TWO 
TWO People may have recognized the materials used in painting from other contexts, but did that influence the way they perceived paintings? The question cannot be answered by looking at contemporary commentaries on works of art for the simple reason that almost none exist. There are, however, some general statements suggesting that knowledge of materials could enhance the appreciation of art, such as St Bonaventure’s remark that ‘It is knowledge that makes the work beautiful.’1 The question can be answered by looking (with the help of some modern scientific equipment) at exactly how artists used their materials. This chapter proposes that painters and patrons chose materials for more than just the colours they gave. In other words, mysteries like lead white’s origins could indeed contribute meaning to paintings.
Chapter Two looks at how one artist used the powder of two different blue rocks in his paintings. The paintings are 42 large illuminations and 137 lavishly decorated initials spread across 140 folios of one of the most luxurious pontificals in existence. A pontifical outlines the duties of a bishop and this particular one was probably made in Metz, northeastern France. It was commissioned by Renaud de Bar, Bishop of Metz, and his mother in 1303 but was never finished. Work almost certainly stopped when Renaud died in 1316, possibly poisoned by political enemies. As such, about two-thirds of the way through the manuscript, the illuminations were left partially painted and the last tenth just has ink drawings of what should have been painted (illus. 6–7).
Today, the Metz Pontifical is split into two parts. Some of it is in the Fitzwilliam Museum, Cambridge, while the rest of it is in the University Library, Prague. The Cambridge part was donated in 1918 by Henry Yates Thompson, who received it as a gift from Sir Thomas Brooke, who had in turn acquired it at a Paris auction in 1817. According to art historians, all the Pontifical’s illuminations were painted by a single person, but very little is known about him or her apart from showing similarities with the ‘Cholet Group’ of painters in Paris.2
The painter left no known written record of their working practice so their attitude towards materials can only be sought from their paintings. However, a few other painters did leave records of their work and these artists’ manuals set the scene for approaching how two blue pigments were used in the Pontifical.
Artists wrote about the technology of painting, but of course, there is also a technology of writing. In the Middle Ages, writing technology was quite limited – all you needed was some ink, a quill and parchment. Most of those who wrote would have made their own ink and quills and prepared their own parchment, at least in their youth if not when older. They had to know how to make inks that would not fade, quills that would not blot and parchments that would not rot. Yet some writers knew a great deal more than was technically necessary for the practice of putting quill to parchment. Chaucer, for example, had a detailed knowledge of alchemy, and was also a skilled astrologer.3 Indeed, he even built an astrolabe to help teach his son Lewis about the skies.4
In general, writers just needed to know that oak galls, boiled up with a rusty nail while chanting paternosters, would give them a good black ink. They may not have known why a good black ink came from oak and iron. Although if they thought about it – as someone like Chaucer almost certainly did – they would have seen that it was entirely appropriate to use oak to make words because the first prophetic utterances came from an oak tree.5 It was also entirely appropriate to use iron to transform ephemeral utterances into permanent marks since iron tools were used to shape and fix wood. Ink’s ingredients also had astrological associations. Oak is the king of trees and Homer mentioned an oak sacred to Zeus – the Greek equivalent of Jupiter, king of gods – who spoke through the whispering of its leaves.6 Moreover, just as lead was governed by Saturn, so iron was governed by Mars.7 And some writers were evidently inspired by technical aspects of their craft. For example, just 60 lines from the end of his 14,243-line poem, in order to describe his understanding of everything in the universe in ‘a single moment’, Dante alludes to the final process of manuscript production – the binding of all the leaves into a single volume.8
6 Metz Pontifical, detail (f129r); initial preparatory drawings for an illumination and initial.
From a technical point of view, painting was a much more complicated business than writing. Painters needed to know how lots of different materials behaved. And, to get the best out of their materials, good painters also needed to have some idea about why those materials behaved as they did. They needed to make and mix colours – bright and dark, brash and subtle, opaque and transparent, crisp and blended – in order to achieve their art. They were much more dependent upon technology than writers and their technologies were intimately linked to traditional cosmologies.9 So, if even writers like Chaucer or Shakespeare were familiar with cosmology, when the act of writing required relatively little technology, it is safe to assume that good painters knew their cosmology too.
The part of cosmology most relevant to art materials was alchemy, as the painter Cennini specifically acknowledged.10 But he wrote a manual, so he was obviously interested in materials, whereas his interest may not have been shared by other artists, the vast majority of whom – like whoever painted the Pontifical – did not write manuals. However, the images to be considered in this chapter are manuscript illuminations, so it is worth noting that one manuscript illuminator also happened to be the most famous European alchemist of all time.
7 Metz Pontifical, detail (f123r); lower paint layers over an initial drawing in an unfinished illumination and initial.
Nicolas Flamel was born around 1330, lived in Paris and worked as a bookseller, notary, scribe and illuminator. Legend has it that one night he had a dream in which an angel showed him an enigmatically illuminated manuscript. Some time later, he was offered an old book that he recognized as the one in his dream. He bought it and immediately sought advice about deciphering its mysterious images. One day, a doctor visited his shop and offered an alchemical interpretation. Without delay, Flamel embarked upon a series of experiments that lasted 21 years. Success evaded him. In bearing in mind that the book was written by ‘Abraham the Jew’, he resolved to find a Jew who might understand it. So in 1378 he set off for Santiago de Compostela, Spain, and spent a year visiting synagogues. Eventually, he met a man who was able to help. He returned to France with one Maître Canches, who was evidently well versed in Kabbalah.
Tragically, Canches died before they reached Paris. However, Flamel had learned enough and it is said that after three more years he successfully transmuted base metal into gold, assisted by his wife Pernelle. Support for the Flamels’ claim to making gold has been found in their numerous charitable acts. In Paris, these included the foundation and endowment of fourteen hospitals and the building of three chapels as well as gifts to, and repair of, several other churches. Similar benefactions were made in Pernelle’s home town of Boulogne. Nicolas died in 1417, and his tombstone is now in the Musée National du Moyen Âge (Musée de Cluny), Paris.11
Nicolas Flamel seems to have been an exceptional alchemist, so his knowledge of materials was obviously greater than that of most manuscript illuminators. One cannot generalize about any professional group, but this book focuses on the work done by exceptional painters and, as will be seen, one thing that marks great painters is their interest in materials.
Nicolas Flamel, the alchemist-illuminator, shows that there was no great divide between science and art. Many famous artists dabbled in the sciences, but Vasari, painter and commentator, seemed to disapprove and complained about Parmigianino ‘wearing-out his brains’ on alchemy.12 While some evidence – like Cennini’s recipes and Vasari’s comments – is written, most of it is painted. For example, alchemical subtexts have been identified in Hieronymus Bosch’s almost hallucinogenic paintings. His densely populated, nightmare-like landscapes are fertile ground for all sorts of symbolism, and alchemy doubtless contributes meaning to his imagery. The alchemical content of Bosch’s paintings has been written about widely but alchemical ideas are also at the heart of much less bizarre paintings.
One such painting is by Lucas Cranach, who would have had easy access to all the alchemical materials and equipment that he might have wanted, from the pharmacy he owned in Wittenberg. Whether he actually practised alchemy is open to question, but he was close friends with teachers at the University of Wittenberg (where Hamlet learned to welcome strangeness13) and his Judgement of Paris has been identified as an alchemical allegory. This tale of an ancient beauty contest was a popular subject for painting since it involved three naked women in an idyllic landscape.14 There is nothing obviously alchemical in Cranach’s version and, for the last few centuries, most people will have completely missed its subtext. Yet there is no doubt that Cranach intended his painting to be interpreted as an alchemical, as well as classical and erotic, image.
At the time that Cranach painted his Judgement, a treatise circulated around Wittenberg containing woodcuts in which the three goddesses represented key stages of the alchemical Great Work. Athena, Juno and Venus were nigredo, albedo and rubedo, or blackening, whitening and reddening, respectively. Cranach painted Mercury, Paris (the judge of the beauty contest) and the goddesses with attributes that discreetly allude to these alchemical transformations. He also brought the subject closer to home by placing the figures in a landscape based upon the river Elbe and local Saxony mountains Rauenstein, Lilienstein and Königstein. The names of the river (literally, White) and mountains (Raw-stone, Stone of the Lily and King’s Stone) all relate to alchemical processes. And Cranach unobtrusively hinted at his alchemical interests with his chosen graphic signature – a tiny winged serpent.15
The artist who painted the Pontifical illuminations considered in this chapter did not depict anything bizarre like Bosch, or leave cryptic signatures like Cranach. The artist’s identity is unknown but some clues to his or her possible interest in materials can be found by looking at his or her fellow painters.
The painter’s prototype in the Christian tradition is St Luke and, as was appropriate for those who followed in the footsteps of a saint, painting was a sacred activity. This is made clear in the introduction to one painter’s manual that says those who wish ‘to learn the science of painting’ must first carry out
a preliminary training for a set period … then let there be
a prayer on his behalf … with the fear of God and the veneration
due to a sacred task.16
This particular manual outlines the icon painting tradition, but there were many contacts between the Byzantine East and the Latin West.17
Since painting was an appropriate activity for a saint, it is not surprising that painters were often monks, like Theophilus (who described how to make lead white). Some scholars suspect that Theophilus – ‘Lover of God’, a pseudonym adopted for the sake of humility – lived in northwest Germany and wrote his treatise as an old man.18 Engagement in contemporary theological debates enables the manuscript to be dated to around the 1120s.19 In fact, it is more likely that several people wrote the manual now attributed to him. This would not be unprecedented since Merlin and Hermes – other ‘authorities’ cited in this book – were also composite identities. But whoever wrote Theophilus’ treatise, he, she or they give the impression of not neglecting the spiritual side of life, seeing themselves as created in the image of God, as Homo faber, or ‘man the maker’, and treating the artist’s creative act as an echo of God’s creative act.20 Given Theophilus’ stated desire for anonymity, it is fitting that we will never know the authors’ exact identities.
Gradually, artist-monks like Theophilus were replaced by lay-artists like Cennino Cennini (the painter who did not make lead white but only called it ‘alchemical’). Unlike Theophilus, Cennini probably was the sole author of his treatise. All that is known about him is that he was born in Colle di Val d’ Elsa, midway between Florence and Siena, and that he trained in Florence under Agnolo di Taddeo Gaddi, whose father’s father was trained by Giotto. He probably worked in Padua and then returned to his home town (his son was recorded living near Colle in 1427).21 Cennini wrote his manual sometime between 1390 and 1430. He was not a monk, but his manual suggests that, like Theophilus, he had a spiritual approach to his work and practical aspects of his work were closely connected with the Church.22 For example, the Church commissioned many of his paintings and he recommended asking ‘friars’ about how to make vermilion, one of his materials.23 (He was probably referring to the Jesuits of S. Giusto alle Mura in Florence, who became famous for their ultramarine and who, in 1508, provided Michelangelo with blue for the Sistine Chapel.24) So, the artist-monk endured, making pigments, if fewer paintings.
To a greater or lesser extent, lay artists like Cennini continued the practices established by clerical predecessors like Theophilus. This is perhaps not surprising, since up to the fifteenth century work of all sorts was still seen as a spiritual discipline.25 The traditional European approach to painting was stable and enduring but, from the fifteenth century onwards, the interest of artists in their materials can no longer be assumed. For example, one of the earliest voices of modernism in art, Leon Battista Alberti, specifically tried to distance the practice of painting from a spiritual science of materials.26 In 1436, alluding to the elemental composition of pigments, he wrote:
Let us omit the debate of philosophers where the original source of colours is investigated, for what help is it for a painter to know in what mixture, rare and dense, warm and dry, cold and moist, colour exists?27
It is important to note that Alberti’s ‘original source of colours’ is exactly the same as that of Chaucer’s Doctor’s ‘cause of every malady’.28 This not only reinforces the impression that knowledge of artists’ materials was widespread, but it also offers clues about how paintings could interact with their viewers.
If a painter like Alberti professed little interest in materials, then the person who painted the Pontifical was probably more like Flamel than Alberti – they were certainly closer to Flamel in space and time than they were to Alberti. And if, like Flamel, they were interested in alchemy, then they were not blatant, like Bosch, but circumspect, like Cranach. In the absence of any written statements by the Pontifical’s painter, we must turn to their paintings as ‘silent witnesses’ to their thoughts and deeds.
The act of examining the Pontifical as a silent witness is quite different from the forensic examination of a crime scene – criminals want to hide their tracks, whereas artists want to share their work as widely and as deeply as possible. An artist’s work may be in front of our eyes, but if we do not know how it was made, then some of its meaning is lost and the artist’s desire to share their gift is frustrated.
As a conservation scientist, I am in a privileged position – I have the opportunity to examine paintings very closely indeed. Usually, examination is part of assessing their conservation needs but I looked at the Pontifical just to see how it was made. I routinely use a range of scientific methods (including many of those used to investigate crime scenes) and they can be divided into those that require samples and those that do not (illus. 8).
Today, if we want to know how historic paintings were made, some sort of scientific examination is necessary because the live transmission of knowledge – from master to apprentice – stopped several hundred years ago. When painters no longer trained as apprentices, they became self-taught or were taught in academies. However, many teachers in the academies – like Sir Joshua Reynolds – taught themselves. So, in the eighteenth century, with an interest in Old Master paintings but with no master to help him, Reynolds was reduced to buying paintings, dissolving them with solvents and dissecting them with scalpels to discover how the masters achieved their wonderful effects.29 Modern science allows Old Master paintings to be studied without destroying them. It offers technical insights that can add pieces to the jigsaw puzzle and can sometimes help to complete the picture. Artists wanted to share their inspiration, and when science provides a key piece of information, it makes you feel as if you can travel back in time and glimpse them at work.
8 The author examining the Metz Pontifical in the Fitzwilliam Museum’s conservation studio. |
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Observations made with the naked eye and aided by a stereomicroscope provide the context in which to interpret the scientific examination.
Non-sampling methods of examination can be divided into two groups: those where an image of the whole painting is provided, and those where details about a tiny area are provided. The first group includes X-radiography, ultraviolet fluorescence (UV), infrared reflectography (IR) and multispectral analysis (MA). X-rays penetrate the whole structure and give clues about every layer of the painting; UV interacts with the surface layers only and gives clues about varnish and some pigments; IR penetrates some paint layers and gives clues about some pigments and some hidden drawings; MA can identify some pigments and media. The second group – non-sampling methods that look at small areas – include various types of spectroscopy, such as x-ray fluorescence, Micro-Raman, Fourier transform infrared, infrared/visible and visible/ultraviolet. Recent advances mean that these processes are now starting to be used to scan surfaces and generate spectral maps of larger areas of paintings.
Sampling methods require a microscopic piece of paint to be taken from the work of art. This happens only after discussion with art historians, museum curators and, of course, the painting’s owner(s). The samples range in size from a speck of dust that cannot be seen by the naked eye to a ‘chip’ about the size of a printed full stop, which are taken from the edges of existing damages to the work. Such samples are prepared and examined by polarized light (PLM), reflected light (RLM) or scanning electron microscopy (SEM), or by high pressure performance liquid (HPLC) or gas chromatography (GC). PLM allows the identification of many pigments; RLM shows how the artist prepared and applied paint; SEM elaborates on the findings of PLM and RLM; HPLC identifies some pigments and media; and GC, in tandem with Mass Spectrometry, identifies media destructively.
9 Photograph of one of the finished illuminations (f23v) in the Metz Pontifical, which was taken by a camera sensitive only to infrared light (see illus. 10). Note that all of the blues in the background pattern (azurite) appear dark and those that make up the robes (ultramarine) appear light. This pattern of pigment use is consistent through the whole manuscript and is evident in the unfinished illuminations (see illus. 12) as well as the infrared reflectography images of every single finished illumination.
The Pontifical was examined in an airy conservation studio with plenty of UV-filtered natural daylight. It lay open, tilted up on a bench with foam supports to reduce the stress on its spine. An infrared camera on a tripod provided a life-sized image of the open folio on an adjacent laptop. The manuscript displayed a rich pattern of colours and textures, while the computer screen showed a clinical, black-and-white image.
By eye, all the rich midnight blues in the illuminations looked similarly dark and, in a black-and-white photo, you would expect them all to come out as similar shades of grey. At first glance, the image on the computer screen looked just like a black-and-white photo of the vibrant illumination in the manuscript (illus. 9). All the dark blues in the background looked black. But then, scanning along a row of robed monks, the shades of grey on the screen did not correspond to the tones in the illumination. A monk who wore a dark blue robe in the manuscript looked as if he was clad in white on the computer screen. The difference was so surprising that I checked to see if the image was live and if the camera was pointing at the right illumination. I examined the whole manuscript and the same thing happened again and again – on the computer screen, some of the blues looked black and some looked white.
When I first looked at the Pontifical, I did not notice any difference between the blues (illus. 10). However, after the infrared camera showed that there was a difference, I found that I could distinguish them by eye – one was more opaque and the other was more transparent. There was nothing to suggest that the painter was using different media (resins, gum arabic, egg tempera or rabbitskin glue, for instance) in the different areas, so the infrared suggested that the painter was using two different blue pigments.30
Scientific examination showed that there was no cross-contamination between the two blues. Both were either prepared pure in the workshop or were bought pure from an apothecary, and then kept and used separately. The separation of these two virtually indistinguishable blues was clinical. In order to achieve such strict segregation, each blue must have had its own dedicated set of brushes, pots and palettes. The painter probably even used different blues on different days to avoid confusing them.
10 Detail showing the visible image of the illumination from the Metz Pontifical, f23v (illus. 9).
Such a consistent and controlled approach to pigments seems to fit with the artist’s systematic approach to the whole manuscript – visible in the unfinished illuminations – with neat line drawings, methodical buildups of colour and crisp finishing outlines. Yet the complete separation of pigments was not restricted to the two blues, nor was it just the personal style of the Pontifical’s unknown painter. For example, scientific examination has shown that, over 300 years later, Rembrandt’s apparently carefree and spontaneous paintings were made in exactly the same meticulous manner.31 The chaotic modern studios of painters like the late Francis Bacon are a very far cry from Rembrandt’s studio or the workshop in which the Pontifical was created.
It would, though, all have been so much easier if the painters had used only one blue. And, if they had chosen only the cheaper one, the Pontifical would have been considerably less expensive. Since the two blues look practically the same, the presence of both is something of a riddle. However, the artist’s reasons for using both blues start to become clearer when they are compared as raw materials. The comparison suggests that this particular painter – and, more importantly, their patron – did indeed care about the nature of their materials and that they used materials to give their imagery an extra level of meaning above and beyond their colours.
An artist’s manual distinguished between the two blue pigments, calling one ‘terrestrial’ and the other celestial.32 The celestial one cost about ten times as much as the terrestrial version.33 However, one of them did not fall from heaven – no blue matter can be extracted from the sky – both were dug up from the earth. Considering lead white in its cultural context showed that the pigment had values for painters, some of which were recognized even by those not initiated into the craft mystery. Similarly, putting the two powdered rocks back into their cultural contexts helps unravel the riddle of their (practically invisible) difference – their costs, for example, reflected where the two rocks came from and how they were used outside the artist’s workshop. Such details must have been very common knowledge otherwise the price difference could not have been justified or maintained.
Nature does not provide many blue rocks, and not all of them would be suitable to make paint – ground-up sapphire, for example, would be too transparent to make good paint. The Pontifical’s most expensive blue pigment was ultramarine. Modern science would describe ultramarine as the mineral ‘lazurite’, a complex aluminosilicate, which is found mixed with other coloured minerals in the stone called lapis lazuli.34 In the early nineteenth century, ultramarine was still such an important material that several European governments established international competitions encouraging scientists to make it artificially.35 The Pontifical’s cheaper blue was the mineral ‘azurite’, which modern science describes as a copper carbonate and which occurs in nature along with malachite, the decorative striped-green stone. Synthetic versions of azurite were manufactured by painters but azurite and its equivalents fell from favour towards the end of the seventeenth century.
Cennini mentioned that azurite ‘occurs extensively in Germany’.36 Some artists called it ‘German blue’ and others called it ‘Mountain blue’, since it was found in mountainous regions including Bohemia and Hungary. The names of German mountains in the background of Lucas Cranach’s Judgement of Paris suggested alchemical significance, and other German place names suggest the everyday importance of mountains. For example, the town of Freiburg, or ‘Free mountain’, suggests that the mountain was a source of wealth that gave freedom to the locals. And Blauberg, or ‘Blue mountain’, suggests that the local mountain was once coloured blue by deposits of azurite. The occurrence of azurite on mountain-sides was a clue that the interior contained copper and most people were interested in azurite as a visible pointer to hidden treasure. The mineral was one of Mother Earth’s signs, written in the Book of Nature that was eagerly read by metal prospectors. In fact, the first thing Cennini said about azurite in his manual for artists was that it ‘exists in and around veins of silver’.37 So, in the Middle Ages, the blueness of a mountain advertised a mineral wealth that could buy freedom. Most European ore deposits were small, though, and exhausted within a few generations so the freedom that copper and silver brought was short-lived. Stumbling across azurite could signal imminent wealth but that wealth was quickly followed by social upheaval and ecological damage, much like the discovery of oil and gas today.
Metz was close to Germany, so Renaud de Bar and his mother probably knew the cheaper – German, mountain or terrestrial – blue’s cultural background. And they would certainly have known all about the Pontifical’s other blue which was one of the most expensive of all artists’ materials, often worth its weight in gold. Its expense was due to the rarity of the raw material and competing uses for it outside the workshop. The raw material was lapis lazuli, and in the Middle Ages there was only one source of lapis in the whole world – Afghanistan. (Recently, other sources have been found in Siberia and Chile.) The mines in Afghanistan have been continuously active for thousands of years. They supplied the Ancient Egyptians with lapis for jewellery and amulets, and they are still producing lapis today.
In the 1270s and 1280s, when the Pontifical’s painter was still a child or maybe an apprentice, Marco Polo visited Afghanistan and mentioned its rich mines. He said that there was a mountain of lapis in the region of Badakhshan (along with another of ruby and a third of sapphire).38 Furthermore, Tenduc, further east, produced plentiful excellent lapis.39 The mines are extremely remote, up precipitous mountainsides and cut off by snow for nine months of the year. It is very unlikely that Marco Polo actually saw them with his own eyes because not even the Mughal emperor Babur managed to see them in 910 AH (1504–5 AD).40 The mines had a certain mystique that painters and patrons would have appreciated – while no Europeans had seen them, everyone knew the significance of their general location. Marco Polo identified Tenduc as the utopian kingdom of Prester John, the legendary Christian enclave in the Himalayas.41
So, the expensive blue came from an earthly paradise, identified on European maps as part of the mystic East, near the home of the magi who rode westward to pay homage to the Christ-child in Bethlehem. The celestial blue started its journey to Europe from Kabul, which reinforces the stone’s connections with an earthly paradise, since Kabul was once known as the ‘city of gardens’ – the word ‘paradise’ comes from the Persian for ‘garden’ – and the city’s climate was so agreeable that ‘if the world has another so pleasant, it is not known’.42
Lapis made its way to Europe along with silks and spices, and when it arrived in Venice, it was in great demand as a gemstone, a pigment and a drug with a surprising number of applications. Pope John XXI (1276–7) recommended the polished stone in the treatment of eye conditions, and the powdered blue was used to treat snake bites, fever and headaches.43 In addition to its physiological properties, lapis also had psychological powers, for example, it induced tranquillity and dispelled melancholy.44 Jewellery that incorporated lapis was like a portable medicine cabinet.45
The powers of lapis did not always require ingestion of the powder or touching of the polished surface. For example, simply wearing lapis protected the wearer from witchcraft and gazing upon it promoted visions.46 This suggests that the diviner’s mental state was influenced by the mere sight of the rock, which, of course, is completely consistent with the artist Lomazzo’s statement that ‘colours have different qualities, therefore they cause diverse effects in the beholders’.47
The use of lapis as a drug, as a gem and as an amulet suggests that artists had to compete for it in the marketplace with physicians, jewellers and magicians. This, in part, accounts for its high price. More importantly, these other uses reinforce the idea that colours, pigments and images had powers that influenced their beholders. Bishop Renaud de Bar, who commissioned the Pontifical, would have been aware of these properties. After all, a Pope had written about the stone and its powers just a few decades earlier, and another French bishop, Marbode of Rennes, had written a long poem about it 200 years earlier. Marbode said that lapis was
By nature with superior honours graced,
As gem of gems above all others placed;
Health to preserve, and treachery to disarm,
And guards the wearer from intended harm:
No envy bends him, and no terror shakes;
The captive’s chains its mighty virtue breaks;
The gates fly open, fetters fall away,
And sends their prisoner to the light of day.
Even Heaven is moved by its force divine,
To list the vows presented at its shrine.
Its soothing power contentions fierce controls,
And in sweet concord binds discordant souls;
Above all others this Magicians love
Which draws responses from the realms above:
The body’s ills its saving force allays
And cools the flame that on entrails preys.
Can check the sweats that melt the waning force
And stay the ulcer in its festering course:
Dissolved in milk it clears the cloud away
From the dimmed eye and pours the perfect day;
Relieves the aching brow when racked with pain
And bids the tongue its wonted vigour gain,
But he who dares to wear this gem divine
Like snow in perfect chastity must shine.48
No such poem was written about azurite, the Pontifical’s cheap, terrestrial, blue.
The preparation of the two powdered blue rocks was an artist’s secret, part of the craft mystery. Cennini wrote a long and very detailed account of preparing ultramarine because the colour was
illustrious, beautiful, and most perfect, beyond all other colours; one could not say anything about it, or do anything with it, that its quality would still not surpass.49
Ultramarine’s preparation has been examined in detail in The Alchemy of Paint, but something must be said here in order to show how it differs from azurite’s preparation. Lapis is a mixture of three minerals – a white, a blue and a gold – that have to be separated to make a pure blue paint. The rock is ground up in a bronze mortar, the powder worked up on a porphyry slab, combined with wax, gum and resin, and warmed to make a hard paste-ball which is then kneaded with oiled hands for at least three days. The paste-ball is then placed in a bowl of warm lye (a caustic solution made from wood ash and water) and kneaded with sticks until the lye turns blue. According to Cennini, this stage is repeated eighteen times. The best blue is released into the lye first, and as the process continues, the quality of the colour declines as more and more of the white slowly emerges from the ball. All of the gold mineral stayed in the paste-ball. Every single detail is consistent with theories of matter documented 400 years before Christ.50
The ultramarine on medieval paintings is a softer, richer colour than modern French ultramarine, so to get the real thing, I had to get some Afghan lapis and follow Cennini’s instructions. The process is much more difficult than the synthesis of lead white. Cennini said that it was work for ‘pretty girls’, not ‘for men’, but I found kneading a ball of ground-up rock, hot wax and resin to be hard work, and kneading it under water with sticks takes considerable skill.51 Yet, even in my unskilled hands, the recipe worked exactly as described. I took the raw lapis and samples of each extracted batch and analysed them in a Scanning Electron Microscope. The first batch was the purest and successive batches became more and more contaminated with the white minerals. The gold mineral was nowhere to be seen.52
Many artists, over many centuries, wrote about how to purify lapis. No one, though, wrote in such detail about purifying azurite – the few recipes that exist are all quite short. Purifying azurite is not so labour-intensive and it does not require complicated mixtures of waxes, gum, resins or oils and lye. Most recipes just refer to ‘washing’ the powdered rock, although some advise adding things like honey to the water and some recommend timing with chanted paternosters.53
The artist’s purification of azurite harnessed the way the powdered rock behaved naturally in their workshops. As the scientific examination of the Pontifical demonstrated, the painter’s use of pigments was very methodical with separate brushes, palettes and pots for each colour. Because colours were valuable, painters recycled whatever was left in the brush and on the palette at the end of the day’s work. And when the very earliest painters recycled their azurite, they would have noticed that the pigment at the bottom of the pot was not all the same colour, even though it all looked the same when it was on their brushes.
After a day or so, when the water in the pot had cleared, these artists would have seen a very pale-blue layer at the bottom. And when they gently poured off the clear water and scooped up the sludge to reuse it, they would have noticed that the visible pale blue was a very thin skin that hid a much darker blue layer (illus. 11). The precious sludge showed that what looked like a uniform blue powder was actually a mixture of blues that could be separated. When artists washed their brushes in water, the dark blue settled to the bottom of the pot quickly, and the lighter blue took a couple of days to settle.
So, straight after grinding up the rock, rather than using it immediately, later artists, like the Pontifical’s illuminator, took the apparently uniform blue powder and ‘washed’ it in water. They rubbed it between their fingers or against the side of the pot and then decanted the still cloudy liquid into another pot. That way, they collected the darker particles of azurite in one pot and the lighter particles in another pot. By repeatedly washing, allowing the powder to partially settle and then decanting, they eventually arrived at different grades of azurite – from a relatively expensive midnight blue all the way to a really cheap, insipid blue.
The artists sorted colours with rhythmic, meditative gestures. The first involved massaging the pigment under water with a motion like blending butter and flour. It was gentle and relaxing, not unlike passing rosary beads between fingers and thumb. The second gesture involved swirling the pot and pouring off the partly suspended, partly deposited azurite. This was like the circular motions used by someone making paper with pulp in a sieve or by a prospector panning for gold on a riverbank. By repeating these movements over and over again, the dark-blue particles were gradually concentrated at the bottom of a pot as the suspended light-blue particles were poured off in the water. It is impossible to describe the sequence of fluid gestures that culminated in one pot of midnight blue and other pots of increasingly pale blues. No one bothered to try to write about it in manuals for artists. They just learned by watching their master and copying, and everyone who purified azurite would have developed their own personal style of washing.
When I tried grinding and washing azurite, the process worked quite well but it was obvious that much practice would be needed before I could get comfortable and develop my own style to sort the rich from the insipid blue.54 I also found that it was a wonderful way of getting into a calm, receptive frame of mind ready for painting. The process has its own pace and cannot be hurried – if you accept its pace, it becomes completely hypnotic. The sequence of rhythmic motions take on a dance-like quality akin to the performance of a rite that cleanses the mind as it cleans the pigment.
11 The bottom of a jar of water containing settled azurite. The dark layer at the bottom consists of particles 10 microns or more in size (approximately one hundredth of 1 mm across). Above that is a paler blue consisting of particles of between about 10 and 1 microns. At the top is a very thin layer of white, particles of less than 1 micron (under one thousandth of 1 mm across). Some of the sub-micron dust has adhered to the edge of the glass. It seems remarkable that with some clean water, a few pots, some patience and a lot of skill, artists could separate this precious powder with such accuracy.
When this massaging, swirling and pouring was timed with chanted paternosters or Ave Marias, as many manuals recommend, then the act of washing azurite would have been profoundly meditative. Artists could have compared it to separating the ‘wheat from the chaff’ since the pale, low-grade azurite was like ‘the chaff that the wind driveth away’.55 (The main difference was that the chaff-like pale-blue was driven away with water, not wind, and was worth keeping as a low-grade pigment.) Since the low-grade, pale azurite was like ‘ungodly’ chaff, it follows that the high-grade, rich midnight blue could be considered ‘godly’. Indeed, the rich blue’s ‘godliness’ is reinforced by being the product of what the Psalms called the ‘right hand’s cunning’ which, according to St Jerome, did the Lord’s work.56 It was entirely appropriate that, in the hands of a skilled artist, a cunning meditative process could convert a cheap, terrestrial blue into something that looked almost exactly the same as the expensive, celestial blue.
The two blue paints in the Pontifical looked only very subtly different to my eye. But of course, it was always possible that my eyes were not as good as the eyes of a painter who worked with the blues everyday. Yet physical evidence in the manuscript suggested that my eyes were not significantly worse than the average medieval artist’s eyes.
When the Pontifical changed hands, an artist was employed to scrape off and paint over the coats of arms of Renaud de Bar and his mother Mme Châtillon-Toucy. The later artist who was given the task of removing and covering them saw the original artist’s deep, rich blue around the coats of arms and assumed that this was the best pigment available. So, after scraping off much of the original, he or she painted over the remaining traces with the most expensive blue to match. The match is quite good, so the naked eye initially fails to notice that the later blue is not the same as the original blue. However, actually, the original artist used the cheaper ‘terrestrial’ azure for the blue background. The later painter was trying to do the right thing – he or she saw the quality of the original and did not pick the cheapest blue to cut costs, but mistakenly used their most expensive ‘celestial’ azure. The confusion between the original and later blues on the coats of arms only becomes obvious when the manuscript is examined with an infrared camera. So, if a later medieval painter could not distinguish between the two blue paints, it is quite safe to assume that Renaud and his mother would not have known which blue was used. And it is highly unlikely that the bishop or his mother would have spent much time in the workshop, looking over the painter’s shoulder, checking whether the expensive blue was actually used rather than hoarded for another job or put aside as a drug in case of fever or melancholy. (The patron and painter evidently had a good relationship because they were both also jointly responsible for a missal – instructions and texts for the Mass – and a breviary – book of canonical prayers.57)
A skilled eye might just be able distinguish between the two blue paints, but before the two ground-up rocks were mixed with a medium-like gum, egg or glue, they were actually impossible to tell apart by eye. Artists – and those buying anti-inflammatory and antidepressant ultramarine who did not want their drug to be cut with azurite – had to test the powders to find out which was which. Their test involved placing a pinch of the unknown blue on a poker and gently putting it in a fire. When the poker glowed red hot, it was carefully taken out of the fire and the tiny pile of powder was examined. One of the blues would turn black, while the other would be unchanged. It should come as no surprise that the one that failed its trial by fire was the cheap terrestrial blue, azurite, and the one that survived trial by fire was the expensive celestial blue, ultramarine.58
If painters made their own pigments, then they already knew which was which and they did not need to test them. However, if they wanted to buy ready-prepared pigment from an apothecary, then – since one cost ten times as much as the other – they would want to know that the expensive blue powder was not substituted with, or adulterated by, the cheaper one. They would want to know which blue they were buying because professional regulations governed the use of particular pigments. The Statutes of the Painter’s Guild of Siena, for example, imposed a fine of ten lire on anyone who fraudulently substituted azurite for ultramarine.59
Guild regulations show that artists could use, and contracts show that patrons could specify, one blue or the other. With a factor-of-ten difference in price, there were good reasons for using one or the other and, in fact, many paintings did use only one of them.60 But the Pontifical has both and, while practically indistinguishable, they were not used interchangeably. The unfinished state of the illuminations provides evidence of the order of work and the Pontifical did not start with the expensive blue and move to the cheaper one or visa versa. There is no evidence that the patron ran out of, or came into money as the work progressed. There is a clear and consistent distinction between the two blues at every stage of production.
12 Metz Pontifical, detail (f117r) of an unfinished illumination with pale, cheap azurite as the underlayer for the borders.
Both pigments were available in a number of grades. Ultramarine could be the rich blue that was the first to be released from the kneaded paste-ball or the paler version that contained more white mineral. Similarly, azurite could be the rich blue that settled in water quickly or the paler version that contained more pigment dust. All the Pontifical’s ultramarine was the rich, top grade, but the azurite was present in a pale lower grade as well as a top grade that looked like ultramarine.
The low-grade azurite – terrestrial azure’s ‘chaff’ – was used as a preparatory underlayer and is visible as flat blocks of colour in the unfinished illuminations towards the end of the manuscript (illus. 12). It was used as the first layer in borders around illuminations and it allowed the second layer of ultramarine to be painted much thinner, and therefore more economically, while still creating a rich visual effect. Cennini’s manual, written 50 or more years after the Pontifical was painted, recommended separate layers of cheap blue covered by layers of expensive blue, exactly as found in the Pontifical’s borders.61 Once alerted to the painter’s technique, the pale azurite is also just visible in the blue borders of finished illuminations. It is the ‘neon-glow’ that seems to emanate from the decorative line of lead white. The second layer of ultramarine was applied after the white and did not extend all the way across the azurite, fading out as it got closer to the line. The same technique was used on red borders with a flat block of pale red followed by a more expensive, transparent red roughly painted around the decorative line of lead white.
So both blues – the cheapest version of the cheap blue underneath and the most expensive version of the expensive blue on top – were used around the illuminations. Elsewhere, though, the two blues were completely separate. Throughout the manuscript, the expensive blue was always used in robes and the almost identically coloured top grade of the cheaper one was always used in backgrounds. The two blues were never mixed within a single passage or a single layer.
Some technical differences between the two blues suggested how the painter should use them. For example, putting a thin layer of ultramarine above a layer of azurite made perfect sense optically, since ultramarine makes a more transparent paint and azurite makes a more opaque one. Painting ultramarine over azurite allows the lower blue to shine through the upper one, but reversing the sequence of painting would be a waste of time and money since the opaque azurite would hide the transparent ultramarine. But practicality does not explain the artist’s use of a transparent paint over an opaque one. The painter’s practice involved putting the celestial azure over the terrestrial one – reversing the sequence of painting would have put the earthly pigment above the heavenly one. Symbolically, it would simply be wrong.
In 1273, 30 years before Renaud became Bishop of Metz, Robert Kilwardby became Archbishop of Canterbury, and he said ‘the practical sciences are speculative’.62 He was quoted in the previous chapter in the context of pigment science, but his reminder is equally relevant to ‘the science of painting’.63 ‘Speculative’ literally means ‘as if reflected in a speculum’ or mirror, so Kilwardby’s statement can be taken to mean that all practical sciences are mirrors that reflect a higher reality. Today, we usually think that reflecting reality in a painting involves copying the appearance of nature. However, the Pontifical’s strictly segregated use of two blue pigments obviously does not copy the appearance of nature, since they look the same. A late fourteenth-century Paris master famously said, ‘Art without science is nothing’, and the ‘speculative’ side of the science was more about how things worked in the cosmic scheme of things rather than how they looked.64 As Thomas Aquinas put it, ‘Art imitates nature in her manner of operation.’65 This was acknowledged by alchemists and physicians such as Petrus Bonus who said, ‘Art imitates the method of Nature.’66 It was also acknowledged by painters, like Theophilus, who in the prologue to his manual, said that art ‘reflects Nature which in turn reflects God’.67
So, whoever painted the Pontifical would have taken the fact that the use of some method was practical – like a transparent layer over an opaque one – as physical proof that it reflected a spiritual truth. Following in the footsteps of St Luke, their vocation was both practical and spiritual and it was not by chance that preparing the pigments for painting also prepared the painter for painting. Nor was it by chance that the layers on the velum reflected the world outside the workshop, with the heavenly above the earthly.
Whichever way you look at it, the Pontifical’s painter used the two blues in an appropriate manner. The use of blues satisfied painter and patron both materially and spiritually because the materials were understood within an all-encompassing cosmology. That cosmology saw the individual as a spirit, soul and body and as a reflection of the whole world. The practical use of the blues resonated with the painter’s bodily actions, the sensuous effect of the blues touched the souls of the painter and the patron and, as will be seen in a later chapter, the spiritual side of the blues was in complete accord with the manuscript’s functions. The (microcosmic) body, soul and spirit were satisfied by the distinctions made between visually indistinguishable blues because of the way the blue rocks existed in the (macrocosmic) world.
The two rocks came from different places. One came from just down the road, associated with the boom and bust of European metal prospecting, while the other came from the doorstep of Paradise, from unseen mines that kept giving for millennia. One was stumbled upon fortuitously in the search for greater riches, while the other was sought after at great peril for its own sake.
The two blues also required different preparation once they got to the workshop. One process could not be described and followed a chance workshop observation. The other was lovingly written about in great detail, since it was in perfect accord with theories of matter and harnessed elemental desires that were completely comprehensible at every level.
Both blues were purified by ‘cunning’ hands. One involved repeated rhythmic massaging, whirling and pouring, while the other required at least three days of steady kneading. So both offered equally meditative potential to practitioners and gave them time to consider the nature of the blues to which they devoted their labours. Painters knew that one of the blue powders they made would be mortified in the fire, while the other survived trial by fire. They also knew that one of them would make an opaque paint that hindered the passage of light, while the other would make a transparent paint that offered little resistance to light.
However the artists considered the two blues, ‘celestial’ ultramarine was superior to ‘terrestrial’ azurite. Ultramarine’s transparency was superior to azurite’s opacity, since transparent things participate in light more fully than opaque things and the origins of light are divine.68 Ultramarine’s response to fire was more worthy than azurite’s, like the noble metals that survive when baser metals are consumed in the furnace.69 Ultramarine’s labour-intensive and comprehensible processing was better than azurite’s easy, sensual processing because all good things were hard to obtain and because intelligibility was better than unintelligibility.70 Finally, ultramarine’s exotic origin was more desirable than azurite’s prosaic origins, and ultramarine’s single, reliable source was to be preferred over azurite’s multiple, erratic sources.
The patron – not necessarily privy to all the painter’s craft mysteries – may not have known quite how consistently superior ultramarine was, but whatever they did know evidently justified the considerable extra expense of using it in addition to azurite. The use of two blues made little visual difference to the illuminations so the reason for the patron’s extra expense must reside in the materials and their connection with the manuscript’s function.
The Pontifical was an official document. It outlined the services to be performed by a bishop, such as ceremonies for a church’s dedication or a monarch’s coronation.71 Most of the illuminations in the Pontifical were depictions of those rites being performed (illus. 13, 14). All images of rites involved a number of different people, each with their own roles, each to be fulfilled in a specified sequence of events. Sadly, Renaud de Bar died before the painter’s illuminations could help him in the performance of his duties (illus. 32). Yet his commissioning of the Pontifical initiated another sequence of events that involved many people with different roles to play.
For example, distant prospectors and miners – who knew absolutely nothing of Renaud’s plans for a Pontifical – had critical roles to play in the provision of its blues. The blue rocks then had to get to the artist’s workshop. The journey from a German mountainside to the workshop in northeast France was relatively straightforward, with the azurite changing hands between middle men and apothecaries. The journey from an Afghan mountainside was much more involved, with the lapis coming through many more hands, through desert caravans, Mediterranean ships and Venetian apothecaries. Then other, highly skilled hands had to perform complex operations to get pure blue powder out of the raw rocks. The presence of both blues in the workshop allowed another performance to take place, one that gave the Pontifical’s unknown painter the opportunity to choose between materials. Yet this last stage was unfinished, since Renaud’s death stopped play.
13 Metz Pontifical, detail (f14r) of a finished illumination.
The sequence of events that brought two pigments to a workshop in Metz cannot be reconstructed in detail. Everyone must have fulfilled their roles, but they left no trace of their individual activities. On the other hand, the Pontifical offers physical evidence that allows us to reconstruct the painter’s performance in the workshop, even though his or her identity is unknown.
The two blues were so well prepared that the painter could use the pigments’ non-visual qualities without compromising the visual qualities of the illuminations. And a summary of those non-visual qualities shows that ultramarine was superior to azurite in every way. The factor of ten price difference suggests that Renaud appreciated ultramarine’s superiority and considered it worth paying for a difference that he literally could not see. In other words – to answer the question posed at the beginning of this chapter – the cultural significance of an artist’s materials did indeed contribute meaning to the painted images.
The price difference and their placement within the Pontifical reflected a hierarchy among blue rocks. Aristotle claimed that all things seek the perfection of which they are capable, yet the degree of perfection of which a thing is capable is determined by what it is and how it expresses the options open to it. For example, most birds can fly, yet an eagle can soar, a hummingbird can hover, while a pigeon can soar a bit and hover a bit. According to this Aristotelian idea, the eagle perfects soaring, the hummingbird perfects hovering and the pigeon perfects adaptability. The options for perfection available in the animal kingdom are different from those in the mineral kingdom. Nonetheless, ultramarine evidently achieved a greater degree of perfection than azurite in their particular ways of expressing the options available to blue rocks. Both express an elemental wateriness, but ultramarine showed a greater sympathy with, or affinity to, elemental water than azurite.72 Exactly why ultramarine’s ‘wateriness’ was valued so highly in paintings will be explored in a later chapter.
Using the almost visually identical ultramarine and azurite side by side in the same illuminations allowed the patron and painter to play with degrees of perfection. As literal transcriptions of events taking place in church, the Pontifical’s pictures are all concerned with the strict decorum of formal occasions. It is therefore entirely appropriate that the unknown artist should have used the two blues formally and segregated them according to their difference in status. In the Pontifical, the pattern of blues reflected the pattern of Church life. The painter used the higher degree of watery mineral perfection, ‘celestial’ ultramarine, to clothe the clergy and the lower degree of watery mineral perfection, ‘terrestrial’ azurite, as the backdrop against which the clergy performed their rites.
Paintings are usually appreciated as examples of the visual arts, not as pieces of performance art. However, the two virtually indistinguishable blues suggest that the Pontifical could also be seen as the product of an extremely painstaking performance that took place, largely unobserved, over a number of years. The two blues show that the unknown painter paid almost ritual attention to detail when painting. The person who illuminated the manuscript approached it in the same manner as the person who was intending to use it. The painter and patron respected the natural hierarchies of the mineral realm, from which the Pontifical’s blues originated, and they respected the religious hierarchies of the cathedral, for which it was destined.
