On the production of ancient Egyptian blue: Multi-modal characterization and micron-scale luminescence mapping

The ancient pigment Egyptian blue has long been studied for its historical significance; however, recent work has shown that its unique visible induced luminescent property can be used both to identify the pigment and to inspire new materials with this characteristic. In this study, a multi-modal characterization approach is used to explore variations in ancient production of Egyptian blue from shabti statuettes found in the village of Deir el-Medina in Egypt (Luxor, West Bank) dating back to the New Kingdom (18^th-20^th Dynasties; about 1550–1077 BCE). Using quantitative SEM-EDS analysis, we identify two possible production groups of the Egyptian blue and demonstrate the presence of multiple phases within samples using cluster analysis and ternary diagram representations. Using both macro-scale non-invasive (X-rays fluorescence and multi-spectral imaging) and micro-sampling (SEM-EDS and Raman confocal microspectroscopy) techniques, we correlate photoluminescence and chemical composition of the ancient samples. We introduce Raman spectroscopic imaging as a means to capture simultaneously visible-induced luminesce and crystal structure and utilize it to identify two classes of luminescing and non-luminescing silicate phases in the pigment that may be connected to production technologies. The results presented here provide a new framework through which Egyptian blue can be studied and inform the design of new materials based on its luminescent property.

Ochre and pigment use at Hohle Fels cave: Results of the first systematic review of ochre and ochre-related artefacts from the Upper Palaeolithic in Germany

Though many European Upper Palaeolithic sites document early examples of symbolic material expressions (e.g., cave art, personal ornaments, figurines), there exist few reports on the use of earth pigments outside of cave art-and occasionally Neanderthal-contexts. Here, we present the first in-depth study of the diachronic changes in ochre use throughout an entire Upper Palaeolithic sequence at Hohle Fels cave, Germany, spanning from ca. 44,000-14,500 cal. yr. BP. A reassessment of the assemblage has yielded 869 individual ochre artefacts, of which 27 show traces of anthropogenic modification. The ochre artefacts are from all Upper Palaeolithic layers, stemming from the earliest Aurignacian horizons to the Holocene. This wide temporal spread demonstrates the long-term presence and continuity of ochre use in a part of Europe where it has not been systematically reported before. The anthropogenic modifications present on the ochre artefacts from the Gravettian and Magdalenian are consistent with pigment powder production, whereas the only modified piece from the Aurignacian displays a possible engraved motif. The non-modified artefacts show that more hematite-rich specular ochres as well as fine-grained deep red iron oxide clays were preferred during the Gravettian and Magdalenian, while the Aurignacian layers contain a broader array of colours and textures. Furthermore, numerous other artefacts such as faunal elements, personal ornaments, shells, and an ochre grindstone further strengthen the conclusion that ochre behaviours were well established during the onset of the Aurignacian and subsequently flourished throughout the Upper Palaeolithic at Hohle Fels cave.

Patterns of change and continuity in ochre use during the late Middle Stone Age of the Horn of Africa: The Porc-Epic Cave record

Ochre is found at numerous Middle Stone Age (MSA) sites and plays a key role in early modern human archaeology. Here we analyse the largest known East African MSA ochre assemblage, comprising 40 kg of ochre, found at Porc-Epic Cave, Ethiopia, spanning a period of at least 4,500 years. Visual characterisation of ochre types, microscopic identification of traces of modification, morphological and morphometric analysis of ochre pieces and modified areas, experimental reproduction of grinding processes, surface texture analysis of archaeological and experimentally ground ochre facets, laser granulometry of ochre powder produced experimentally on different grindstones and by Hamar and Ovahimba women from Ethiopia and Namibia respectively, were, for the first time, combined to explore diachronic shifts in ochre processing technology. Our results identify patterns of continuity in ochre acquisition, treatment and use reflecting both persistent use of the same geological resources and similar uses of iron-rich rocks by late MSA Porc-Epic inhabitants. Considering the large amount of ochre processed at the site, this continuity can be interpreted as the expression of a cohesive cultural adaptation, largely shared by all community members and consistently transmitted through time. A gradual shift in preferred processing techniques and motions is interpreted as reflecting cultural drift within this practice. Evidence for the grinding of ochre to produce small quantities of powder throughout the sequence is consistent with a use in symbolic activities for at least part of the ochre assemblage from Porc-Epic Cave.

Early pre-Hispanic use of indigo blue in Peru

Archaeological research has identified the use of cultivated cotton (Gossypium barbadense) in the ancient Andes dating back to at least 7800 years ago. Because of unusual circumstances of preservation, 6000-year-old cotton fabrics from the Preceramic site of Huaca Prieta on the north coast of Peru retained traces of a blue pigment that was analyzed and positively identified as an indigoid dye (indigotin), making it the earliest known use of indigo in the world, derived most likely from Indigofera spp. native to South America. This predates by ~1500 years the earliest reported use of indigo in the Old World, from Fifth Dynasty Egypt [ca. 4400 BP (before present)]. Indigo is one of the most valued and most globally widespread dyes of antiquity and of the present era (it being the blue of blue jeans).

Portuguese tin-glazed earthenware from the 17th century. Part 2: A spectroscopic characterization of pigments, glazes and pastes of the three main production centers

Sherds representative of the three Portuguese faience production centers of the 17th century - Lisbon, Coimbra and Vila Nova were studied with the use of mostly non-invasive spectroscopies, namely: ground state diffuse reflectance absorption (GSDR), micro-Raman, Fourier-transform infrared (FT-IR) and proton induced X-ray (PIXE) or X-ray fluorescence emission (XRF). X-ray diffraction (XRD) experiments were also performed. The obtained results evidence a clear similarity in the pastes of the pottery produced Vila Nova and some of the ceramic pastes from Lisbon, in accordance with documental sources that described the use of Lisbon clays by Vila Nova potters, at least since mid 17th century. Quartz and Gehlenite are the main components of the Lisbon's pastes, but differences between the ceramic pastes were detected pointing out to the use of several clay sources. The spectroscopic trend exhibited Coimbra's pottery is remarkably different, Quartz and Diopside being the major components of these pastes, enabling one to well define a pattern for these ceramic bodies. The blue pigment from the Lisbon samples is a cobalt oxide that exists in the silicate glassy matrix, which enables the formation of detectable cobalt silicate microcrystals in most productions of the second half of the 17th century. No micro-Raman cobalt blue signature could be detected in the Vila Nova and Coimbra blue glazes. This is in accordance with the lower kiln temperatures in these two production centers and with Co(2+) ions dispersed in the silicate matrix. In all cases the white glaze is obtained with the use of tin oxide. Hausmannite was detected as the manganese oxide mineral used to produce the purple glaze (wine color "vinoso") in Lisbon.

Raman spectroscopic study of "The Malatesta": a Renaissance painting?

Raman spectroscopic analysis of the pigments on an Italian painting described as a "Full Length Portrait of a Gentleman", known also as the "Malatesta", and attributed to the Renaissance period has established that these are consistent with the historical research provenance undertaken earlier. Evidence is found for the early 19th Century addition of chrome yellow to highlighted yellow ochre areas in comparison with a similar painting executed in 1801 by Sir Thomas Lawrence of John Kemble in the role of Hamlet, Prince of Denmark. The Raman data are novel in that no analytical studies have previously been made on this painting and reinforces the procedure whereby scientific analyses are accompanied by parallel historical research.

Pigment characterization of important golden age panel paintings of the 17th century

Samples were obtained from two world-famous 17th century panel paintings of the Gdańsk school of panting: 'Seven Acts of Charity' (1607, in St. Mary's Church in Gdańsk, Poland) by Anton Möller and 'Angelic Concert' (1611, in Diocesan Museum in Pelplin, Poland) by Hermann Han. Micro-Raman spectroscopy (MRS), optical microscopy (OM), and X-ray fluorescence (XRF) spectroscopy studies of the samples were performed to characterize the pigments present in the individual painting layers (a rich palette of white, black, blue, red, and yellow pigments) and the pictorial techniques used by the artists.

Analytical and microbiological characterization of paper samples exhibiting foxing stains

This work comprises the use of a multi-analytical approach combined with microbiological studies to characterize six paper samples, containing foxing stains, from the 20th century, regarding their cellulose matrix, fillers, and sizing materials, and to evaluate possible paper degradation that might have occurred during the foxing stains. Photography under different illuminations and optical microscopy were used for morphological characterization of the paper samples and foxing stains. Scanning electron microscopy coupled energy dispersive spectroscopy (SEM-EDS) was of particular importance for defining the presence of fiber disorder and disruption on the surface of some of the stains, and localized accumulations of mineral-like particles on the surface of others. SEM-EDS, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FT-IR), and energy dispersive X-ray fluorescence (EDXRF) were used for the identification of mineral fillers, whereas sizing agents were analyzed using ATR-FT-IR. EDXRF results showed that no differences, within the standard deviation, were found in iron and copper contents between the foxed and unfoxed areas. Fungi belonging to the genus Penicillium spp. were found in all the paper samples. Unfoxed areas presented lower contamination than the foxed areas.

An uncovered XIII century icon: particular use of organic pigments and gilding techniques highlighted by analytical methods

The restoration of a panel painting depicting a Madonna and Child listed as an unknown Tuscan artist of the nineteenth century, permitted the hidden original version, a XIII century Medieval icon to be uncovered. It is discovery provided the opportunity for an extensive in situ campaign of non-invasive analytical investigations by portable imaging and spectroscopic techniques (infrared, X-ray fluorescence and diffraction, UV-Vis absorption and emission), followed by aimed micro-destructive investigations (Raman and SEM-EDS). This approach permitted characterization of the original ground and paint layers by complementary techniques. Furthermore, this protocol allowed supplementary particularities of great interest to be highlighted. Namely, numerous original gilding techniques have been accentuated in diverse areas and include the use of surrogate gold (disulphur tin), orpiment as a further false gold and an area with an original silver rich layer. Moreover, pigments including azurite mixed with indigo have been non-invasively identified. Micro-invasive analyses also allowed the diagnosis of organic colorants, namely, an animal anthraquinone lake, kermes and an unusual vegetal chalcone pigment, possibly safflower. The identification of the latter is extremely rare as a painting pigment and has been identified using an innovative adaption to surface enhanced Raman techniques on a cross-section. The resulting data contributes new hypotheses to the historic and artistic knowledge of materials and techniques utilized in XIII century icon paintings and ultimately provides scientific technical support of the recent restoration.

Red, White and Black: Colors of Beauty, Tints of Health and Cosmetic Materials in Early Modern English Art Writing

Alongside Richard Haydocke's translation of Giovanni Paolo Lomazzo's treatise on painting (1598), the article examines concepts of color concerning cosmetics, painting and complexion as they relate to aesthetics, artistic and medical practice in the sixteenth and seventeenth centuries. Beginning with white and red as ideal colors of beauty in Agnolo Firenzuola's Discourse on the beauty of women (1541), the essay places color in relation to major issues in art, medicine and empiricism by discussing beauty as a quality of humoral theory and its colors as visual results of physiological processes. Challenging the relation of art and nature, gender and production, Lomazzo's account of complexion and Haydocke's additions on cosmetic practices and face-painting provide key passages that shed light on the relation of cosmetics colors, art writing and artistic practices at the convergence of the body, art and medicine in the context of the emerging English virtuosi around 1600.

The Saline Chymistry of Color in Seventeenth Century English Natural History

Before Newton's seminal work on the spectrum, seventeenth-century English natural philosophers such as Robert Boyle, Robert Hooke, Nehemliah Grew and Robert Plot attributed the phenomenon of color in the natural world to salts and saline chymistry. They rejected Aristotelian ideas that color was related to the object's hot and cold qualities, positing instead that saline principles governed color and color changes in flora, fauna and minerals. In our study, we also characterize to what extent chymistry was a basic analytical tool for seventeenth-century English natural historians.

Writing on Pigments in Natural History and Art Technology in Sixteenth-Century Germany and Switzerland

Renaissance painters used a number of inorganic color materials. The development of mineralogy as a discipline opened a new discourse on mineral pigments. Agricola and other naturalists were familiar with the contemporary writings on art technology, but their focus was different. Therefore, the exchange of knowledge between these two color worlds remained selective. One possible meeting point was the Kunstkammer where the study of natural objects and materials was combined with an interest in the manual execution of a painting.

Ulisse Aldrovandi's Color Sensibility: Natural History, Language and the Lay Color Practices of Renaissance Virtuosi

Famed for his collection of drawings of naturalia and his thoughts on the relationship between painting and natural knowledge, it now appears that the Bolognese naturalist Ulisse Aldrovandi (1522-1605) also pondered specifically color and pigments, compiling not only lists and diagrams of color terms but also a full-length unpublished manuscript entitled De coloribus or Trattato dei colori. Introducing these writings for the first time, this article portrays a scholar not so much interested in the materiality of pigment production, as in the cultural history of hues. It argues that these writings constituted an effort to build a language of color, in the sense both of a standard nomenclature of hues and of a lexicon, a dictionary of their denotations and connotations as documented in the literature of ancients and moderns. This language would serve the naturalist in his artistic patronage and his natural historical studies, where color was considered one of the most reliable signs for the correct identification of specimens, and a guarantee of accuracy in their illustration. Far from being an exception, Aldrovandi's 'color sensibility'spoke of that of his university-educated nature-loving peers.

Analysis of Red Pigments from the Neolithic sites of Çatalhöyük in Turkey and Sheikh-e Abad in Iran

Samples containing red pigment have been collected from two different archaeological sites dating to the Neolithic (Çatalhöyük in Turkey and Sheikh-e Abad in Iran) and have been analysed by a range of techniques. Sub-samples were examined by IR spectroscopy and X-ray diffraction, whilst thin sections were studied using optical polarising microscopy, synchrotron based IR microscopy and environmental scanning electron microscopy with energy dispersive X-ray analysis. Thin layers of red paint in a wall painting from Çatalhöyük were found to contain ochre (hematite and clay) as well as an unexpected component, grains of red and colourless obsidian, which have not been identified in any previous studies of the wall paintings at Çatalhöyük. These small grains of obsidian may have improved the reflective properties of the paint and made the artwork more vivid in the darkness of the buildings. Analysis of a roughly shaped ball of red sediment found on a possible working surface at Sheikh-e Abad revealed that the cause of the red colouring was the mineral hematite, which was probably from a source of terra rossa sediment in the local area. The results of this work suggest it is unlikely that this had been altered by the Neolithic people through mixing with other minerals.

An analytical Raman spectroscopic study of an important english oil painting of the 18th Century

An opportunity was afforded to analyse pigment specimens from an unrestored oil painting in the style of the English School of the mid-18th Century prior to conservation being undertaken. Raman spectroscopy was adopted to characterise the pigments and indicated the presence of a novel red pigment which was assigned to the complex chromium mineral, hemihedrite, in addition to other interesting materials found in combination. This is the first recorded identification of hemihedrite spectral signals in an art context in a range of mineral pigments that are otherwise typical of this period and some hypotheses are presented to explain its presence based on its occurrence with associated mineral pigments. It is suggested that the presence of powdered glass identified in certain areas of the painting enhanced the reflectivity of the pigment matrix.

Non-invasive investigation on a VI century purple codex from Brescia, Italy

Purple codices are among the most relevant and prestigious book productions of Late Antique and Medieval age. They usually contained texts from Holy Writings written with golden or silver inks on parchment dyed in a purple hue. According to the tradition, the colour of parchment was obtained by the well renowned Tyrian purple dye. From the material point of view, however, very little is known about the compounds actually used in the manufacture of these manuscripts. Presently, the information available is limited to the ancient art treatises, with very few diagnostic evidences supporting them and, moreover, none confirming the presence of Tyrian purple. It is more than apparent, then, the need to have at disposal larger and more complete information at the concern, in order to verify what came to us from the literary tradition only. In this study, preliminary results are presented from non-invasive investigation on a VI century purple codex, the so-called CodexBrixianus, held in the Biblioteca Civica Queriniana at Brescia (Italy). Analyses were carried out with XRF spectrometry, UV-visible diffuse reflectance spectrophotometry, molecular spectrofluorimetry and optical microscopy. The results suggest the hypothesis that Tyrian purple had been used as a minor component mixed with other less precious dyes such as folium or orchil.

Wall paintings studied using Raman spectroscopy: a comparative study between various assays of cross sections and external layers

This work describes a comparative study between in situ applications of portable Raman spectroscopy and direct laboratory measurements using micro-Raman spectroscopy on the surface of small samples and of cross sections. The study was performed using wall paintings from different sites of the Alcazar of Seville. Little information was obtained using a portable Raman spectrometer due to the presence of an acrylic polymer, calcium oxalate, calcite and gypsum that was formed or deposited on the surface. The pigments responsible for different colours, except cinnabar, were not detected by the micro-Raman spectroscopy study of the surface of small samples taken from the wall paintings due to the presence of surface contaminants. The pigments and plaster were characterised using cross sections. The black colour consisted of carbon black. The red layers were formed by cinnabar and white lead or by iron oxides. The green and white colours were composed of green emerald or atacamite and calcite, respectively. Pb3O4 has also been characterised. The white layers (plaster) located under the colour layers consisted of calcite, quartz and feldspars. The fresco technique was used to create the wall paintings. A wall painting located on a gypsum layer was also studied. The Naples yellow in this wall painting was not characterised due to the presence of glue and oils. This study showed the advantage of studying cross sections to completely characterise the pigments and plaster in the studied wall paintings.

Anatase: important industrial white pigment and date-marker for artwork

Barium sulfate, BaSO4, is shown by Raman microscopy to be readily identifiable in early (1920s) industrially produced anatase (TiO2) and thus, if present, may act as a date marker for early industrial anatase. Later processes (except that for producing Titanox B) did not involve usage of barium sulfate. The matter is relevant to the possible dating of certain artwork.

Micro-Raman analysis of the pigments on painted pottery figurines from two tombs of the Northern Wei Dynasty in Luoyang

The pigments on the painted pottery figurines from two tombs of Northern Wei Dynasty (AD 386-534) in Luoyang were analyzed by Raman microscopy. All the pigments were identified compared with the Raman spectra of standard pigments. The red pigments were identified as haematite, the blue pigment as lapis lazuli, the green pigment as malachite, the black pigment as carbon black and the white pigment as calcite. Similar pigments were used in the two tombs despite the pottery figurines were very different in artistic style. The use of lapis lazuli as blue pigment on Chinese painted pottery figurines was found for the first time. This pigment and the painted pottery figurine of Sogdians are of great archaeological significance because it demonstrated that the trade and cultural exchanges via the Silk Road had extended to Luoyang city in the Northern Wei Dynasty. The result also confirms that micro-Raman spectroscopy is a powerful analytical method for the identification of pigments on ancient artworks.

Ochres and earths: matrix and chromophores characterization of 19th and 20th century artist materials

The present paper describes the main results obtained from the characterization of a wide range of natural and synthetic ochre samples used in Portugal from the 19th to the 20th century, including powder and oil painting samples. The powder ochre samples came from several commercial distributors and from the collection of Joaquim Rodrigo (1912-1997), a leading Portuguese artist, particularly active during the sixties and seventies. The micro-samples of oil painting tubes came from the Museu Nacional de Arte Contemporânea-Museu do Chiado (National Museum of Contemporary Art-Chiado Museum) in Lisbon and were used by Columbano Bordalo Pinheiro (1857-1929), one of the most prominent naturalist Portuguese painters. These tubes were produced by the main 19th century colourmen: Winsor & Newton, Morin et Janet, Maison Merlin, and Lefranc. The samples have been studied using μ-Fourier Transform Infrared Spectroscopy (μ-FTIR), Raman microscopy, μ-Energy Dispersive X-ray fluorescence (μ-EDXRF), and X-ray diffraction (XRD). The analyzed ochres were found to be a mixture of several components: iron oxides and hydroxides in matrixes with kaolinite, gypsum and chalk. The results obtained allowed to identify and characterize the ochres according to their matrix and chromophores. The main chromophores where identified by Raman microscopy as being hematite, goethite and magnetite. The infrared analysis of the ochre samples allowed to divide them into groups, according to the composition of the matrix. It was possible to separate ochres containing kaolinite matrix and/or sulfate matrix from ochres where only iron oxides and/or hydroxides were detected. μ-EDXRF and Raman were the best techniques to identify umber, since the presence of elements such as manganese is characteristic of these pigments. μ-EDXRF also revealed the presence of significant amounts of arsenic in all Sienna tube paints.

Early synthetic dyes--a challenge for tandem mass spectrometry

The present study concerns identification of early yellow synthetic dyes from silk fibers taken from the 1930 spring color palette of the Lyon Dyers' Guild (La Chambre Syndicale des Teinturiers). The identification was based mainly on the electrospray ionization tandem mass spectrometry spectra obtained in the positive and negative ion modes. This technique was combined with high-performance liquid chromatography, which enabled separation of the analyzed compounds. Spectra registered for each of the examined synthetic dye allowed identification of their lost fragments. Moreover, isotopic profiles and exact measurements of m/z by using time of flight analyzer made possible to evaluate their elemental composition. In consequence, all obtained data, including UV-vis spectra, allowed to reconstruct molecular structures of examined colorants. Due to the lack of standards, the identification of the dyes was based only on the registration of fragment and quasi-molecular ions, what is rather uncommon in such analysis and means groping for the correct structure rather than proving signal identity by comparison with standards. Depending on substituents present in dye molecules, the lost fragments of the examined compounds involved SO(2), NO(•), NO(2)(•), CH(4), C(2)H(4), C(2)H(5)(•), C(2)H(6), CH(2)=N-CH(3), (CH(3))(2)NH, CH(2)= NH, CH(3)-NH(2), as well as CO and CO(2). The performed study led to identification of various colorants: rhodamine 6 G, rhodamine B, malachite green, quinoline yellow, picric acid and acetoquinone yellow 5JZ.

Tyrian purple: the first four thousand years

Some of the long history ofshellfish purple is recounted Understanding how the dye is produced from molluscs, the composition of the pigment and the chemistry involved has only been achieved as a result of the advances in analytical chemistry in the twentieth century, but some mysteries remain. Other diverse aspects such as the taste of the molluscs, the actual colour of the dye, the smell associated with the production and even the application in photography contribute to the fascination of the subject.

Pierre-Joseph Macquer an eighteenth-century artisanal-scientific expert

Pierre-Joseph Macquer (1718-1784) is well known as one of the major chemists in the eighteenth century as a theoretician and a teacher. He is also known for his works on dyeing. This paper presents a new face of Macquer. He proposed a theory on mordants in dyeing as early as 1775. Besides his activity at the Académie des sciences, he played an important role in Government as the commissioner of dyeing from 1766 where he established close links with artisan inventors. Académicien chimiste at the royal Manufactory of Sèvres from 1757, he was also the inventor of French porcelain. His notebooks show his organization, method, courage, passion and obstinacy in the search for the paste for hard porcelain. He also proposed an interpretation of its formation. Macquer was both a theoretician and a practical expert in dyeing as well as in porcelain making. He managed to bridge the gap between science and art.

Analytical Raman spectroscopic discrimination between yellow pigments of the Renaissance

The Renaissance represented a major advance in painting techniques, subject matter, artistic style and the use of pigments and pigment mixtures. However, most pigments in general use were still mineral-based as most organic dyes were believed to be fugitive; the historical study of artists' palettes and recipes has assumed importance for the attribution of art works to the Renaissance period. Although the application of diagnostic elemental and molecular spectroscopic techniques play vital and complementary roles in the analysis of art works, elemental techniques alone cannot definitively provide the data needed for pigment identification. The advantages and limitations of Raman spectroscopy for the definitive diagnostic characterisation of yellow pigments that were in use during the Renaissance is demonstrated here in consideration of heavy metal oxides and sulphides; these data will be compared with those obtained from analyses of synthetic yellow pigments that were available during the eighteenth and nineteenth Centuries which could have been used in unrecorded restorations of Renaissance paintings.

The use of a multi-method approach to identify the pigments in the 12th century manuscript Liber Floridus

A selection of illuminations of the 12th century manuscript Liber Floridus was analysed with Raman spectroscopy (in situ and laboratory measurements), X-ray fluorescence spectroscopy, UV-fluorescence photography and infrared reflectography (IRR). The aim of this study is to determine the pigments used, in order to search for anachronisms. Using a combination of Raman spectroscopy (molecular information) and X-ray fluorescence spectroscopy (elemental information) following pigments could be identified: ultramarine (Na(8-10)Al(6)Si(6)O(24)S(2-4)), azurite (2CuCO(3)·Cu(OH)(2)), caput mortuum (Fe(2)O(3)), vermilion (HgS), orpiment (As(2)S(3)) and lead white (2PbCO(3)·Pb(OH)(2)). Moreover, two synthetic red pigments, PR4 and PR176, and a degradation product, gypsum (CaSO(4)·2H(2)O), were present in the manuscript. To establish the origin of the modern materials UV-fluorescence photography was used. Infrared reflectography (IRR) was applied to visualise the underdrawing of the investigated folios.

J. M. Despréaux' lichens from the Canary Islands and West Africa: an account of a 19th century collection found in an English archive

This is an historical and descriptive account of 28 herbarium specimens, 27 lichens and an alga, found in the archives of Charles Chalcraft, a descendant of the Bedford family, who were dye manufacturers in Leeds, England, in the 19th century. The lichens comprise 13 different morphotypes collected in the Canary Islands and West Africa by the French botanist J. M. Despréaux between 1833 and 1839. The collections include samples of "Roccella fuciformis", "R. phycopsis" and "R. tinctoria" (including the fertile morphotype "R. canariensis"), "Ramalina crispatula" and "R. cupularis", two distinct morphotypes of "Sticta", "S. canariensis" and "S. dufouri", "Physconia enteroxantha", "Pseudevernia furfuracea var. ceratea" and "Pseudocyphellaria argyracea". The herbarium also includes authentic material of "Parmotrema tinctorum" and a probable syntype of "Seirophora scorigena". Most of these species are known as a source of the purple dye orchil, which was used to dye silk and wool.

Greek alchemists at work: 'alchemical laboratory' in the Greco-Roman Egypt

The paper focuses on the alchemical laboratory of ancient Greco-Egyptian alchemists, by taking into account especially the earliest alchemical texts (both in the Greek and in the Syriac tradition), ascribed to Pseudo-Democritus, Maria the Jewish and Zosimus. The first part analyzes the possible relationships between the workshops of Egyptian craftsmen (first of all, dyers, metals workers and glass workers) and the activity of the alchemists. The second part gives a general overview on the alchemical instruments described in the Corpus alchemicum.

[Corneal tatoo--art or science?]

The permanent colouring of disfigured corneal scars is known for almost 200 years. Because of improvement in surgical reconstructive techniques, corneal tattoing is used today only with a restricted group on carefully chosen patients, and merely for esthetique reasons.

Investigation of Livingstone's curious point

The explorer and missionary David Livingstone was identified after death by the appearances of his humerus which had been damaged in an encounter with a lion. In his writings Livingstone suggested that the consequences of the lion's attack were not as bad as he might have expected. He wondered if this was due to the fact that he was wearing a tartan jacket when he was attacked and suggested that this curious point should be investigated. This paper looks at some of the dyes used in tartans of the time and investigates their effect on the bacteria that might be present in the mouths of lions.

Simultaneous identification of natural dyes in the collection of drawings and maps from The Royal Chancellery Archives in Granada (Spain) by CE

A simple and rapid capillary electrophoretic method with UV detection (CE-UV) has been developed for the identification of five natural dyes namely, carmine, indigo, saffron, gamboge and Rubia tinctoria root. The separation was performed in a fused-silica capillary of 64.5 cm length and 50 microm id. The running buffer was 40 mM sodium tetraborate buffer solution (pH 9.25). The applied potential was 30 kV, the temperature was 25 degrees C and detections were performed at 196, 232, 252, 300 and 356 nm. The injections were under pressure of 50 mbar during 13 s. The method was applied to the identification of carminic acid, gambogic acid, crocetin, indigotin, alizarin and purpurin in the collection of drawings and maps at the Royal Chancellery Archives in Granada (Spain). The method was validated by using HPLC as a reference method.

[Dyes, indispensable tools for the 19th century's biologic and therapeutic revolution]

Born from growing organic chemistry laboratories, dyes were extensively used par textile industry before to be applied in field of biology and therapeutics. Besides their interest for diagnostic techniques due to cell visualization (Virchow, Papanicolaou), dyes allowed scientists to propose scientific hypothesis founding, in conjunction with new microscopy tools, modern basis for biology : tissue constitution, cellular and sub cellular structure, s.o. One of the brightest illustrations of these progresses is the birth of neuronal theory which due to silver print of brain tissue allowed to see intimacy of cerebral structures et propose an operating scheme (Golgi, Cajal). Therapeutic progresses born from dyes chemistry are multiple. First concentrated on the research of antimalarial drugs (Ehrlich) following the use of methylene blue, then generally, anti-infectious drugs, they gave birth to various chimiotherapeutic families: antiseptics, antiparasitic drugs, antibacterial, among which one of the most spectacular illustrations remain sulphonamides preparation.

[Natural dyes and dyeing from the XVIIth century to the birth of synthetic dyes]

After historical considerations on the state and evolution of French dyeing industry in the end of the XVIIth century to the beginning of XIXth, we find this presentation a résumé of the different states of tissues dyeing. We easily note that the techniques of dyeing. We easily note that the techniques of dyeing were very brought forward the end of the XVIIIth century before that synthetic dyes appeared in the second half of the XIXth century.

The invention of blue and purple pigments in ancient times

This tutorial review examines manmade blue and purple pigments appearing in antiquity. They were obtained by chemical synthesis from mineral starting materials and refer to chemical compounds: Egyptian Blue (CaCuSi4O10), Han Blue (BaCuSi4O10) and Han Purple (BaCuSi2O6), Maya Blue (x.indigo.(Mg,Al)4Si8(O,OH,H2O)24) and Ultramarine Blue (Na,Ca)8(AlSiO12)(S, SO4,Cl). The Egyptian and Chinese copper-based pigments are assumed to have been developed independently and are presumably an outcome of the historical developments in glazing techniques. A technology transfer from Egypt into China cannot be fully excluded but, based on the facts acquired up to now, looks less probable.

[The black reaction: an ante litteram "cognitive" biotechnology]

The black reaction, also known nowadays as "Golgi staining" or "Golgi impregnation", paved the way to the development of modern neuroscience at the end of XIX century. By this staining, the silhouette of the nerve cell appears in all its morphological complexity with all its ramifications, which could be followed and analyzed even at a great distance from the cell body. However the reaction has been fundamental for discoveries in several other areas of biomedical research: cytology, myology, bacteriology. With the aid of the black reaction, for example, it was possible to observe: the Golgi apparatus, the T system related to the function of the sarcoplasmatic reticulum, the Müller-Golgi canaliculi of the peptic glands and many more; this wide and various success is due to its character of morphological amplification of fine structures. In spite of its still controversial biochemical nature, the black reaction has been an unavoidable versatile tool in different areas of biology, so we propose to consider this method as an ante litteram "cognitive" biotechnology.

[The history of tooth dyeing]

While tooth dyeing is a disappearing custom, the pharmaceutical benefits of paan in India are now being studied for other reasons. The oral carcinogenicity of betel nuts, the traditional ingredient in paan, however, has been causing paan users to replace betel with canari or lime. As a consequence of this trend, the pharmaceutical interest of paan is no longer in betel, but in the health-promoting properties of Uncaria gambir. This article has been prepared as an interim record of the progress of the author's research into this field, and was presented in the December 2006 meeting of the [symbol see text].

Sampling and identification of natural dyes in historical maps and drawings by liquid chromatography with diode-array detection

A simple and rapid liquid chromatographic with diode-array UV-vis spectrophotometric detection (HPLC-DAD) method for identification of natural dyes has been developed. Chromatographic retention of carminic acid, indigotin, crocetin, gambogic acid, alizarin and purpurin has been studied. The mobile phase consisted of 40 mM SDS-10 mM phosphate buffer solution (pH 2.3)-0.1% TFA (eluent A) and acetonitrile (eluent B) using a programmed gradient (5% B to 95% B). Analyses were carried out on a Phenomenex, Luna 5u NH2 100(a) column (250 mm x 4.60 mm i.d., 5 microm particle) and the operating conditions were: 0.6 ml min(-1) flow rate, 20 microl volume injection and 35 degrees C column temperature. Extracts of samples of natural dyes taken from historical maps belonging to The Royal Chancellery Archives in Granada were successfully analyzed using the proposed method including a new technique for sampling.

[Injectable dyes: more than 70 years of therapeutic usage of dyes]

Synthetic dyes were first discovered at the end of the XVIIIth century (picric acid by Woulfe in 1771) and during the first part of the XIXth century: rosolic acid (Runge, 1834), mauvein (Perkin, 1856), but their development was major at the end of the XIXth century. Their therapeutic use was really starting at the beginning of the XXth century, mainly by local and oral route. It is only in the 1930's that parenteral route of administration was actually developed: methylene blue, methyl violet are some examples that were used for leprosy and filariasis, respectively. After the 2nd world war, one can observe a rapid decrease of the therapeutic use of dyes by intravenous route. Only a few dyes are still used today, such as patent blue V or fluorescein, as drugs for diagnostic use.

Liquid chromatography determination of natural dyes in extracts from historical Scottish textiles excavated from peat bogs

Textiles excavated from Scottish sites belonging now to the collections of the National Museums of Scotland, including seventeenth century textiles from peat bogs in the Scottish Highlands and Islands, were selected for analysis by high performance liquid chromatography with photodiode array detection (PDA HPLC) to detect whether any dyes remained and, if so, to identify their biological sources. Dye components were identified in 36 of the 81 samples analysed. Although it was not possible to identify the exact sources of the dyestuffs because of the wide-spread occurrence of these natural dyes components, the study has shown that textiles previously not thought to have been coloured had detectable traces of dye. Before the historical textiles were analyzed, an improved extraction procedure that combined the routine acid hydrolysis method with one using dimethylformamide (DMF) was applied. The DMF method enabled increased recovery of major flavonoid and anthraquinoid compounds, and very high efficiency of recovery of indigotin even in textiles with no colour visible, thereby complementing the acid hydrolysis method already in use. Extracts from historical thread samples were analysed by PDA HPLC using a reversed-phase gradient system comprising of a C18 column (150 mm x 4.6 mm i.d., 25 +/- 1 degrees C) with water, methanol and o-phosphoric acid at an eluent flow rate of 1.2 ml/min. A preliminary investigation to improve the detection limits further for a selection of natural dyes was made by comparing results from the 4.6mm internal diameter (i.d.) column with a narrow bore C18 column (2.1 mm i.d.). An increase in the detector response was observed for narrow-bore column proving its possibility of enhancement of sensitivity.

The long history of hematoxylin

Hematoxylin is a naturally occurring chemical used as the basis of a dye in laboratories throughout the world to stain nuclei in microscope slide preparations. This chemical is extracted from the logwood tree Hematoxylon campechianum and was discovered by Spanish explorers to the Yucatan in 1502. A vigorous trade soon developed related to growing and preparing hematoxylin for use in dyeing fabrics in Europe. In the mid 1800s, amateur microscopists first used hematoxylin to stain cellular components. Later scientists developed a wide range of techniques to demonstrate different cellular components. Hematoxylin remains the most popular nuclear stain in histology. This paper briefly describes the history of hematoxylin production and use in histology.

[Is Chevreul accountable for the backward state of synthetic dyes in France?]

Head of dying at the Manufacture des Gobelins, Chevreul presided over the French Council of Arts and Manufactures and took part in the selection committees of universal exhibitions. He was accused of lacking judgement against synthetic dyes. His correspondence with dyers shows other more determinant brakes as legislative and economic ones, against which scientist, without political power, could not act efficiently.