the same chemistry, for example, synthetic chalk and mineral chalk. These techniques can also be used to analyse lake pigments and non-crystalline phases too. Many techniques used by analytical chemists are appropriate for pigment analyses. The majority of these are based on spectroscopy or mass spectrometry which detects elements and compounds based on their molecular structure and the behaviour of bonds between atoms (ions) in these phases. It is always good practice to use a range of techniques for the analysis of pigments. Some techniques complement each other and using several techniques can extend the range of information concerning, provenance, manufacturing and application of materials.  Listed here are a handful of publications (there are literally thousands out there in the scientific literature which tackle the analysis of artists’ pigments. The first section includes papers which introduce ‘classic’ techniques. The second section is a random selection of papers published in the last year or so which demonstrates the application of a range of techniques on a range of pigments and paints. Sadly, not all of the scientific literature is open access so some of you made need a institutional library subscription to access the full paper but always try googling the title in case its available via another platform. I’ve included DOI links where relevant. Also, not all books are available on line.

Some books and papers on materials in paints, colour and analytical techniques

Bell, I. M., Clark, R. J. H. & Gibbs, P. J., 1997, Raman spectroscopic library of natural and synthetic pigments (pre ~ 1850 AD)., Spectrochimica Acta Part A 53, 2 159-2179. https://www.sciencedirect.com/science/article/pii/S1386142597001406

Burgio, L. & Clark, R. J. H., 2001, Library of FT-Raman spectra of pigments, minerals, pigment media and varnishes, and supplement to existing library of Raman spectra of pigments with visible excitation., Spectrochimica Acta Part A 57, 1491–1521. https://www.sciencedirect.com/science/article/pii/S1386142500004959

Cardon, D., 2007, Natural dyes: sources, tradition, technology and science., Archetype ublications, London, 778 pp.

Chiari, G. & Scott, D. A., 2004, Pigment analysis: potentialities and problems., Special Issue 3: A showcase of the Italian research in applied petrology., Periodico di Mineralogia., 73, 227-237. https://www.researchgate.net/publication/242485634_Pigment_analysis_Potentialities_and_problems

Christie, R. M., 2015, Colour Chemistry: 2nd Edition., Royal Society of Chemistry, Cambridge, 345 pp.

Clark, R. J. H., 2002, Pigment identification by spectroscopic means: an arts/science interface., C. R. Chimie 5, 7–20. https://www.sciencedirect.com/science/article/pii/S1631074802013413

Dyer, J. & Sotiropoulou, S., 2017, A technical step forward in the integration of visible-induced luminescence imaging methods for the study of ancient polychromy., Heritage Science, 5, 24 https://heritagesciencejournal.springeropen.com/track/pdf/10.1186/s40494-017-0137-2.pdf

Dyer, J., Verri, G. & Cupitt, J., 2013, Multispectral Imaging in reflectance and photo induced luminescence modes: a users manual., The British Museum, London., https://www.researchgate.net/publication/267266175_Multispectral_Imaging_in_Reflectance_and_Photo-induced_Luminescence_modes_A_User_Manual

Eastaugh, N., Walsh, V., Chaplin, T., & Siddall, R., 2004, The Pigment Compendium: Optical Microscopy of Historical Pigments. Elsevier – Butterworth Heinemen., 416 pp.

Eastaugh, N., Walsh, V., Chaplin, T., & Siddall, R., 2008, Pigment Compendium: A Dictionary and Optical Microscopy of Historic Pigments. (1st ed.). London: Butterworth-Heinemann., 958 pp.

Kirsch, A. & Levenson, R. S., 2000, Seeing through paintings: physical examination in art historical studies., Yale University Press, New Haven & London., 328 pp.

Mayer, R., 1991, The Artists’ Handbook of Materials and Techniques: 5th Edition., Faber & Faber, 761 pp.

Osticioli, I., Mendes, N. F. C., Nevin, A., Gil, F. P. S. C., Becucci, M. & Castelluci, E., 2009, Analysis of natural and artificial ultramarine blue pigments using laser induced breakdown and pulsed Raman spectroscopy, statistical analysis and light microscopy., Spectrochimica Acta Part A 73, 525–531. https://www.sciencedirect.com/science/article/abs/pii/S1386142508006446

Scott, D. A., 2002, Copper and Bronze in Art: corrosion, colorants, conservation., Getty Publications, Los Angeles., 515 pp.

Siddall, R. 2018, Mineral Pigments in Archaeology: Their Analysis and the Range of Available Materials., Minerals, 8 (5), 201, 35 pp. https://doi.org/10.3390/min8050201

Spizzichino, V., Angelini, F., Caneve, L., Colao, F., Corrias, R & Ruggiero, L., 2015, In situ study of modern synthetic materials and pigments in contemporary paintings by laser-induced fluorescence scanning, Studies in Conservation, 60, sup1, S178 S184. https://www.tandfonline.com/doi/full/10.1179/0039363015Z.000000000222

Taylor, P., 2015, Condition: the aging of art., Paul Holberton Publishing, London, 263 pp.

Some recent papers which demonstrate state of the art technology applied to the analysis of paints from different periods and using different materials, including some modern paint analyses.

Aguilar-Rodríguez, P., Mejía-Gonzalez, A., Zetina, S., Colin-Molina, A., Rodríguez-Molina, B. & Esturau-Escofet, N., 2021, Unexpected behavior of commercial artists’ acrylic paints under UVA artificial aging., Microchemical Journal 160, 105743. https://doi.org/10.1016/j.microc.2020.105743

Berthold, C., Zimmer, K. B., Scharf, O., Koch-Brinkmann, U. & Bente, K., 2017, Nondestructive, optical and X-ray analytics with high local resolution on Attic white-ground lekythoi., Journal of Archaeological Science: Reports, 16, 513–520. https://doi.org/10.1016/j.jasrep.2016.02.008

Ceccarelli, S., Guarner, M., Romani, M., Giacopini, L., Francucci, M., Ciaffi, M., Ferri De Collibus, M., Puiu, A., Verona-Rinati, G-L., Colao, F. & Fantoni, R., 2021, Are the blue daemons really blue? Multidisciplinary study for the colours characterization of the mural paintings inside the Blue Daemons Etruscan tomb., Journal of Cultural Heritage 47, 257–264. https://doi.org/10.1016/j.culher.2020.09.002

Huntley, J., Wallis, L. A., Stephenson, B., Karlka Nyiyaparli Aboriginal Corporation & Davis, A., 2021, A multi-technique approach to contextualising painted rock art in the Central Pilbara of Western Australia: Integrating in-field and laboratory methods., Quaternary International 572, 52–73. https://doi.org/10.1016/j.quaint.2020.05.032

La Nasa, J., Campanella, B., Sabatini, F., Rava, A., Shank, W., Lucero-Gomez, P., De Luca, D., Legnaioli, S., Palleschi, V., Colombini, M-P., Degano, I. & Modugno, F., 2021, 60 years of street art: A comparative study of the artists’ materials through spectroscopic and mass spectrometric approaches., Journal of Cultural Heritage 48, 129–140. https://doi.org/10.1016/j.culher.2020.11.016

Pozzi, F., Basso, E., Centeno, S. A., Smieska, L. M., Shibayama, N, Berns, R., Fontanella, M. & Stringari, L., 2021., Altered identity: fleeting colors and obscured surfaces in Van Gogh’s Landscapes in Paris, Arles, and Saint‑Rémy., Heritage Science, 9:15. https://doi.org/10.1186/s40494-021-00489-1

Steger, S., Stege, H., Bretz, S., & Hahn, O., 2021, Disclosing glittering and sparkling effects in 20th-century reverse glass paintings: a study of metallic pigments and metal foils by means of in situ XRF and DRIFTS analysis., Journal of Cultural Heritage 48, 196–204. https://doi.org/10.1016/j.culher.2020.11.008

A Colour A Day: Week 52. 15-21 March 2021

Jo Volley writes…

The arrangement of this week’s colours is taken from Agnes Denes’ poem Colors of the Week* and features David Dobson’s 2017 invention Deep Water Blue pigment. David explains.

‘The colours of the common minerals are dominated by the presence of iron. Iron atoms in minerals take on two charges, loosing either two or three electrons to make ferrous (Fe2+) or ferric (Fe3+) iron. Iron oxides and hydroxides commonly contain mixed valence states and exchange of electrons between the ferric and ferrous states produces the reds and yellows seen in the earth pigments. In silicate minerals, such as olivine, iron replaces divalent magnesium and Fe2+ dominates. In this case electronic transitions localised on the iron ion causes olivine to have pale green colours. Very occasionally charge transfer between iron ions in ferric and ferrous states can cause blue colouration. Vivianite is an iron phosphate where the iron is in the 2+ state. When fresh it is colourless, however exposure to air causes some oxidation to iron 3+, some of which which sits on the tetrahedral phosphate site and a blue colour develops quite quickly. It seems that this tetrahedral ferric iron might be the key to making iron-based blues. Ringwoodite is a vibrant blue silicate spinel which is stable between 520 and 660 km depth in the Earth. In this case the colour only develops when there is a charge-coupled substitution of Fe3+,H+ onto the tetrahedral Si4+ site. This substitution is quite easy in ringwoodite, and if all of the Earth’s ringwoodite were fully hydrated it would contain something like 4 times the amount of water in the oceans. The Deep Water Blue pigment uses silicate and germanate structures which can take significant amounts of ferric iron on tetrahedral sites to reproduce the colour of ringwoodite.’

David Dobson is a geologist, mountaineer and print-maker. He is interested in process, whether that is the chain of action linking winter mountaineering to a final image or developing new pigments. He is also a professor at UCL, Earth Sciences and the first Slade Scientist in Residence 2018-19

Instagram:@m3m_works

YouTube: One Minute Geology

Image: Fe-Mg ringwoodite David Dobson

THE COLOR OF MONDAY IS WHITE
Lithopone
THE COLOR OF TUESDAY IS YELLOW
Turmeric
THE COLOR OF WEDNESDAY IS ORANGE
Persian Orange
THE COLOR OF THURSDAY IS GRAY
Grey Rose
THE COLOR OF FRIDAY IS BLUE
David Dobson’s Deep Water Blue
THE COLOR OF SATURDAY IS BROWN
Brown-Red Slate
THE COLOR OF SUNDAY IS RED
Cinnabar
IT HAS BEEN THAT WAY ALL MY LIFE.
*Thanks to Lesley Sharpe for directing me to this poem.

Today is both International Colour Day & World Poetry Day and the eve of World Pigment Day established in 2019 by Ruth Siddall and myself. This project started on 23rd March 2019 in an attempt to celebrate and document it’s initial year by simply dedicating a painted swatch of colour to each day and pure coincidence it was also the first day of lockdown in the UK but has somehow documented this most extraordinary year. It was inspired by A Boogert’s C17 educational manual of how to mix every colour available and influenced by Werner’s Nomenclature of Colours with Patrick Syme’s amendments. A Colour A Day is now finished (I hesitate to say complete as I haven’t painted every colour available to me in my studio) and later in the year they will be made into a series of digital prints and a publication.
Thank you to all of you who have sent me pigments and paints, writings and poems to include.

A Colour A Day: Week 49. 22nd – 28th February

Jo Volley writes…

This weeks colours are mainly produced by Ruth Siddall who says of them;

These slates and shales represent the Palaeozoic stratigraphy of north west England and Wales. The coal-black, black shale from Britannia Quarry in the Pennines and was collected during a field trip to the South Pennine Coalfied with Onya McCausland. The slates from Penrhyn (Cambrian Slate) and Blaenau Ffestiniog and the red shale from the shores of the Menai Straits were all collected in North Wales over the past year. I would like to dedicate this set of pigments to my late mother, Anne Siddall (8th June 1940-22nd November 2020) who grew up in Lancashire, the daughter of parents from North Wales and with ancestors who worked in the slate quarries of the region. The Plas Brereton red ochre slate outcrops close to her final home in Caernarfon.

All colours are bound in gum Arabic on Winsor & Newton watercolour paper and read from left to right.

Cambrian Heather Slate
Cambrian Sage Slate
Blaenau Grey Slate
Blaenau Ochre Slate
Plas Brereton Red
Britannia Black
Cote d’Azure Violet from Kremer Pigments

A Colour A Day; Week 48. 15-21 February

Jo Volley writes…

This week are colours are seven earths generously gifted to me by their makers and accompany George Szirtes’ wonderful poem Soil.

‘Soil takes place in England on a train journey. I was taking a ride I think from London up to Yorkshire and I looked out at the soil, the earth and I thought I recognise that colour – where does that colour come from? And what does it mean to me? It seemed to be saying something, it seemed to be saying something and it brought to my mind the subject of belonging – to the soil, or to that soil.’ George Szirtes

Soil

What colour would you call that? That brown
which is not precisely the colour of excrement
or suede?
The depth has you hooked. Has it a scent
of its own, a peculiar adhesiveness? Is it weighed,
borne down
by its own weight? It creeps under you skin
Like a landscape that’s a mood, or a thought
in mid-birth,
and suddenly a dull music has begun. You’re caught
by your heels in that grudging lyrical earth,
a violin
scraped and scratched, and there is nowhere to go
but home, which is nowhere to be found
and yet
is here, unlost, solid, the very ground
on which you stand
but cannot visit
or know.

From The Budapest File (Bloodaxe, 2000) George Szirtes 2000; used by permission of the owner. Click to listen to George reading Soil.

Colours read from top to bottom on W&N watercolour paper:

Christine Chua’s Singapore Ochre
Chalybeate – Cohen’s Fields Fountain JV/2020
Gail Lamarche’s Arizona Red
Penelope Kupfer’s Waterfall Red – Brazil 2019/20
Penelope Kupfer’s Roadside Red – Brazil 2019/20
Hampstead Heath no.6 JV/2020
Onya McCausland’s Six Bells Burnt Ochre (oil paint)

Chalybeate Fountain, Cohen’s Fields, Hampstead Heath

A Colour A Day: Week 47 8th – 14th February
Jo Volley writes…

This week’s colours accompany this beautiful poem by artist and poet Sharon Morris.

The purpose of blue

But it’s the colours I miss, don’t you see?
the lapis sky and fair cerulean blue
of ocean, the precise shivering hue
of your laugh on a bright day, so clear.

Whatever the light, lavender appears
to shave blue from grey, the way I knew you.
I’m dead-heading the daisy – though it’s futile –
sweeping leaves and weeding ‘volunteers’.

My eyes close – the way whales slip from view
between the waves – I have to let you go.
I still wear that specific shade of turquoise –

you looking out at the Pacific Ocean –
the way blue sky screens emptiness, its purpose
forgetting or holding on. Is this beauty?

The purpose of blue is from a set of sonnets, some of which were published in the anthology Tying the Song, Enitharmon Press, 2000. Sharon is also a Professor of Fine Art, Slade Deputy Director (Academic) and Head of the PhD Programme.

Colours read from left to right on W&N watercolour paper.
Methyl Violet pigment bound in gum Arabic
Cerulean Blue pigment bound in gum Arabic
Dumont’s Blue W&N watercolour
Vivianite pigment bound in gum Arabic
Oregon Blue (Yin mIn Blue), Derivan, Matisse Range*
Monastral Blue pigment bound in gum Arabic
Bronze Blue pigment bound in gum Arabic

*I first became aware of Yin MIn Blue in the summer of 2016 and wrote to the manufacturers requesting a sample for the Slade Material Research Project Pigment Collection but without luck. I then discovered a paint manufacturer in Australia, Derivan, were advertising it in their Matisse range as Oregon Blue and wrote a similar email asking for a donation. This is response from Steven Patterson, Derivan’s Chief Executive Officer that summer.
‘Thank you for your email – I would be happy to send you a sample of the paint we have made with the pigment, however we do not have any dry pigment left!!! we have used it all!!! – yet if you are happy with the paint please let me know the best address to send it to.’
I accepted his kind offer and very excited to receive a few weeks later two tubes plus some lovely colours from their Natural Pigments of Australia range which have been featured in previous weeks A Colour A Day.
A conversation in the Housman bar over the newly acquired blue with Ruth Siddall and David Dobson got David thinking about inventing his own new blue – more on that another time. At a later date Steven Patterson very generously sent a sample of the pigment, now part of the collection, and featured in an exhibition in the Material Museum during Colour & Poetry: A Symposium 2019.

A Colour A Day: Week 46. 1st – 7th February 2021

Jo Volley writes …

This week we celebrate seven orange pigments with an accompanying text written by Ed Winters.

Orange is both a direct and indirect reference to the secondary colour. It is direct in that it names the colour. It is indirect in that it refers to the citrus fruit which, when ripe, exemplifies the colour. It is a secondary colour in that it can be ‘divided by’ red and yellow, the two primary colours between which it sits on the colour wheel. It is the complementary colour of the third primary colour, blue. It is as warm as blue is cool.Thus, we can begin to build up descriptive relations between orange and the system of colours into which its place is uniquely specified in advance. If that sounds queer, it is because colour is, first and foremost, apprehended in and through perception. To talk of a colour geometry is to posit a system which is conceived a priori. If no-one had ever seen orange, say because there just happened to be no orange surfaces in the world, we would nevertheless feel that there is somewhere in colour space awaiting its arrival; a gap, so to speak. Given our conception of complementary colours we would be puzzled by the gap that is left in partnering blue with its complementary. (We would have to think of orange even if we had never seen it. And that is a very odd thought). It is a bright colour with a tonal value between the lighter colour yellow and the darker colour red. It thus reflects more light than its complementary blue (the so called “problem of inverted qualia”). Wittgenstein, in noticing such features of colours, undermines the thought that what you see as orange could be what I see as blue. Hence Wittgenstein looks to these other features of colour properties to begin to identify colours without recourse to indirect descriptions.

Dr Edward Winters is a writer and artist. He is an elected member of the Association Internationale des Critiques d’Art; and an elected member of the council of the Royal Institute of Philosophy. He writes widely on art and aesthetics.

All pigments are bound in gum Arabic on W&N watercolour paper and read:

First rectangle clockwise from top:

Orange Vermilion

Chrome Orange

Alizarin Orange

Monolite Orange

Second rectangle clockwise from top:

Lead Tin Orange

Lead Tin Orange

Iragazine Orange

End rectangle:

Mineral Orange

A Colour A Day: Week 45. 25 – 31 January

Jo Volley writes…

This week we have seven beautiful copper based pigments manufactured by Ruth Siddall who says of them:

‘Of this set of seven pigments, four are derived from natural mineral samples and three are synthetic. Two are made by reacting metallic copper with vinegar plus or minus salt to produce verdigris (copper acetate) and atacamite (copper hydroxy chloride). The final synthetic pigment is a precipitate of copper carbonate formed by mixing copper sulphate solution with sodium carbonate solution. The natural minerals were bought from reputable mineral dealers and were sourced from copper mines in the Katanga region of the Democratic Republic of Congo.‘

All pigments bound in gum Arabic on W&N watercolour paper and read from left to right:

Copper Carbonate
Malachite & Azurite
Malachite
Verdigris
Synthetic Atacamite
Azurite
Malachite & Chrysocolla

A Colour A Day: Week 44.  18th-24th January

Jo Volley writes…

This week’s colours were manufactured at Joshibi University of Art & Design,  Japan and donated to the Slade some 20 years ago, where they are now housed as part of the Slade Material Research Project Pigment Collection. 

At that time the Joshibi department were conducting a study on materials used in traditional Japanese painting adding to their understanding and knowledge outside of Japan.  Along with 14 pigment sachets of colours and glues, there are 5 very beautiful sample boards of 45 pigments including an explanation sheet to their origins and production. 

Here are my favourite seven pigments.

Each pigment is bound in animal skin glue on Winsor & Newton watercolour paper.

Top row from left to right:

Stones from Fuji River   

Sand (heat-treated) from the Sahara

Stones heat-treated) from Fuji River   

Middle row: Japanese glass beer bottles

Bottom row from left to right:

Soil from Joshibi

Mussel Shells

Sand from Mount Fuji

A Colour A Day: Week 42. 4-10 January

Jo Volley writes…

This week we have more earth pigments collected and manufactured by Ruth Siddall who says of them;

‘These are a series of British earth colours derived from some of the geological formations of southeast England. Ashdown Orange, Galley Hill Gold, Galley Hill Red and Road Works Red are all from the Cretaceous Wealden facies and all were collected in and around Bexhill in East Sussex. These strata expose terrestrial deposits which include fossil soils (palaeosols) as well as ochre-stained sandstones. The Road Works Red was procured from some kindly municipal workmen who were digging up the road outside St Mary Magdalene’s Church in Bexhill. River Ching and Walton-on-the-Naze clays are both derived primarily from the London Clay deposits of the London Basin. The River Ching flows through Higham’s Park in NE London, once a landscape garden laid out by Humphry Repton in the 1790s. The lake in the park is Repton’s construction, and the banks of the Ching which flows alongside the lake, are largely ‘made ground’ which mixes the London Clay with the overlying Ice Age Woodford Gravels. Here in NE London, the London Clay is dark grey and the clays from the Woodford Gravels is pale brown. At Walton-on-the-Naze, London Clay underlies a spectacular sequence of Ice Age strata. Again largely of continental origin, red beds dominate the sequence here. The red ochre from Stone Point, extracted from a thin horizon of red sandstones is possibly very recent in age and certainly Holocene. The pigments derived from these geological strata required a lot of processing, including washing, levigating, grinding and sieving to extract a suitable pigment.‘

All pigments are bound in gum Arabic on W&N watercolour paper and read from left to right:

Walton-on-the-Naze London Clay
Ashdown Orange
Galley Hill Red
Galley Hill Gold
Road Works Red
Stone Point Red Ochre
River Ching Ochre