Green Glaze Research Articles

Technical Examination of a Fifteenth-Century German Illuminated Manuscript on Paper: A Case Study in the Identification of Materials

SummaryTechnical and analytical studies were carried out on a fifteenth-century German illuminated manuscript, Barlaam und Josephat, in the collections of the J. Paul Getty Museum. Deterioration of the paper support has occurred as a result of interaction with the copper green pigments used extensively for illumination. The green pigment was determined by X-ray diffraction to be a variety of basic verdigris and the binding medium, analysed by gas chromatography-mass spectrometry (GC-MS), was determined to be egg. A dark green glaze was shown to have a glue binder, and is an example of a copper-proteinate complex. An organic red, also in a glue binder, was characterized by thin-layer chromatography and UV/vis spectroscopy as rhubarb, mordanted with alum. Rhubarb has not been previously identified as an organic red colorant in illuminated manuscripts. Vermilion, azurite, lead white and an unidentified organic yellow were also employed in the decoration. Discussion of the artistic milieu in which the manuscript was produced includes comparisons with well-known manuscripts of the fourteenth and fifteenth centuries such as the Strasburg Manuscript and the Göttingen Model Book. The possible options for conservation treatment of the embrittled paper support are discussed.

Parasitism of Bemisia argentifolii on Collard with Reduced or Normal Leaf Wax

Collard, Brassica oleracea var. acephala L., cultivars with reduced leaf wax (i.e., glossy phenotypes) possess ovipositional antixenotic resistance to the silverleaf whitefly, Bemisia argentifolii Bellows & Perring (Homoptera: Aleyrodidae). We investigated parasitism by 2 parasitoids of B. argentifolii reared on 2 phenotypes of the collard cultivar 'Green Glaze', differing in amount of leaf wax. When Eretmocerus sp. (Hymenoptera: Aphelinidae) parasitoids were given a choice between parasitizing whitefly nymphs on glossy and normal-wax collard, there were no significant differences in the number of parasitized nymphs on the 2 plant phenotypes. However, 4.5 times more Encarsia pergandiella Howard (Hymenoptera: Aphelinidae) emerged from whiteflies on glossy than on normal-wax plants. In a no-choice test, the number of Eretmocerus sp. emerging on glossy and normal-wax plants did not differ significantly. In a similar no-choice test, more than twice as many E. pergandiella emerged from whiteflies on glossy collard than on normal-wax collard. Time to 50% emergence for whiteflies and both species of parasitoids did not differ on the 2 collard types in any of the no-choice tests. We conclude that management of B. argentifolii populations can be improved on collard, and probably other B. oleracea vegetables, through the use of reduced leaf wax cultivars that have antixenotic resistance to B. argentifolii and have no detrimental effects, possibly even beneficial effects, on important whitefly natural enemies.

Effects of planting pattern of collards on resistance to whiteflies (Homoptera: Aleyrodidae) and on parasitoid abundance.

Fourteen collard entries, Brassica oleraceae L., Acephala group, were evaluated for resistance to natural populations of Bemisia argentifolii Bellows & Perring in replicated field plots in Charleston, SC. Glossy-leaf phenotypes ('SC Glaze', 'SC Landrace,' 'Green Glaze') were the most resistant collard entries and had fewer whiteflies than the nonglossy, open-pollinated cultivars. Also, two F1 hybrid cultivars with normal, nonglossy leaves ('Blue Max' and 'Top Bunch') were resistant. In laboratory experiments, there were no differences in the intrinsic rate of growth (rs) of B. argentifolii populations on either glossy or nonglossy collard phenotypes. Over a 2-yr period, there were no differences in the abundance of whiteflies on the glossy phenotype of Green Glaze when it was planted in solid 20-plant plots or when it was alternated (every other plant) with the nonglossy phenotype of Green Glaze. In a similarly designed experiment, there was no difference in the resistance of Blue Max in either solid or mixed planting scheme compared with the susceptible 'Morris Heading'. Higher numbers of whiteflies and parasitoids (primarily Eretmocerus spp.) were collected on yellow sticky cards in the solid plantings of the nonglossy phenotype of Green Glaze than were collected in the solid plantings of the glossy Green Glaze phenotype. Counts on sticky cards in the mixed plots were intermediate. These data show that planting pattern of collard entries is relatively unimportant in the deployment of these sources of host plant resistance. The data also suggest that nonpreference is the primary mode of resistance to whiteflies for certain collard entries.

Relationship between Color of Chromium Oxide in Lime Glaze and Chemical Composition of Glaze.

Relationship between color of chromium green glaze fired at 1280°C under oxidation atmosphere and its chemical composition was successfully analyzed by a newly developed method measuring absorption and scattering coefficients. Sixteen glazes were prepared by adding 0.25mass% Cr2O3 into the base glazes with Segar formulars of 0.3KNaO, 0.7CaO, xAl2O3, ySiO2 (x=0.35, 0.40, 0.45, 0.50; y=3.5, 4.0, 4.5, 5.0). Complicated changes in the apparent color of the glaze were observed because of the occurrence of several elemental changes in the absorption and scattering coefficients. The decrease in the scattering coefficient with increasing Al2O3 amount could be related to the amount of a Wollastonite crystalline phase, which had a significant influence on the apparent color of the glaze. Relationship between absorption coefficient and glaze composition could be clearly detected, which indicated a change in chemical state of Cr.

THE WINGS OF HANS MULTSCHER’S WURZACHER ALTAR: THE USE OF STENCILS FOR THE PAINTING OF FOLIAGE

"THE WINGS OF HANS MULTSCHER’S WURZACHER ALTAR: THE USE OF STENCILS FOR THE PAINTING OF FOLIAGE." Studies in Conservation, 43(sup2), p. 5

Re-Evaluating Late Nineteenth Century Creative Innovations in the Silicate Industry: The Zsolnay Ceramics Works of Pécs, Hungary

The Zsolnay ceramics factory was founded in the old, culturally rich south Hungarian city of Pecs in 1853, by the merchant, Vilmos Zsolnay (1828-1900) at the start of the industrial development of the area. From a small cottage industry, the extraordinarily gifted and driven Vilmos, his children and descendents, built up the firm into a huge complex which at the time of his death was at its peak, employing over 1000 workers, who produced a great variety of the most unusual and creative utilitarian and decorative ceramics products which earned Zsolnay worldwide recognition even today. Initially Vilmos continued his activities as a merchant but became more and more involved in the ceramic operation. He and his two teenage daughters were self-taught in ceramics. They at first designed and made the simple but beguiling rustic crockery, based on traditional Hungarian models. Their interest in local folk arts and crafts gave rise to the sisters' splendid collection of ethnic textiles and embroideries which served also as inspirations for their earliest designs. Vilmos moved the premises, bought additional lots, continually enlarged the plant and bought up clay deposits, coal mines, and other industrial properties to enhance his operations. He took chemistry lessons, and concentrated on refining and improving the quality and appearance of his products. By 1873 he had developed his trademark porcelain-faience fired ware, a warm yellowish white body, with colored glaze decorations, amassed an art history and ceramic reference library and ceramics sample collection, and sent his daughters Terez and Julia to study and copy traditional Iranian, Turkish, Japanese and Chinese designs from the collections and books in the academic libraries of Vienna. The 1873 Vienna World's Fair brought Zsolnay's first success: the bronze medal, diploma, and Franz Joseph Order, for the displayed eclectic and Renaissance style pots, vases, pitchers, pharmacy white ware, and simple but charming rustic Hungarian wares. Orders followed from England, France, Russia, America, and from the Austro-Hungarian Empire's most promintent personages. Decors such as the Godollo, the Rothschild Orchid, the Pheasaut, were originated by the sisters and by newly hired artists such as Armin Klein, Kelemen Kaldeway. From 1874 Vilmos further expanded the range and improved the quality of his products, developed the Old Ivory technique, hired artists whom he trained, not to slavishly copy historic models, but to develop and express their own personal style. He established the factory's museum to inspire the workers, and improved their living, working, and social conditions. The 1878 Paris World's Fair brought Zsolnay the highest recognition, the Grand Prix and Legion d'Honneur. From this period date such innovations as the denser, high fire wares, decorated with cobalt, black, red and green glazes in the Chinese manner, the celadon and turquoise glaze, the tiger or coagulated glaze, the gold brocade and metal techniques, the grain de riz, and glass techniques. The Viennese Ernst Wahliss and Jules Houry in Paris became exclusive foreign representatives, and 80% of production was exported.

Excavated Iznik Kilns and Characterization Studies of the Kiln Furniture

The term Iznik ceramics refers to the pottery and tiles produced in the town of Iznik, Turkey during the reign of Ottoman Empire, in the period between 14th through 17th centuries. Those ceramics have been classified into different groups, such as, Miletus, Abraham of Kutahya, Golden Horn and Damascus wares based on their style but not indicating a provenance. Although, on the basis of its production technology, Iznik ceramics represents the general Islamic ceramic tradition, the Iznik potters succeeded in producing ceramics of a very high quality characterized by a wide range of vivid colors under a brilliant lead-soda glaze during 16th century. It was generally thought that such quality wares could not be produced by Ottoman craftsmen and they were attributed to Iran, Rhodes, Damascus, Kutahya and Golden Horn of Istanbul. Red bodied pottery produced in Iznik during the second half of the 14th century and the beginning of the 15th century was named as Miletus ware because of the similarities with the wares excavated around Miletus in the 1930s. However, the excavations of the kilns in Iznik started in 1963, by Prof. Dr. Oktay Aslanapa proved that these findings had actually been produced in Iznik. The production of Miletus wares continued well into the 16th century (circa 1520) together with the newly developed fritwares of the 15th century. This new fritware with its lead rich body was quite different from the earlier alkaline frit of the Iranian and Memluk wares. Thus it is assumed to have evolved as a new technique in iznik. A total of three kilns have been recovered in Iznik since the excavation started. Two of the recovered kilns are cylindrical in shape having 2 m diameter and being 2 m deep were found at the same location side by side. Kilns were separated from each other by a piece of a marble column. Both kilns have a circular entrance on the top. Third kiln was recovered rather away from the other two, having parallelepiped shape with a cross section about 180x150cm measuring 2.5 m in deep Top of the kiln was found to have caved in and it seems that there is an entrance from the side wall. This kiln has a niche on the interior wall to place the shelves. Interior all of the kilns recovered were covered with large refractory red bricks. During the cleaning process of the kilns, lots of sherds having red and white body were recovered. Those sherds including the Miletus, Abraham of Kutahya, Damascus, Golden Horn wares and sherds decorated by sgraffito and slip techniques with colored glaze (cuerda seca). Fired red body undecorated (biscuit) and unglazed sherds were also found. In addition to the sherds, many kiln furniture including supports, tripods were recovered during the excavation. Sherds with colored glaze were also recovered at Kalehisar excavation site in Corum, Turkey, belonging to 13th century Seljuk settlement. Therefore it is assumed that the Seljuk ceramic tradition influenced the Ottomans. Even though there is no documentary evidence, the quality of the Palaelogian earthenware excavated in the area suggest that iznik was a pottery center since Byzantine era. The body of the finds was red and the glaze was shiny, very similar to the early Iznik wares of the 14th century decorated with slip technique. The red body and the green lead glaze of the tiles of the Orhan Gazi Imaret (1334/35) suggest a continuation of the Byzantine tradition.

TECHNOLOGY AND COLOUR DEVELOPMENT OF HISPANO‐MORESQUE LEAD‐GLAZED POTTERY

Lead‐glazed pottery from the medieval workshop of Les Olleries Majors (Paterna, Spain) has been studied by Mössbauer spectroscopy, X‐ray diffraction, X‐ray fluorescence and optical spectroscopy. Yellow, brown and honey‐coloured glazes occur on pots glazed on only one surface. They have virtually identical compositions and transmittance spectra, their apparent differences in colour are due to the colours of the underlying pastes. Yellow glazes occur on cream‐coloured calcareous bodies, honey‐coloured glazes occur on less calcareous bodies with some development of hematite, while brown glazes occur on red siliceous cooking‐pots. Green glazes are found on pots glazed on both surfaces; the glazes trapped CO2 evolved by decomposing carbonates, resulting in an internal reducing environment. This caused the reduction of iron to the ferrous state which coloured the glaze green by diffusion.

La céramique chinoise de la donation Maspero au musée national des Arts asiatiques - Guimet

The dating of Chinese ceramics from donation Maspero ranges from the Tang Dynasty to the end of the Yuan Dynasty. Most are shards but some are rather large fragments which can be reunited to form complete pieces. The majority of the ceramics are dated XIth-XIIth and end of XIIIth-XIVth century. This collection is particularly interesting as it testifies to the presence of these particular types of Chinese ceramics in Vietnam. The total amount is about 800 pieces ; around 20% are ceramics from the Guangdong kilns such as those of Xicun or Chaozhou dating from the Xth to XIIth century. They are stoneware with pale olive-green glazes and with incised and combed designs ; about 8% are greenglazed wares with incised or moulded decoration, with the well-known sickle-leaf scroll from Yaozhou kilns in Shaanxi but also from Guangdong or Guangxi kilns ; about 12% are qingbai ceramics mostly dating from XI-XIIth century but some with moulded decor of a later period production are also present ; there are also few sherds of copper green glazed bowls which could come from Guangxi. There are some Fujian stonewares with olive green glaze and incised decoration from the end of XIth or beginning of XIIth century, some black glazed bowls of Jian kilns and a few pieces from Dehua with moulded designs. But the most numerous amount of ceramics are celadons from Longquan kilns — about 1/3 of the total — with a very wide range of different patterns for the Yuan period. The influence of Chinese ceramics on Vietnamese ceramics is here so obvious that it has been difficult to give a precise attribution for some of them. Moreover some ceramics from the Yaozhou kilns and other Chinese kilns, such as those of Guangdong and Guangxi, have brown colored bases which is considered to be characteristic of the Vietnamese style ; this anomaly is due either to natural reactions to firing conditions or to a slip. Their presence in Vietnam could have been an incentive to later on chocolate-brown bases. Several questions are raised even if the exact location of the discovery of the donation's ceramics is hypothetical. The small number of Fujian ceramics is surprising as it is well known how numerous the exports of these were, from the end of Xith to the XIIth century. Similarly, why are there no Blue-and-White ceramics when there is so much of XIVth century celadons to be found ?

Recognition of Brassica oleracea L. Resistance against the Silverleaf Whitefly

Resistance of a Brassica oleracea germplasm collection (broccoli, Italica Group; cauliflower, Botrytis Group; and collard and kale, Acephala Group) to silverleaf whitefly (SLW; Bemisia argentifolii Bellows and Perring) infestation was evaluated using several measures of insect infestation (including adult vs. nymph counts) taken at plant growth stages ranging from seedling to mature plant. An initial study was conducted in an outdoor screen cage artificially infested with the SLW adults; subsequent field trials relied on natural infestations. The glossy-leaved lines (`Broc3' broccoli, `Green Glaze' collard, and `SC Glaze' collard) had low SLW infestations in cage and field tests. SLW adult counts were less variable than similar comparisons using nymphal counts, although adult and nymph counts were positively and significantly correlated at late plant stages. Based on this study, comparing relative SLW adult populations would be a preferred criterion for identifying B. oleracea resistance to this insect.

Colored nonfritted glazes from available raw materials for facade ceramics

Results of synthesis of green glazes based on datolite concentrate, glass fiber scrap, and galvanic slime with additives are presented. The physicochemical properties of coatings and special features of their formation, phase composition, and structure are described.

XPS, ICP and DPASV analysis of medieval pottery ? Statistical multivariate treatment of data

Medieval ceramic sherds have been studied by inductively coupled plasma (ICP) emission spectroscopy and X-ray photoelectron spectroscopy (XPS) in order to acquire knowledge about technological achievements in pottery production in Apulia during the Middle Ages. The XPS results allow to characterize the surface glazes, which are transparent owing to the presence of PbO or opaque-white in case of Sn addition. The study of coloured glossy surfaces, after an optimized chemical etching, has also shed light on the pigment nature of the painted decorations, whose red colour is to be attributed to the presence of Pb3O4 and not of Fe oxides. Quantitative determinations were performed by ICP measurements on samples of differently coloured glazes, clayey slips and ceramic bulks. Pb and Cu, present in one green glaze, were also determined by differential pulsed anodic stripping voltammetry (DPASV). The analytical results were treated by different statistical techniques of multivariate analysis.

Response of Caterpillar Pests and the Parasite Diadegma insulare to Collard Cultivars and a Pyrethrin Insecticide

There were no differences in mortality, plant preference, or plant damage when diamondback moth (DBM) (Plutella xylostella L.) larvae were tested in no-choice and free-choice tests using leaf disks of resistant (`Green Glaze') or susceptible (`Vates', standard commercial cultivar) collards (Brassica oleracea Acephala group). No residuals of the pyrethrin insecticide Asana-XL (esfenvalerate) were detected 6 days after its application when DBM larvae were exposed to excised foliage for 72 hours. In a field test, more imported cabbage worm (ICW) (Pieris rapae L.) eggs were found on `Vates' treated with the insecticide than on nontreated Vates' or nontreated or treated `Green Glaze'. The fewest ICW, cabbage looper (CL) (Trichoplusia ni Hubner), and DBM larvae were found on the insecticide-treated cultivars. Fewer caterpillars were found on `Green Glaze' than Yates'. An additive effect of plant resistance and insecticide application lowered counts of DBM, ICW, and CL larvae. Percent parasitism of DBM by Diadegma insulare Cresson (Hymenoptera: Ichneumonidae) was lower on cultivars treated with the insecticide. Field plant damage ratings were higher for nontreated `Vates' and lowest for treated cultivars, but nontreated `Green Glaze' had a significantly lower feeding damage rating than nontreated `Vates'. Chemical name used: (S)-cyano (3-phenoxy phenyl) methyl-(S)-4 chloro-alpha (1-methylethyl) benzeneacetate [esfenvalerate (Asana-XL)].

A Compositional and Microstructural Study of Korean Celadon Glazes of the 11th to 15th Centuries

AbstractCeladons--stonewares with pale green or greenish-blue glazes--have a rich and varied history in ancient China that begins in the Eastern Han period (A.D. 20-220) and extends nearly 1500 years [1]. The initial development of celadon wares in Korea probably dates to the late 9th century [2,3]. The zenith of production was in the llth-12th centuries, during the Koryŏ dynasty (918-1392); celadons continued to be produced into the 15th century. In form and type, the earliest Korean celadons were clearly based on Chinese models, although by the middle of the Koryo period uniquely Korean forms and decorative techniques had been developed, notably the use of white and black inlays. During the Koryŏ period, celadons were probably produced exclusively for court circles and for use in Buddhist temples. Some 270 Koryŏ period celadon kilns have been found to date. The greatest concentration (about 240) occurs in Chllla province in the south; the major areas of production were around Kangjin and Puan.

Post-Medieval Pottery (16th/17th-18th century)

Five sherds were submitted for study: three from trench A, context 1; and two from trench E, context 1. Those from trench A include: 1 sherd of orange ware with internal mottled green glaze; 1 sherd of orange ware with intelai orange-brown glaze; and 1 sherd of Staffordshire combed ware. Of the Merds from trench E, 1 is of pale orange/buff ware with internal mottled green glaze; and the other is of orange ware with partial external light green glaze and internal green glaze above applied, raised decoration in the form of pellets and lines.

Note on the Green and Brown Glazes of Old Paintings

Note on the Green and Brown Glazes of Old Paintings

Dansk middelalderlertøj med antropomorf dekoration. Et bidrag til den blyglaserede kandes historie

Dansk middelalderlertøj med antropomorf dekoration. Et bidrag til den blyglaserede kandes historie

Glossy-leaf in collard (Brassica oleracea L. var. Acephala D.C.): An incomplete dominant

Glossy-leaf in the collard variety “Green Glaze” is incompletely dominant to waxy foliage normal in other varieties; the suggested gene symbol is Go. The phenotype is similar to that controlled by a recessive gene in Brussels sprout. Further loci may be involved in other glossy-leaved forms reported in B. oleracea and such genes would form a useful series of markers in a breeding programme.

ZINC‐VAPOR GLAZING OF CLAYS: I*

AbstractA study was made of the influence of the iron‐oxide and alkali contents and absorptions of clay bodies on their ability to take a zinc‐green vapor glaze. Although greens may be obtained on bodies with a wide range of compositions and with absorptions up to 8.4% under exacting conditions, the range of bodies which take a green glaze under less favorable circumstances is comparatively small. The probability of obtaining good greens was greatest with those bodies whose absorptions were below 2% and which contained 8 to 18% iron oxide and more than 6% alkalis. Firing to higher temperature and cooling rapidly improved the tendency to produce greens. Desirable tans, browns, brick reds, and grays were obtained by firing to low temperatures and cooling slowly.

Research Items

Mortuary Caves of Szechwan, China. Relics from the artificial caves of Szechwan Province in western China have been described by the collector, Mr. David C. Graham (Proc. U.S. Nat. Mus., Art. 16, vol. 80). Thousands of these artificial caves are to be found in the sides of the hills and cliffs from Hupeh Province on the east to the highlands of the Szechwan-Tibetan border and along the Yellow River in the province of Kansu. Varying from a few feet to 130 ft. in depth and about six feet high by six feet wide, they are carved from the solid stone, the sides plainly showing chisel marks. Some are so close to one another that holes have been knocked in the dividing walls. It is popularly believed that they are barbarian; but on both historical and archaeological grounds it is demonstrable that they do not antedate the Chinese and almost certainly belong to the Han dynasty at about the beginning of the Christian era. The best caves have elaborate carvings above and around the front openings and on the sides and pillars near the entrance. Certain conventional designs in these carvings are also found on Han monuments of various types. A large number of burnt clay figures have been collected from the caves. Glazed figures are rare, but a fragment of a bottle-neck and part of a pottery bell show a green glaze. The figures include the foot of an elephant, dogs, fowls, horses heads, human figures among these, servants, actors, a figure playing a flute, etc., in costumes which indicate that little change has taken place in dress down to the present day. The clay vessels show the use of the potters wheel. The commonest artefact is the earthenware coffin. Many carvings and artefacts reflect customs or represent implements in present use among the Chinese, but not among any primitive tribes.