Artist Pigments

de Pedralbes de Barcelona és una petita estança de només vint metres quadrats de superfície, la decoració de la qual fou encarregada al taller de Ferrer Bassa l’any 1346. Malgrat les seves dimensions reduïdes, en conjunt suma prop de cent metres quadrats de superfície pictòrica, uns setanta-cinc dels quals corresponen als murals que omplen els paraments amb escenes de la Passió de Crist, els Goigs de la Verge, el Judici Final i la Salvació de les Ànimes, com també amb diverses figures de sants. La superfície restant és la decoració de l’embigat que representa la volta celeste. La pintura mural s’estructura en registres delimitats per sanefes amb motius geomètrics. Als registres central i superior es desenvolupen les diverses escenes emmarcades a dalt i a baix per una arquitectura simulada de plafons de marbre fingits.1 Tots aquests elements accentuen el marcat italianisme del cicle pictòric que vincula Barcelona i la Corona d’Aragó amb les innovacions que neixen a les ciutats toscan...

Few research studies from the early seventies reported the use of far infrared (FIR) spectroscopy and its analytical potential. Especially in the field of cultural heritage, particular attention has not been given to this technique because of its destructive character; however, this can be overcome by employing Raman microscopy. Provided that enough quantity of the sample is available, FIR spectroscopy may represent a useful analytical method in the case of inorganic compounds that are not active in the mid infrared region and, because of the fluorescent effect produced by the organic media, not detectable even by Raman spectroscopy. In this article, the application of FIR spectroscopy has been applied for the characterisation of several inorganic pigments. A preparation method based on the use of polyethylene has been developed that allows analyses with moderate quantity of sample (0.5-1.5 mg). The data obtained have been compared with Raman results with the aim to build a common database. Some applications on real case studies are presented and discussed.

Few research studies from the early seventies reported the use of far infrared (FIR) spectroscopy and its analytical potential. Especially in the field of cultural heritage, particular attention has not been given to this technique because of its destructive character; however, this can be overcome by employing Raman microscopy. Provided that enough quantity of the sample is available, FIR spectroscopy may represent a useful analytical method in the case of inorganic compounds that are not active in the mid infrared region and, because of the fluorescent effect produced by the organic media, not detectable even by Raman spectroscopy. In this article, the application of FIR spectroscopy has been applied for the characterisation of several inorganic pigments. A preparation method based on the use of polyethylene has been developed that allows analyses with moderate quantity of sample (0.5-1.5 mg). The data obtained have been compared with Raman results with the aim to build a common database. Some applications on real case studies are presented and discussed.

Indian yellow has always been a mysterious pigment. In 1883, an eye-witness account of its production described it as a urinary sediment from cows fed a mango leaves rich diet; this same account describes a set of manufacturing materials and samples sent to the Royal Botanic Gardens, Kew (England). Most of these original materials were recovered in 2016 from the Economic Botany Collection at Kew, and analyzed alongside known reference materials, to characterize the pigment materials, and to search for evidence of an animal origin. Component characterization and identification was performed using py(TMAH)-GC-MS, LC-MS, FTIR, Raman Spectroscopy, SEM-EDS, UVA-induced visible fluorescence, and polarized light microscopy. All the materials were shown to contain variable ratios of reported components of Indian yellow (euxanthic acid, euxanthone, and a sulfo-derivative of euxanthone), and some presented hippuric acid, a ruminant metabolite found in urine. This is the first substantial link between animal urine and the pigment Indian yellow. When possible, the interior and exterior of the pigment-balls were characterized, and a higher amount of euxanthone was consistently detected on the exposed exterior of the ball. It is proposed, that euxanthone may be a chemical marker for the degradation of Indian yellow. A laboratory prepared euxanthone was used for comparison; this paper presents the characterization data for euxanthone, much of which is the first time it has been reported in the literature.

Few research studies from the early seventies reported the use of far infrared (FIR) spectroscopy and its analytical potential. Especially in the field of cultural heritage, particular attention has not been given to this technique because of its destructive character; however, this can be overcome by employing Raman microscopy. Provided that enough quantity of the sample is available, FIR spectroscopy may represent a useful analytical method in the case of inorganic compounds that are not active in the mid infrared region and, because of the fluorescent effect produced by the organic media, not detectable even by Raman spectroscopy. In this article, the application of FIR spectroscopy has been applied for the characterisation of several inorganic pigments. A preparation method based on the use of polyethylene has been developed that allows analyses with moderate quantity of sample (0.5-1.5 mg). The data obtained have been compared with Raman results with the aim to build a common database. Some applications on real case studies are presented and discussed.

Few research studies from the early seventies reported the use of far infrared (FIR) spectroscopy and its analytical potential. Especially in the field of cultural heritage, particular attention has not been given to this technique because of its destructive character; however, this can be overcome by employing Raman microscopy. Provided that enough quantity of the sample is available, FIR spectroscopy may represent a useful analytical method in the case of inorganic compounds that are not active in the mid infrared region and, because of the fluorescent effect produced by the organic media, not detectable even by Raman spectroscopy. In this article, the application of FIR spectroscopy has been applied for the characterisation of several inorganic pigments. A preparation method based on the use of polyethylene has been developed that allows analyses with moderate quantity of sample (0.5-1.5 mg). The data obtained have been compared with Raman results with the aim to build a common database. Some applications on real case studies are presented and discussed.

This contribution focuses on the study and preservation of 14 out of 35 powdery pigments in original paper bags. These are part of the artist materials reference collection at the Munch Museum in Oslo. The challenge of this study consists in the lack of information about the year of purchase of the pigments and its content. Some information is provided by the manufacturer's handwritten notes, some of them are, however, unreadable and a few bags have no information, nor on manufacturer or on its content. Munch has used at least four known Oslo based manufactures and some of the information from these paper bags could help giving at least some dating. Some relate to the name change of the city, from Kristiania to Oslo in 1925. Other information relates to the manufacturer's history, writing style, logos, addresses and telephone numbers. So far, the dating is the following: 1900-1925, 1922-1925 or after 1922. Some of the original paper bags, were in a very poor state and some containing highly hazardous pigments. The damages were significant and some relates to previous handling; such as tears, others had large, corroded holes on bottom or sides. All these required conservations to enable further storage of the pigments and to prevent additional damage from handling. Several bags were also stained with its powdery pigment which compromised the conservation by choosing a non-aqueous treatment. Heat activated adhesive with BEVA® 371 film lined with hand-colored Japanese tissues was applied for bridging of tears and infills of holes. 14 different pigments (of white, yellow, red, blue and green colours) were analyzed using ATR-FTIR, pXRF, SEM-EDS, XRD, Raman spectroscopy and synchrotron-based far-infrared spectroscopy for understanding their chemical composition. The analytical characterization shows a palette of pigments and lakes as one could expect from the first half of 20 th century. Apart from common pigments and extenders such as chrome yellow, cadmium yellow, Prussian blue, barium sulfate and others, an amorphous silicate was found which is assumed to create texture effects or is the raw material for production of waterglass. One of the cadmium yellow samples has a remarkable content of cadmium carbonate which may be related to the production method and/or the degradation of cadmium yellow. In one sample a hydrated calcium carbonate occurs. This study opens future research regarding this artist's collection, adding new knowledge about Munch's own use of art materials but also in general on modern paint materials.

Few research studies from the early seventies reported the use of far infrared (FIR) spectroscopy and its analytical potential. Especially in the field of cultural heritage, particular attention has not been given to this technique because of its destructive character; however, this can be overcome by employing Raman microscopy. Provided that enough quantity of the sample is available, FIR spectroscopy may represent a useful analytical method in the case of inorganic compounds that are not active in the mid infrared region and, because of the fluorescent effect produced by the organic media, not detectable even by Raman spectroscopy. In this article, the application of FIR spectroscopy has been applied for the characterisation of several inorganic pigments. A preparation method based on the use of polyethylene has been developed that allows analyses with moderate quantity of sample (0.5-1.5 mg). The data obtained have been compared with Raman results with the aim to build a common database. Some applications on real case studies are presented and discussed.

Zinc orange is a rare and relatively undocumented pigment. Mention of this pigment in the literature indicated its short lived availability to artists in the nineteenth century and that it is unstable, but does not address any specific issues related to its degradation. The synthesis of the original pigment is discussed. In addition, a full characterization of the pigment is presented including XRF, FTIR, Raman and optical microscopy. Research into its degradation mechanisms was also undertaken, and the light fastness of the pigment is presented.

Maya Blue is an unusual blue pigment consisting of a clay-organic complex of indigo and the unusual clay mineral palygorskite (also called attapulgite). Used on pottery, sculpture, and murals from the Preclassic to Late Colonial periods largely in Mesoamerica, blue was the color of sacrifice and ritual. Did the palygorskite used to make Maya Blue come from a restricted source in Yucatán like Shepard, Arnold, Arnold and Bohor believed, or from widespread sources like Littmann argued? This report presents the results of a pilot study comparing INAA and LA-ICP-MS analysis of 33 palygorskite samples collected from different parts of the Maya area. These data reveal that it is possible to discriminate mineral source locations, and that it should be possible to determine whether the palygorskite used to make Maya Blue came from widespread sources or was traded widely from one or a few sources. Consideration of contextual information such as agency, landscape and language suggest that the ...

Maya Blue is an unusual blue pigment consisting of a clay-organic complex of indigo and the unusual clay mineral palygorskite (also called attapulgite). Used on pottery, sculpture, and murals from the Preclassic to Late Colonial periods largely in Mesoamerica, blue was the color of sacrifice and ritual. Did the palygorskite used to make Maya Blue come from a restricted source in Yucatán like Shepard, Arnold, Arnold and Bohor believed, or from widespread sources like Littmann argued? This report presents the results of a pilot study comparing INAA and LA-ICP-MS analysis of 33 palygorskite samples collected from different parts of the Maya area. These data reveal that it is possible to discriminate mineral source locations, and that it should be possible to determine whether the palygorskite used to make Maya Blue came from widespread sources or was traded widely from one or a few sources. Consideration of contextual information such as agency, landscape and language suggest that the ...

Zinc orange is a rare and relatively undocumented pigment. Mention of this pigment in the literature indicated its short lived availability to artists in the nineteenth century and that it is unstable, but does not address any specific issues related to its degradation. The synthesis of the original pigment is discussed. In addition, a full characterization of the pigment is presented including XRF, FTIR, Raman and optical microscopy. Research into its degradation mechanisms was also undertaken, and the light fastness of the pigment is presented.

Zinc orange is a rare and generally undocumented artists’ pigment lost in the history. Only one sentence is devoted to it in George Field’s 1869 Chromatography: “…when hydrochloric acid and zinc are made to act on nitro-prusside of sodium, a corresponding zinc compound is formed of a deep orange colour, slightly soluble in water, and not permanent”1.  The focus of this project was to investigate how zinc orange was manufactured, as described by Field’s Chromatography. Various ratios of the listed ingredients metallic zinc, hydrochloric acid, and sodium nitroprusside were attempted. Different methods of processing the resulting pigments were tested, including heating, grinding, and washing. Additionally, artificial aging was performed to test the light stability of the pigment.

In modern art we can see that artists are breaking with traditional techniques. New materials like sponge, polyester, sand, etc. are being used. This causes a lot of new problems in the (preventive) conservation of works containing these materials. Every material needs to be researched individually so the exact intention of the artist can be preserved for a (relatively) long period. My research is about very recent materials: fluorescent pigments and paints. These only started to be used by artists from the 60’s. That's why there is not much information about their aging and ways to (preventively) conserve them. A lot of fluorescent paintings are meant to be shown under UV-light. If a fluorescent painting has damage and needs to be retouched there is a big esthetical problem. The retouched damage is visible under UV-light. The title of this thesis is born out of this last problem: Conservation problems with paintings containing fluorescent layers of paint. The first topic of research for this thesis concerns the composition of these different sorts of paint and pigments. Afterwards, the causes of damage resulting from UV-light –and other factors- were thoroughly analyzed. Finally, a possible remedy is being proposed.

Los avances en la tecnología de los materiales se han ampliado la variedad de materiales disponibles para el artista, la creación de nuevas posibilidades para la pintura mural. Las reinterpretaciones de algunas viejas tecnologías también indican las posibilidades innovadoras. El pasado está involucrado en un diálogo con el futuro. Las innovaciones en los materiales relacionados con la nano-tecnología incluyen pigmentos híbridos orgánicos/ inorgánicos, cristales fotónicos coloidales y recubrimientos anti-graffiti. Un aumento de la información sobre los materiales puede llevar en muchas direcciones. Una de ellas es la idea de la pintura mural como conservación. En un proyecto reciente, usé una resina acrílica hecho para la conservación de la albañilería como aglutinante en los pigmentos minerales. La resina aumentó la penetración de partículas de pigmento y ayudó a consolidar el ladrillo antiguo. Las antiguas tecnologías a menudo muestran el camino para las nuevas orientaciones en la pintura mural y la conservación. Las prácticas de pintura al fresco se relacionan con temas de actualidad como la sostenibilidad y la conservación del patrimonio cultural. El uso de cal tiene ventajas medioambientales, tales como costos energéticos más
bajos en la producción y el transporte. La pintura al fresco refuerza los conocimientos tradicionales sobre el uso
de cal y las habilidades con el yeso, que a la vez, apoya los esfuerzos para conservar el patrimonio arquitectónico.
Uno de los objetivos a largo plazo es crear un modelo para un enfoque integrado a la conservación del patrimonio inmaterial, cultural y natural.

Advances in technology of materials have broadened the variety of materials available to the artist, creating new possibilities for mural painting. Reinterpretations of some old technologies point towards innovative possibilities as well.
The past is involved in a dialogue with the future.

Innovations in materials related to nanotechnology include organic/inorganic hybrid pigments, colloidal photonic crystals
and anti-graffiti coatings. An increase in information about materials can lead in many directions. One is the idea of mural painting as conservation. In a recent project, I used an acrylic resin made for conservation of masonry as a binder for mineral pigments. The resin increased the penetration of pigment particles and helped to consolidate old brick. Old technologies often show the way for new directions in wall painting and conservation. Fresco painting practices relate to current issues of sustainability and conservation of cultural heritage. The use of lime has environmental advantages, such as lower energy costs in production and transportation. Fresco painting reinforces traditional knowledge about lime use and plastering skills, which in turn supports efforts to conserve architectural heritage. A long term goal is to create a model for an integrated approach to the conservation of intangible, cultural and natural heritage.

Paraules clau
Blau maia, arqueomimetisme, pintura al fresc, pigments, morter de calç.

Maya Blue is an unusual blue pigment consisting of a clay-organic complex of indigo and the unusual clay mineral palygorskite (also called attapulgite). Used on pottery, sculpture and murals from the Preclassic to the Late Colonial Period largely in Mesoamerica, blue was the color of sacrifice and ritual. Did the palygorskite used to make Maya Blue come from a restricted source in Yucatán like Shepard, Arnold, Arnold and Bohor believed, or did it come from widespread sources like Littmann argued? This article reports the results of a pilot study comparing INAA and LA-ICP-MS analysis of 33 samples of palygorskite collected from different parts of the Maya area. These data reveal that it is possible to discriminate source locations of the mineral, and that it should be possible to determine whether the palygorskite used to make Maya Blue came from widespread sources or was traded widely from a single or small number of sources.

Maya Blue is a colour that is more than a pigment; it had roles in status, ritual and performance, being daubed onto pots and people before sacrifice. Here researchers use experimental and historical evidence to discover how it was made, including direct scientific analysis of Maya Blue on a pot thrown into the sacred well at Chichén Itzá. The results indicate that the formation of the color was actually part of the ritual.