Gesso Section A
Gesso (Italian pronunciation: [ˈdʒɛsːo] "chalk," from the Latin: gypsum, from Greek: γύψος) is a white paint mixture consisting of a binder mixed with chalk, gypsum, pigment, or any combination of these. It is used in artwork as a preparation for any number of substrates such as wood panels, canvas and sculpture as a base for paint and other materials that are applied over it.
"Gesso", also known "glue gesso" or "Italian gesso" is a traditional mix of an animal glue binder (usually rabbit-skin glue), chalk, and white pigment, used to coat rigid surfaces such as wooden painting panels as an absorbent primer coat substrate for painting. The colour of gesso was usually white or off-white. Its absorbency makes it work with all painting media, including water-based media, different types of tempera, and oil paint. It is also used as a base on three-dimensional surfaces for the application of paint or gold leaf. Mixing and applying it is an art form in itself since it is usually applied in 10 or more extremely thin layers. It is a permanent and brilliant white substrate used on wood, masonite and other surfaces. The standard hide glue mixture is rather brittle and susceptible to cracking, thus making it suitable for rigid surfaces only. For priming flexible canvas, an emulsion of gesso and linseed oil, also called "half-chalk ground", is used. In geology, the Italian "gesso" corresponds to the English "gypsum", as it is a calcium sulfate mineral (CaSO4·2H2O).
Modern "acrylic gesso" is a widely used ground that is a combination of calcium carbonate with an acrylic polymer medium latex, a pigment and other chemicals that ensure flexibility, and increase archival life. It is technically not gesso at all and its non-absorbent acrylic polymer base makes it incompatible with media that require traditional gesso such as egg tempera. It is sold premixed for both sizing and priming panels and flexible canvas for painting. While it does contain calcium carbonate (CaCO3) to increase the absorbency of the primer coat, titanium dioxide or "titanium white" is often added as the whitening agent. This allows gesso to remain flexible enough to use on canvas.
Acrylic gesso can be colored, either commercially by replacing the titanium white with another pigment, such as carbon black, or by the artist directly, with the addition of an acrylic paint. Acrylic gesso can be odorous, due to the presence of ammonia and/or formaldehyde, which are added in small amounts as preservatives. Art supply manufacturers market canvases pre-primed with gesso.
The Painter's Handbook notes a problem with using oil paints over an acrylic gesso ground instead of a traditional oil ground, citing a mismatch in flexibility over time that could cause the oil paint to delaminate.
Soy-based gesso is a low emitting bio-based gesso made from recycled soy content. Soy gesso is made with new bio-based dispersion technology that uses a soy ester with a modified soy-vegetable oil acrylic. The surface is similar to acrylic gesso, but is not a solid acrylic. Soy gesso is made using a thin film of a modified acrylic and the soy ester. The penetration and adhesion of the soy ester to the substrate and the thin film of modified acrylic may have advantages in creating a surface that allows a physical bond between the gesso and the oil paint. In addition, the thinner modified acrylic film is more resistant to cracking than a solid acrylic gesso.
Gesso is also used by sculptors to prepare the shape of the final sculpture (fused bronze) or directly as a material for sculpting. Gesso can also be used as a layer between sculptured wood and gold leaf. In this case, a layer of red shellac called "assiette" is used to cover the gesso before applying the gold. A collection of gesso sculptures is properly called a gypsotheque.
Gesso Section B - Cennini's Gesso and Historical use of Gesso
basic lead carbonate
CAS number 1319-46-6
Molecular formula 2PbCO3·Pb(OH)2
Molar mass 775.633 g/mol
Appearance white powder
Main hazards lead poisoning
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Color pigments used on the warship Vasa, with white lead second left, bottom shelf.
White lead is the chemical compound (2PbCO3·Pb(OH)2). It is a complex chemical compound, containing both a carbonate and a hydroxide portion. White lead occurs naturally as a mineral, in which context it is known as hydrocerussite, a hydrate of cerussite. It was formerly used as an ingredient for lead paint and a cosmetic called Venetian Ceruse, because its opaque quality and the satiny smooth mixture it made with driable oils it made a good pigment. However, it tended to cause lead poisoning, and its use has been banned in most countries.
White lead compounds were also used as lubricants for bearings and in machine shops, especially between work being turned in a lathe and a dead center.
The commonly known Dutch method for the preparation of cerussite was described as early as Theophrastus of Eresos (ca. 300 B.C.), in his brief work on rocks or minerals, On Stones or History of Stones. His directions for the process were repeated throughout history by many authors of chemical and alchemical literature. The uses of cerussa were described as an external medication and as a pigment.
Clifford Dyer Holley quotes from Theophrastus' History of Stones as follows, in his book The Lead and Zinc Pigments.
Lead is placed in earthen vessels over sharp vinegar, and after it has acquired some thickness of a sort of rust, which it commonly does in about ten days, they open the vessels and scrape it off, as it were, in a sort of foulness; they then place the lead over vinegar again, repeating over and over again the same method of scraping it till it has wholly dissolved. What has been scraped off they then beat to powder and boil for a long time, and what at last subsides to the bottom of the vessel is ceruse
Later descriptions of the Dutch process involved casting metallic lead as thin buckles and corroded with acetic acid in the presence of carbon dioxide. This was done by placing them over pots with a little vinegar (which contains acetic acid). These were stacked up and covered with a mixture of decaying dung and spent tanner's bark, which supplied the CO2, and left for six to fourteen weeks, by which time the blue-grey lead had corroded to white lead. The pots were then taken to a separating table where scraping and pounding removed the white lead from the buckles. The powder was then dried and packed for shipment or shipped as a paste.One benefit of the process was that it was not necessary to dry the paste of white lead, removing its water. All that needed was to mill the paste with linseed oil, and the white lead would take up the oil and reject the residual water, to give white lead in oil.
White lead has been the principal white of classical European oil painting. There have been claims that it is partly responsible for darkening of old paintings over time, reacting with trace amounts of hydrogen sulfide in the air to produce black lead sulfide. Other authorities dispute this; the most traditional view is that impermanent pigments and dirty varnish (which is often cleanable) are more likely responsible for darkening.
Paintings and the role of varnish, which might protect the white lead yet itself darken, aside—according to Michelle Facini, a paper conservator at the National Gallery of Art, lead carbonate to lead sulfide is indeed what happens to some lead chalks/paints in drawings and watercolors and other works done on paper and unvarnished. Varnish is meant to be removable from an oil painting, to strip off when it dirties or cracks; but on paper it soaks through and becomes inseparable from the paper fibers, ruinous as it ages. This is why works on paper are never, or should never, be varnished.
In any event, white lead has been mostly supplanted in artistic use by titanium white, which is structurally weaker than white lead. Critics argue that many of these substitutes are much less permanent. White lead is less used by today's painters, not because of its toxicity directly; but simply because its toxicity in other contexts has led to trade restrictions that make lead white difficult for artists to obtain in sufficient quantities. Winsor & Newton, the English paint company, was recently restricted from selling its flake white in tubes and now must sell exclusively in 150mL tins.
In the eighteenth century, white lead paints were routinely used to repaint the hulls and floors of Royal Navy vessels, to waterpoof the timbers and limit infestation by teredo navalis worms
Other synonyms (as an art pigment)
Venetian Ceruse, flake white, silver white, slate white, Berlin white, Cremnitz / Kremnitz white, Crems / Krems white, Nottingham white, Vienna white
Pastiglia [pasˈtiʎʎa], an Italian term meaning "pastework", is low relief decoration, normally modelled in gesso or white lead, applied to build up a surface that may then be gilded or painted, or left plain. The technique was used in a variety of ways in Italy during the Renaissance. The term is mostly found in English applied to gilded work on picture frames or small pieces of furniture such as wooden caskets and cassoni, and also on areas of panel paintings, but there is some divergence as to the meaning of the term between these specialisms.
On frames and furniture the technique is in origin a cheaper imitation of woodcarving, metalwork or ivory carving techniques. Within paintings, the technique gives areas with a three-dimensional effect, usually those representing inanimate objects, such as foliage decoration on architectural surrounds, halos and details of dress, rather than parts of figures. In white lead pastiglia on caskets, the subject matter is usually classical, with a special emphasis on stories from Ancient Roman history.
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White Lead Pastiglia
In reference to work on picture frames and paintings moulded and gilded gesso is still commonly described as pastiglia, but in recent decades writers on furniture and the decorative arts tend to distinguish between this and "true" pastiglia, or white lead pastiglia which is defined as being made from white lead powder, made by combining powdered lead and vinegar in an anaerobic environment, bound with egg white. White lead bound with oil or egg yolk was also the most common pigment for white paint. White lead pastiglia is very delicate and used for small areas only, but can produce very fine detail. It was mainly used on small caskets and boxes. Sections were typically pre-moulded, doubtless from metal matrices to judge from the crisp detail, and glued on when hard. This was usually left unpainted, when it looked like carved ivory, which had been widely used to decorate boxes in Italy, by the Embriachi and others, but was by now less used, partly because it was too rare and expensive. The wood from which the main box was made was normally alder. It seems the term pastiglia for this only dates to the 17th century, after the technique had largely fallen from use. A scented variant called pasta di muschio ("musk paste") mixed musk perfume with the white lead, and was thought to be "aphrodisiacal", and so used for caskets given at a marriage, and also other objects such as inkwells and frames for hand mirrors.
White lead pastiglia was a north Italian speciality, produced between about 1450 and 1550. Six workshops were identified by Patrick M. De Winter, although their location remains uncertain; the Workshop of the Love and Moral Themes, whose products seem the most numerous, was possibly at Ferrara, where the painter Cosimo Tura began his career gilding caskets. Venice is also thought to have produced them. Other workshops identified by De Winter include the "Workshop of the main Berlin casket" and "Workshop of the Cleveland Casket".
The subjects were typically classical, drawn from both mythology and Ancient Roman history (especially the early period covered by Livy), but biblical ones are also found. Compositions can often be shown to be borrowed from another medium, such as prints or bronze plaquettes, and sections from the same mould can be found repeated, and used on more than one piece. The Victoria and Albert Museum has an armorial casket which is the only example that can be fairly closely dated, using the career of its owner, Cardinal Bernardo Clesio, as it must date to between his elevation as cardinal in 1530 and his resignation as Prince-bishop of Trent in 1538. De Winter catalogued 115 white lead pastiglia caskets, only 10 of which were over 20 cm high or deep. Another of this relatively large type was sold at auction in 2010. Despite usually having locks, their thin alderwood frame meant that the caskets were probably too fragile to be used for really valuable items like jewellery, and they are thought to have been used for a variety of small objects including cosmetics and collections of seals, coins and the like.
In 2002, the Lowe Art Museum in Coral Gables, Miami held an exhibition of Pastiglia Boxes: Hidden Treasures of the Italian Renaissance from the collection of the Galleria Nazionale d'arte antica in Rome, and an 80 page exhibition catalogue was published in English and Italian.
Gesso pastiglia is mostly found in Italy in the 14th to 16th centuries, where pastiglia on larger pieces of furniture such as cassoni, and on picture frames, was more likely to be gilded gesso than true white lead pastiglia. Both panel paintings and gilded frames had a thin flat layer of gesso as part of their preparation, to which the pastiglia decoration was added. On furniture and frames the gesso seems sometimes to have been carved from a thicker flat surface in a subtractive technique, and sometimes built up in an additive one, for smaller and larger areas respectively. Another additive technique was to simple pipe the gesso from a bag through a nozzle, like icing a cake, to give long round lines, often used as the tendrills in foliage designs. It was then always gilded or painted, usually the former. The technique was very widely used in painted panels while gold-ground paintings remained the norm for altarpieces, along with a range of other techniques for decorating plain gilded surfaces such as stamping, engraving or scratching lines, and stippling, punching or pricking dots. In Gothic architectural frames for polyptychs, pastiglia is very commonly used to decorate small flat areas such as spandrels and behind scalloped edges. The technique is described at the end of the technical handbook by Cennino Cennini, whose own paintings made use of it, although he does not use the term himself.
Madonna of the Quail by Pisanello
With the decline of the gold-ground style it became rarer within paintings, as opposed to frames, but was sometimes used for highlights, or a particular purpose. A famous portrait by Sandro Botticelli, who trained as a goldsmith, Portrait of a Man with a Medal of Cosimo the Elder (Uffizi, c. 1474), has the medal the subject is holding executed in gilded pastiglia, which apparently is an impression moulded from the original matrix for the metal medals, some of which survive.
Pisanello frequently used the technique; his The Vision of Saint Eustace (National Gallery, probably about 1540) shows a very fancily dressed courtier on a horse, and has pastiglia highlights on medallions on the horse harness, and the gold mounts on his hunting horn and his spurs, all gilded and representing pieces of goldsmith work. Such highlights are seen on other paintings by Pisanello, who was the leading medalist of his day, and familiar with modelling and casting techniques. Similar pastiglia medallions on horse-harness are found in the fresco Saint George and the Princess (Verona), and the Apparition of the Virgin to Saints Anthony Abbot and George (National Gallery). In his gold-ground Madonna of the Quail (Verona, attributed), the pastiglia is on the halos and borders of the Virgin's dress at neck and cuff, her crown, and in foliage decoration to the gold "sky", all typical locations in earlier religious paintings.
A generation after Pisanello, the conservative Carlo Crivelli continued to use pastiglia highlights in his panels, and it is used in Vincenzo Foppa's Adoration of the Kings (National Gallery) at the end of the century, in the crowns and gifts of the Three Kings.
The technique is rarer in fresco, but there are extensive areas of patterns in the cycle of the life of Queen Theodelinda in Monza Cathedral by the Zavattari family around 1440, no doubt using normal fresco plaster It was perhaps more common in decorating secular palaces than churches, but the vast majority of Gothic palace decorations are now lost. In England, it was used in the Painted Chamber of Westminster Palace as well as the much-damaged Westminster Retable painted panel, and in Early Netherlandish painting used in works such as the Seilern Triptych attributed to Robert Campin, where the gold skies have elaborate patterns of foliage, with a different design on each panel.
By about 1500, and with the advent of painting on more flexible canvas, which would not be a suitable support for pastiglia, use in painting disappears, but it continued on picture frames, where Renaissance gesso pastiglia generally consisted of vegetal motifs. During the 16th century cassoni and some frames became more massive, and woodcarving replaced pastiglia.
Cassoni and Book binding
Gesso pastiglia was very widely used on cassoni from the inception of the form in the 14th century. Early decoration tended to be repeated motifs derived from textile designs. Early cassoni were mostly either entirely painted or entirely decorated in gilded pastiglia, but by the 15th century painted panels were inset in elaborate pastiglia surrounds of mouldings - many of the paintings have now been detached and hang in museums. The subjects used for decorating cassoni in either medium had considerable overlap with those on white lead pastiglia caskets, with a heavy bias towards mythology. The paintings were typically by specialized workshops, of less quality than the leading local masters, but in the 15th century, many important painters sometimes produced them. Vasari complained that by his day artists looked down on this work, and by then more massive and elaborately carved walnut cassoni were in fashion.
The Victoria and Albert Museum has a Florentine example of a class of "coffrets" intermediate between caskets and cassoni, which is known by the motto Onesta e bella on its top, and would have been an engagement present from the future husband to his bride, formally presented to her by a representative from his family at her house, filled with small presents from the bridegroom's family. Smaller white lead pastiglia caskets were probably also used on such occasions. Made in about 1400, it is only 23 cm high and 61.5 cm wide and decorated with gilded pastiglia scenes made from gesso dura of courtly hunting and jousting on a painted blue field; these were apparently hand-modelled, not cast.
Plaquettes in bookbinding
Although the term "pastiglia" is not typically used to describe them, it is appropriate to mention "plaquette" bookbindings here. These are luxury leather bindings which incorporate, normally at the centre of the front cover, small inset plaquettes or roundels with designs in relief, which may be painted in colour. They appear towards the end of the 15th century, probably in Florence or Padua, and were at first used for special presentation volumes. Initially the designs were taken from antique carved gems. It was the famous, and rich, French bibliophile Jean Grolier who was apparently the first to use them systematically for his own books, while he was based in Milan as Treasurer for the French occupation; probably he began to commission them in 1510. He was also the first to use original designs, several of which showed scenes from Livy; altogether 25 Italian plaquette bindings for Grolier survive.
Some just use stamped leather, but for others the material used is variously described as "a sort of gesso mixed with varnish", or just "gesso",but these plaquettes can have extremely fine detail. What may have been Grolier's first such binding has a plaquette with 11 human figures and an architectural setting in a scene about two inches (50 mm) wide, showing Marcus Curtius leaping into the hole, the same subject as on the British Museum casket illustrated at the start of the article.
Pastiglia 12th-14th Century
The Czech School of Restoration has long devoted itself to the techniques of wall and panel painting. M. Hamsík and J. Tomek published an extensive study in 1983 on the technical parallels of the two branches of painting 1. M. Hamsík drew attention to further European centres where plastic decoration was used in painting and thus linked up with the long-term research of M. Frinta 2. The oldest examples of plastic elements in Czech wall painting are considered to be the haloes of the Pantocrator and angels in the Chapel of the Virgin Mary in the Monastery Church of St George in Prague Castle, from the 1st quarter of the 13th century 2a.
In his paper on European wall painting around the year 1200 O. Demus expressed the idea that this type of art became dead at the moment when walls were replaced by glazed windows in cathedrals 3. In this connection he drew attention to the wall paintings in St. Jacques des Guéretes, the author of which was inspired by the art of Limoges enamels and used it in the figure of Christ on the halo and especially in the painting of the drapery. The imitation of enamels in wall painting also preserved the nature of the partitioned enamel with its ability to change colours. In the chapter house of the Cathedral of Le Puy on the composition of the Crucifixion the haloes of the figures were gilded, as was the framing of the Cross and the hems of the cloaks of the figures. The colourfulness of the composition was enhanced by the blue background which was scattered with gilded raised circles. The researcher observed that local artists tried to enliven the wall paintings with the application of methods and effects from other techniques. The artists thus transposed one branch of art into another, counting on their complicated mutual relations. O. Demus did not suppose that the painter of the fresque in Le Puy was a goldsmith, he saw in him a painter of monumental paintings who must, however, have known and felt that »wall-painting had lost its specific monumental nature« and therefore used for its further development the means of other art techniques.
Similarly E. Lanc in recently published paintings from the castle of Petersberg near Friesach drew attention to the wealth of ornamentation carried out in stucco, in imitation of marbling and precious stones and in terra cotta ornaments on paintings of the 12th, 13th and 14th centuries 4. From the older Chapel of St Gebhard (around 1140) the figure has been well preserved of St Roman, Bishop and patron of the person ordering the decoration of the Chapel, the Bishop Roman of the time. (The painting has now been removed and deposited in the museum in Friesach.) St Roman was surrounded by pillared architecture with a semicircular enclosed arch, edged with diamonding. Over his white alba the Saint had a valuable pontifical robe. His dalmatica, patterned with diamond shapes, was edged with gold bands with imitations of precious stones. The casula was decorated with red hems adorned with pearls and precious jewels. It is obvious that the 12th century painter used motifs from the sphere of goldsmithing and artistic crafts. The researcher explains the origin of this decoration as a synthesis of Western and Byzantine influences. The younger Chapel of St Rupert was also decorated with stucco ornaments of Oriental or Western origin. For the first time of Austrian wall paintings there appeared on the figure of St Vigilius terra cotta applications, in relief and originally gilded. The actual painting was carried out by the tech-nique of lime secco with the addition of tempera. The intonaco was applied to plaster 1-2 cm thick and into this the underdrawing was painted. The haloes, the edges of the robes and the architecture of the throne were carried out in plastic relief in burnt clay and are among the oldest of this type in Austrian painting. The ornament of the other plastic ornaments was stucco. The paintings are from the years 1220-1225 and on the stylistic side represent a late phase of the Salzburg school of painting. The Chapel of St Rupert is quite exceptional in its entirety – the balanced nature and artistic effect of the chapel derived from the very combination of several art forms, the ornamental decoration and the delicate colouring, culminating in the gilded plastic reliefs. The raised treatment of Salomon's Throne shows its direct connection with the Biblical text of Ist Kings 10, verses 18-20, which describe the splendour of the tvory throne covered in gilded foil. It was most probably the technique of ivory reliefs which influenced the decoration of the moulds for terra cotta imitation Iconographically close are the paintings on the West empora of the cathedral in Gurk from the sixties of the 13th century on which rich plastic ornamentation was used on the haloes, brooches, the hems of the robes, but also on the framing areas with openings for intarsias of rosettes and quadrifoils. Similarly on the paintings in the Bishop's Chapel in Göss the openings in the haloes and in the framing of the medallions indicate that in them there were probably also terra cotta imitations or other plastic applications imitating precious stones. The paintings came into being around 1270 and, together with the paintings in Gurk, demonstrate the penetration of the so-called »Zackenstil« into monumental paintings 5. The terra cotta haloes and plastic raised decorations have been preserved best in the Gottweigerhofkapelle in Stein from the 1st decade of the 14th century 6. Undoubtedly the terra cotta plastic decorations here, too, were gilded and it is therefore an interesting question where this technique was taken from. In the three most famous Medieval tracts on painting and other techniques Heraclius wrote most widely about terra cotta, but more in the sense of practical and decora-tive ceramics 7. The idea of using decorations of fired clay could have been taken over from the monastery workshops, where they produced paving tiles, watt tiles and building elements – vaulting ribs, bolts, consoles, portal and window jambs. Here there clearly came into being the carved moulds for the shapes of the decorations used in the wall paintings. A characteristic fact is that in Austrian painting this technique, implemented in rich episcopal or cathedral areas, survived for almost one hundred years.
English monumental painting of the 2nd half of the 13th century also used raised decorations in the most important places, carried out by the techniques of enamels or goldsmiths' work. An example are the now famous monumental paintings of Westminster Palace in the form of precise copies or, in the case of paintings taken from the Chapel of St Stephen's, in partly preserved form; these paintings are today in the British Museum. Material for comparison are, for instance, historical objects from Westminster Abbey, especially the famous panel retable, the dating of which varies – it is either placed at the beginning of the 2nd half of the 13th century or at its end 8. P. J. Biński attempted, on the basis of copies from the so-called Painted Chamber in Westminster Palace, to reconstruct the original technique and method of decoration. He stated all the historical sources connected with the paintings and all accessible reports from the time of the discovery of the Medieval decoration. In connection with the reference to the combination of monumental paintings with the methods of other artistic professions especially the already mentioned enamels, goldsmiths' work and other works of artistic crafts – there are the important compositions of the Coronation of St Edward and the figures of the Virtues. The arcades bordering the individual figures and the baldaquin architecture of the Coronation scene show clearly, in spite of their indirect knowledge thanks to copies, that on monumental paintings there worked, apart from the painters, other artists who carried out the little enamelled plates with the motifs of heraldic black eagles and a trio of gold lions, framed in a motif of raised tendrils executed in gold and motifs re-calling pastiglia, clearly used on the royal crown, mitres, croziers and the reliquary case held by one of the Bishops. On the earlier Old Testament scenes plastic relief decorated the clothing and shields of the warriors. P.Biński stated, with reference to sources, that also the Royal bed was decorated in relief and he described the technique used according to a chapter from the tract of Theophilus Presbyter »De diversis artibus«, where the technique of intarsia is described 9. An English researcher compared the relatively true copy of the wall paintings with the probably contemporary panel retable from Westminster Abbey from the 2nd half of the 13th century which was executing using the tempera technique and the frame of which shows the same stamps for pastiglia as were used on the Westminster wall paintings. The technique of raised stamped ornamentation was also used on the tombstone of Edmund Crouchback and at an earlier period on the paintings from St Stephen's Chapel in Westminster. Restorers' investigations of these paintings showed the use of tempera technique and dry oils, the final colouring was carried out using the secco technique. Proof that the painters really did use oil as a binding agent is provided by accounts from theyear 1265, which mention eggs as well as oil; there are similar references in accounts from 1270 and in the nineties of the 13th century a combination of the technique of oil and glue is mentioned.
Detail of the varied applique on the de Bois Tomb at Ingham (Norfolk) – 14th century.
Apart from pastiglia the Westminster Retable is also decorated with little enamelled and glazed plates and above the wimberg with glass discs which recall a honeycomb. This means that in the Westminster workshop there were working alongside one another painters, goldsmiths, enamellers and probably also glass maker s who participated in the combined techniques of wall and panel painting. The Westminster works have long been compared with French painting and French crafts, not only because of the French inscriptions and the close kinship of style, but especially because of the artistic preliminary stage of combined techniques.
Petersberg Castle near Friesach (Kärnten, Austria). Plastic elements in wall paintings of the Chapel of St Virgil (on the left) and of the Chapel of St Rupert – »Solomon's Throne« (on the right).
The researcher drew attention to the châsse in St. Taurin in Evreux, completed in 1255, the reliquary from the Ste Chapelle from the same period and a further châsse from the Ste Chapelle, now known only from a drawing. P.Biński found a parallel to the glass applications in the retable from St Denis from the middle of the 13th century. Mentioned in connection with French art was the decoration of the Ste Chapelle, the interior of the Lower and Upper Chapel. On the painted decoration of the interiors in the Ste Chapelle use was also made of metal objects, glazing, gilded raised backgrounds, false enamels combined with the actual architectural decoration.
Plastic decoration was a progressive element in the technique of wall paintings and panel altars, the use of which we find in works of the 14th and 15th centuries, especially in East Anglia (Norwich, Ipswich, etc.). Typical and very well known is the newly reconstructed altar, probably originally intended for the Dominican Monastery in Thedford, today in ruins 10. The reconstruction was carried out by English researchers who managed to show convincingly that the altar panels now displayed in the Musée de Cluny in Paris, depicting Marian scenes, undoubtedly formed the lower part of the altar, the remaining part of which is now kept in the little parish church in Thornham Parva. The centre of this altar is the Crucifixion, the row of saints ends at either side with St Dominic and St Peter the Martyr, securely indicating the Dominican origin of this panel altar from the years 1320 – 1330. One of the reasons for the linking of the two retables is the very close link of the use of the same stamps for the relief treatment of the gold background to the paintings. The pastiglia combine a vegetable design and a form of chessboard arrangement of dark platelets with lilies in combination with a gold ornament. Apart from the already-mentioned goldsmith's techniques P. Biński also drew attention to the decoration of book bindings where the leather-covered boards were imprinted with ornaments using stamps with various motifs (lilies, leaves, etc.). Their similarity to the designs on the wall paintings in St Stephen's Chapel in Westminster shows another possible origin or inspiration for the painters of wall paintings.
As in Austria, so also in English Romanesque monumental painting there were found raised gilded stars on the vaulting in the Chapel of the Guardian Angels in Winchester and these can be seen as a preliminary stage to the later decoration in Westminster 11. In this connection P. Biński mentioned the decoration of the vaulting in the lower Church of St Francis in Assisi, where the vaulting was inlaid with little mirrors imitating the sparkling stars.
A further area where the cooperation of the painters of wall paintings and panel altars with the goldsmith's techniques used on the backgrounds of painters' works was very close is shown by Cologne on the Rhine 12. The paintings on the choir stalls of Cologne Cathedral (6 stone walls 5.6 m wide, 2.8 m high and 0.43 m thick) are dated thanks to the portrayal of the last Bishop Walram von Jülich in the years 1332 – 1349. On the outer walls the background of the saints portrayed is carried out with gilded pastiglias in the shape of diamonds and spiralling rosettes. The technological investigation of the paintings showed the following composition of layers: the stone, which here functioned as the support, was coated with a layer containing yellow ochre. There followed a layer of calcium carbonate (chalk) to which was again applied a coat of ochre as a primer. After the under-drawing in wood charcoal there followed the layered application of the pigments usual in panel painting 13. Ivan Bentchev emphasised that the ground for the wall painting here was not plaster, but a chalk ground and he substantiated the ascertained procedure with quotations from the tracts of Heraclius and Theophilus 14.
The patterns of the pastiglia on the outer walls of the stalls have close analogies in the later panel altar of St Clare, where the technique of the painting is also similar. As far as technical details are concerned I would refer you to the detailed study by Bentchev already mentioned here. An interesting detail is the priming coat of ochre, minium and glue binding agent, also containing resin and oil components, further the »stamping« of the pastiglia in the ochre-minium material. In the rotating rosettes there were also hollows for the setting of pearls, which again has an analogy in the panel altar of St Clare. Also decorated similarly to these two works was the pillar in the Choir and probably also the side chapels. Apart from a number of works in the Cathedral, this workshop was also active in other churches in Cologne (e.g. St Cecilia, St Severin, St Cunibert and the Minorite Church). Outside Cologne the activity of the workshop can be localised to Steinfeld, where the Crucifixion and the Last Judgement were ordered by the brother of the Bishop of Cologne, Wilhelm von Jülich (1328 – 1361). Around the years 1360 – 1370 the wall paintings in the Hanseatic Hall of the Cologne Townhall were carried out in tempera technique, also on a chalk ground. It is clear, then, that in Cologne the painters' workshop used the tempera technique for monumental painting for more than two generations, but its activity was clearly limited to Cologne and Steinfeld.
Charles' period brought to a peak the idea of the combination of painting and artistic crafts to the extent that believers did not have to admire only beautiful work (raised gilded imitations), but also precious material in the shape of real semi-precious stones. The combination of semi-precious stones with gilded pastiglia in the St Vitus' Cathedral and in Karlštejn Castle shows the continuity of the links between monumental painting and the techniques of other fields which, as we have tried to prove, was characteristic of a number of European artistic centres for more than a hundred years.
Well, my carbon prints have a raised relief, but no precious or semi-precious stones (or metals).
At least with LF landscape, a bad day of photography can still be a good day of exercise.