TECHNICAL QUESTIONS ABOUT HISTORICAL GLASS

THE FOLLOWING PAGES DISCUSS THE TECHNICAL ASPECTS OF HISTORICAL GLASS.

(Click on title questions to see the discussion pages)

WHAT IS THE CHEMISTRY OF ROMAN GLASS ?

Roman Glass, Allaire Collection

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WHAT IS THE DIFFERENCE BETWEEN OPAL, DICHROIC AND OPALESCENT GLASS?

 

104E Art Nouveau glass vase 1890-1900

1925 Lalique Suzanne Art Deco Opalescent Glass

1925 Lalique Suzanne Art Deco Opalescent Glass

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WHAT IS THE IRIDESCENCE ON ANCIENT GLASS ?

24R Roman double balsamarium 4-5th C

32R Roman candlestick balsamarium 2-3rd Century 18.5 cm

 

WHAT IS THE IRIDESCENCE ON ANCIENT AND MODERN GLASS ?

 

Tiffany’s Favrile “Pansy” vase 1894

Hans van Rossum collection of glass

 

 

CLEANING ANCIENT AND ARCHAEOLOGICAL GLASS

 

Before

After

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WEATHERED ARCHAEOLOGICAL GLASS

22R before cleaning

22R after first cleaning

22R after second cleaning

BRITISH MUSEUM COLLECTION ONLINE

Picture of British Museum – Wikipedia

The British Museum has a new service most of their collections are now online. This service has been completely redeveloped, making it much easier to find what you want. It allows access to almost four and a half million objects in more than two million records. The search is more intuitive and now offers suggestions as you type.

High definition images can be enlarged and examined in detail which will enable you to view the incredible workmanship on the Royal Game of Ur, the intricate carving on this African hunting horn, the amazingly preserved deerskin map from North America, or this delightful drawing by Raphael of an old man’s head – just a few of the thousands of highlights to discover.

Enjoy exploring the collection – from some of the earliest objects created by humankind to works by contemporary artists. Or choose from the curated collections below, which reveal the fascinating stories that transcend time.

https://www.britishmuseum.org/collection (ACTIVE LINK)

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Additional active link to the glass collections at the British Museum on The Ancient Glass Blog of the Allaire Collection

THE BRITISH MUSEUM: POST ROMAN AND MEROVINGIAN GLASS 5TH – 7TH C

TWO BEAUTIFUL EXAMPLES OF ROMAN GLASS IN THE BRITISH MUSEUM

SNAKE-THREAD ROMAN GLASS VESSEL IN THE BRITISH MUSEUM

TIFFANY’S FAVRILE “PANSY” VASE

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The form of this Favrile “Pansy” vase was first made by glassmaker John Hollingsworth (American, born England, 1851–1923). Hollingsworth, and all of Tiffany’s talented glass makers, were encouraged to experiment at the furnace. The iridescent sheen of this “Pansy” vase was achieved by spraying tin chloride on hot glass and reheating it in a reducing (decreased oxygen) environment. Although the term “Favrile” is often used to describe Tiffany’s iridescent glass, “Favrile” was actually used to describe all glass produced by the factory. On November 13, 1894, Tiffany registered “Favrile” as a trademark with the US Patent office (no. 25,512). Taken from Corning Museum of Glass web site.

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WHAT IS THE IRIDESCENCE ON ANCIENT AND MODERN GLASS ? (Active Link)

THREE VENETIAN TYPE GLASSES

Three Venetian type glasses from the Henk-Martin Goldschmidt collection

Finding the site and date of origin of any glass object is a challenge. And even the most experienced person has sometimes doubts. Of course many characteristics can be used for an estimate as good as possible. However a set of objective, measurable criteria would be most helpful. In addition one has to admit that the overall knowledge, from the ancient periods as well as from the more recent times, is rapidly expanding. The conferences and papers of International Association for the History of Glass (AIHV) and The Istituto Veneto (ATTI) largely contribute but also the activities of The Corning Museum of Glass as well as from many others. Here three Venetian type glasses are described and the challenge for the inexperienced glass collector is obvious.

Description: three Venetian type glasses (LTR) :

(I)         a Venetian Winged glass, second half of the 17^th century or early 18^th century ,

(II)       a Salviati glass, Venice around 1870 and

(III)      a flute type glass made and signed by William Gudenrath, Corning 2018.

(I)

Wineglass with bleu wings, colorless glass with a hint of grey

Description: Bowl-shaped cup with on the bottom so-called nipt diamond waies with, a little highe, a thin, horizontal glass tread. The cup is made in the mezza-stampaura technique. One third of the bowl is covered with a second layer of glass, which is then blown in a star shaped dip mould, a form with twelve vertical ribs. Only the part that is double-walled, touches the inside of the form, resulting in twelve vertical ribs at the lower side of the bowl. Halfway these are pinched together in which way a diamond pattern is formed.  Hollow diagonal ribbed stem with four nobs on top of a small pipe or cigar formed segment. The stem has 16 ribs. At both sides a wing with an aquamarine colored base with decorations of colorless glass. Cup and stem are connected by means of a merese. Conical foot.

Material:        Cristallo and aquamarine colored glass

Date:                 Second half 16^th,  17^th century

Origin:             Venice

Provenance:  acquired from Laméris, Amsterdam, 2016

Dimensions: Height 13.3 cm, diameter cup 9.4 cm, diameter base 8.5 cm, weight 86 gram and capacity 149 ml, so lightness ratio (capacity in ml / weight in gram) 1.7 (not more, due to the nipt diamond waies application)

Condition: perfect except minute chip at the bottom rim, which can only be seen with the aid of a loupe

(II)

Wineglass with blue wings

Description: long bell-shaped cup with four rings at the bottom side. Conical hollow stem. At both sites a wing with green-blue glass and pinched decoration in colorless glass. Slightly conical, almost flat base with an elevation in the middle.

Material:        colorless glass and green-blue glass

Date:                 Second half 19th century, could well be1866 – 1867

Origin:             Venice, probably Salviati

Provenance: Collection Bomers-Marres (Number BM 43) bought from the late Henk C. van Vliet, Amsterdam, acquired from Laméris, Amsterdam, 2016

Dimensions: Height 20.9 cm, diameter cup: 7.8 cm, diameter base: 7.7  cm, weight 91 gram and capacity 168 ml, so lightness ratio (capacity in ml / weight in gram) 1.8

Condition: perfect

Parallels:       A glass with comparable wings and a differently shaped cup is depicted in a catalogue of Salvati in London. The Salviati catalogue states as follows for this specific glass: No 414, Description Champagne Glass, Clear 2.0 , Ordinary Colours 2.6 , Ruby Opal sc 3.6 , Filigree Ritorto Arrenburine 4.6 , Riticelle 5.0 . However the exact copy is not yet found in one of the Salviati catalogues.

(III)

Champagne glass with a trumpet-shape

Description: Trumpet-shaped bowl, leg (verre a jambe) or cigar shaped blown hollow stem, connected with bowl and stem by a merese. Slightly conical foot, connected with the stem again with a merese (a glass disc). “The glass illustrated here is made from three bubbles, or parisons, with two discs that separate bowl from stem and stem from foot. The stem is a hollow-blown column, swelling slightly toward the top and having an outer and an inner line of great elegance. The plain foot rises slightly in the center to give a concave curve taken up by the line of the lower part of the stem and by the superb sweep of the spreading bowl.” William Gudenrath made and signed this glass. He is a contemporary glassblower who is capable of making the same glasses as in renaissance Venice. His extraordinary achievements are well documented by numerous movie files on the Internet. On top of that he is an excellent scholar and teacher at The Studio of The Corning Museum of Glass in Corning, NY.

Material:        colorless glass

Date:                 2018

Origin:             Corning by William Gudenrath (incised signature)

Provenance: Gift from William (Bill) Gudenrath at the wood kiln glassblowers meeting in Velzeke, Belgium on September 7^th 2018

Dimensions: Height 24.7 cm, diameter cup: 8.2 cm, diameter base: 9.0  cm, weight 113 gram and capacity 181 ml, so lightness ratio (capacity in ml / weight in gram) 1.6

Condition: perfect, no signs of wear

Parallels: Number 29 in the collection Engels – de Lange. Comparable glasses are held in the British museum in London (Tait 1979, 55, p.54) (with later replacement stem), the Musée des Arts Décoratifs in Paris (Baumgartner 2003, 31, p.80-81) and the Corning Museum of Glass (Charleston 1980, 38, p.92-93).

Conclusions:

Characteristics such as color, weight, style, form, engraving, glass structure can all be used to pinpoint time and place of origin of a glass. But also traces of use, inclusions and weathering can be used in addition. The glass material changes over the ages with small degradations, looses a bit of it clarity and shows signs of use (even very small ones). The lightness ratio (i.e. the capacity in ml divided by the weight in gram) can be applied as a dating indicator too. The 16^th century venetian glasses are so thin that they are capable of holding up 3 times their weight, while the façon de venice glasses and the Salviati glasses have a lightness ratio of 2 or less.

Close observations of the colorless parts of the glass reveal a different structure for the three glasses. The Venetian glass from circa 1600 has a wealth of very small irregularities and the blue color is deep aquamarine. While the Salviati glass has the same irregularities but the color has no hint of any other color and the blue color is greenish. The Gudenrath glass has no irregularities and the color is clear with no other color what so ever.

However at a glance one can understand that all three glasses could wrongly be classified as renaissance Italian glasses.

The need for a none-destructive, none-invasive analytical method that can precisely measure the composition of the glass under study is clear. Some of the results of the XFR (X-ray fluorescence) method look promising however more standardization and a simple multivariate interpretation algorithm should be installed. Research to facilitate this was performed in the past by Karl Hans Wedepohl and in the present by Koen Janssens, however we are far from “a C14 method for glass”.

None of these glassblowers had the intention to deceive the user in any way, we believe. However copies, fakes and forgeries are also present within the trading world of antique glass.

References:

– Catalogo “Salviati & Company, Londra”, number 414 (shown in Aldo Bova (and others), Vetri artistici, Antonio Salviati 1866-1878, Museo del vetro di Murano, Venezia 2012, p.119)

– Het vormglas door de eeuwen heen. Collectie Bomers – Marres. Anna en Kitty Laméris, Frides Laméris Kunst- en Antiekhandel, 2006, page 51 (quotation)

– Kitty Laméris , the descriptions of the two first glasses (I and II), July 25^th 2016

– Karl Hans Wedepohl, Die gruppe der Hedigsbecher, Nachrichten der Akademie der wissenschaften zu Gottingen II. Mathematisch-physikalische klasse, 2005, nr 1

– Koen Janssens, Modern methods for analyzing archaeological and historical glass, Wiley, two volumes, 2013

– Paul Craddock, Scientific Investigation of Copies, Fakes and Forgeries, 2009, page 213

– Paola Ricciardi, Philippe Colomban, Aurelie Tournie, Veronique Milande, Nondestructive on-site identification of ancient glasses: genuine artifacts, embellished pieces or forgeries. Journal of Raman Spectroscopy, vol 40 issue 6, 2009, pages 604 – 617

ROMAN FLASK NATURAL GREEN GLASS

ROMAN flask from the Elisabeth & Theo Zandbergen collection

Dimensions: ↑ 12,9 cm.; largest body ø 4,8 cm.; ø mouth 5 cm.; weight 107,5 grams.

Origin: most probably Eastern Mediterranean, Syro- Palestinian, Date: ~ 4^th century AD.

Material: Soda glass, condition: intact.

Description: The body of this object made from darkish green glass has been pre-formed in a dip mold thru which the ribbing was formed. In the next steps the body was further blown out and the neck and the mouth were free formed. The body is slightly conical. The mouth of this object makes it a bit enigmatic. Normally these collar shaped mouths have a bottom forming a groove in which material from the flask could be held and for example be used as a kind of air freshener from the evaporating ethereal oils in that groove. Such groove is in this case only rudimentary present. Not enough to contain any fluid. As the “Romans” were quite practical in their approach in forming the objects taking into consideration the potential use or application of the object, one wonders about the reasons of this glassmaker to make such an elaborate mouth. It makes this flask, however, quite unique. Collecting is not a straight forward process as many objects carry let’s say some mysteries.

Parallels: (amongst others):

No direct parallels have been found as yet. For the body and color numerous parallels can be found of which some are listed below:

• Antanoras, Fire and Sand pg.93 nr. 110,
• Arveiller-Dulong & Nenna, Les verres antiques du Musée du Louvre.pg. 427 nr 1193,
• Ancient glass in the Carnegie Museum of Natural History, Pittsburg, nr.221,
• Rossum van H., Roman and early Byzantine Glass (2011) pg. 208 HVR 009,
• Groen van der J., Romeins glas , een privé collective (2018), pg. 262/263 – VDG 086, pg. 264/265 – VDG 059, the last one for the typical collar mouth,
• Zandbergen, Levend glas (2017), pg. 42/43 RF – 15, also for the typical collar mouth,
• Rossum van H., Romeins glas, collectie van Annelies Bos-Pette (2019), pg.156/157, ABP 048,

Provenance: – ex David Berman collection, Haifa; – Archaeological Center Ltd, Tel-Aviv.

THE VICTORIA AND ALBERT MUSEUM, GLASS COLLECTION HIGHLIGHTS

The Victoria and Albert Museum

The Victoria and Albert Museum, in London

V&A Museum’s Foyer with a Dale Chihuly glass sculpture in the center

 The Victoria and Albert Museum, London, is the world’s largest museum of decorative arts and design, housing a permanent collection of over 4.5 million objects. It was founded in 1852 and named after Queen Victoria and Prince Albert. The glass collection covers 4000 years of glass making, and has over 6000 items from Africa, Britain, Europe, America and Asia. The earliest glassware on display comes from Ancient Egypt and continues through the Ancient Roman, Medieval, and Renaissance covering areas such as Venetian glass and Bohemian glass and more recent periods, including Art Nouveau glass by Louis Comfort Tiffany and Émile Gallé. The Art Deco style is represented by several examples by René Lalique. There are many examples of crystal chandeliers displayed in the British and Venetian galleries attributed to Giuseppe Briati dated c1750. The stained glass collection is possibly the finest in the world, covering the medieval to modern periods, with examples from Europe as well as Britain. Several examples of English 16th-century heraldic glass are displayed in the British Galleries. Many well-known designers of stained glass are represented in the collection including, from the 19th century: Dante Gabriel Rossetti, Edward Burne-Jones and William Morris. There is also an example of Frank Lloyd Wright’s work in the collection and other 20th-century designers.

Most of the glass pictures below are from the museum’s own web site.

Alembic cap 19th Centure

Bavaria tankard 1655

Beaker (passglas) 1650-1720

Beakers from German early 17th century

Bohemia, Czech Republic beakers 1616

Bohemia, Czech Republic glass vessels 1599

Calcedonio glass from Venice 1500-1520

Egyptian core-form glass 1336 BC-1213 BC

Egyptian core-formed unguent glass jar 1400 BC-1336 BC

Enamelled glass bottle, with pewter mount 18th Century USA or Germany

Filigree glass goblet from Venice 1600-1725

Filigree glass tazza from Venice 1550-1650

Filigree vase, Venetian glass; 1550-1625

Flute from Netherlands 1575-1625

Footed bowl from Venice last quarter 15th century – early 16th century

Footed glass bowl from Venice 1475-1525

German drinking cup 1650 – 1675

German siphon glass 1650-1720

Glass beakers found in England 6th century

Glass tazza from Venice 1550-1600

Goblet from London, England 1586

Goblet from Venice 1500-1550

Goblets, Italy (Venice), made by Salviat 1866

Horn, Netherlands (probably Middelburg or Antwerp), 1550-1600.

Ice-glass beaker from Netherlands 17th Century

Islamic bottle, glass with wheelcut facets with central roundels, 900-1000, Iran

Islamic glass Mosque lamp, Mamluk Egypt, 1382-1400

Krautstrunk beaker from German 15th century-early 16th century

Onion shaped wine bottle, England, 1710-1730

Over view of Frankish and Merovingian glass 2

Over view of Frankish and Merovingian glass

Part of the main glass gallery room 131

Roman glass 1st-2nd century 2

Roman Glass 1st-4th Century

Roman glass bottle 2nd century

Roman glass late 2nd century BC-1st century BC

Roman juglet from Sidon 1st Century Unknown Collection

Rosewater sprikler (almorratxa), Catalonia, Spain, 1550-1650

Ruby glass goblet with cover from Bohemia, Czech Republic mid 19th century

Ruby glass set from Germany 1700

Sculpture in Glass from Scotland 1991

Spainish glass vessels 16th-17th century

Stained glass panel, depicting Christ’s resurrection, Germany, c. 1540–42

The Luck of Edenhall, glass beaker, Syria, 13th century

Tiffany Favrille glass from USA

Water jug from Spain 17th-18th century

Whitefriars Tumblers 20th century

Wine glass Roemer with Rassberry Prunts, probably Netherlands, possibly engraved by G.V. Nes, 1650-1690

Wine Glass Facon de Venise

Wine glasses (Roemers), Germany or Netherlands, 1625-1699

Wine glasses from England 1759

PATTERN-BLOWN ROMAN GLASS JUGLET

PATTERN-BLOWN JUGLET of Hans van Rossum

Date: 4th century AD | Eastern Mediterranean Size:↑14.0 cm | ø 4.1 cm | Weight: 52 g

 

Technique: Body pattern-blown, neck and mouth free blown; handle and coil applied

Classification: Kisa 1908: Band II, nr. 9, p. 317 for the type of the handles

Condition: Intact

Description: Transparent medium blue glass, elongated conical ribbed body tapering toward bottom, flat base with roughly cracked off pontil. Cylindrical neck and sloping shoulders, wide mouth and rim folded inward. The handle applied to the shoulder, drawn up and attached to rim, terminating in fold. Trail wound around neck.

Provenance: Jerusalem art market, Sasson Ancient Art Ltd. 4 June 2006 no. G-1225

Published:  Bonhams London, auction 26 April 2007, lot 240

Exhibited: Thermenmuseum Heerlen (NL), Romeins Glas, geleend uit particulier bezit, exp. no. 101 29 April – 28 August 2011

Reference: Les Verres Antiques du Musée du Louvre II, V. Arveiller-Dulong & M.D. Nenna 2005 nos. 1011 & 1143 Ancient Glass in the Israel Museum, The Eliahu Dobkin Collection and Other Gifts, Israeli 2003 no. 212

ROMAN GLASS BOTTLE WITH STRAP HANDLE

Bottle with Handle of Luduvic Deswelle Collection

Date: 3rd-5th Century Height: 23 cm Diameter: 12 cm

Description: Cylindrical bottle, light green color with golden iridescence.

Classification:  Isings form 126

Parallel: Glass in The Corning Museum of Glass Vol. I, David Whitehouse, 1997 number: 329

 

THE ROMAN GLASS GRAPE FLASK

Roman Grape Flasks

Grape Flasks are a type of Amphorisko used for liquids. They are decorated with a mold-blown cluster of grapes usually identical on both sides with a seam indicating where the two sides were joined. They were made in Syria, Italy and Gaul, in the first to third centuries. For this pictorial we are dividing grape flasks into three types: Realistic, Stylized and Flasks with Handles. The examples below are from private collections and museums.

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FLASKS WITH HANDLES

Yale Art Museum

St Germain, Archeological Museum

Metropolitan Museum of Art

Romisch-Germanisches Museum, Cologne

St Germain, Archeological Museum

Yale Art Museum

Metropolitan Museum of Art

 

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REALISTIC FLASKS

New Orleans Art Museum

Nico F. Bijnsdorp

Toledo Art Museum

J. Paul Getty Museum

J. Paul Getty Museum

 

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STYLIZED FLASKS

Hamilton College

Joop van der Groen

The Windmill Collection of Roman Glass

Metropolitan Museum of Art

Toledo Art Museum

Metropolitan Museum of Art

Brooklyn Museum

Brooklyn Museum

 

 

ROMAN COLOR-BAND MOSAIC GLASS BOTTLES

COLOR-BAND MOSAIC GLASS BOTTLES

Roman cast and blown color-band mosaic bottles are a type of small to medium-sized containers designed to hold perfumes, scented oils, or other substances. All representatives of the class have polychrome bodies and were manufactures on a blow pipe using the inflation technology introduced in the Augustan and Julio-Claudian periods 44 BC-69 AD.

Remarks: This class of bottle is important because it combines free-blowing with preformed cast mosaic elements. It also documents the crucial transition from an industry predicated on monochrome and mosaic casting to one based almost exclusively of free and mold-blowing and marks the beginning of a new Roman industry. (Above taken from, Early Ancient Glass, David Grose, Toledo Museum, 1989)

J. Paul Getty Museum

Corning Museum of Glass

Corning Museum of Glass

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How a color-band glass bottle is made by William Gudenrath