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Author Topic: ID help with classical style vase please  (Read 31160 times)

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Offline Paul S.

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Re: ID help with classical style vase please
« Reply #100 on: January 29, 2013, 10:03:49 AM »
sorry meant to add that, for my money, these have nothing to do with opaline  -  I see them as simply opalescent.

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Offline Paul S.

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Re: ID help with classical style vase please
« Reply #101 on: January 29, 2013, 10:14:59 PM »
Out of interest, the following entry is in the glossary of Colin Lattimore's book** on pressed glass...........
"opaline:  An opalescent glass produced by the addition of cryolite or arsenic to the batch.     Appears milky by reflected light and shows many blue and golden tints by transmitted light".

Contrary to my earlier comment re finger bowls, I'd overlooked the fact that I have this opalescent example in turquoise.
Which of the oxides has been used to colour the glass I'm not sure, but it might have been copper, or perhaps the most tinsiest bit of cobalt. :)

Ref.    'English 19th Century Press-Moulded Glass'   -  Colin R. Lattimore  -  1979

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Offline flying free

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Re: ID help with classical style vase please
« Reply #102 on: January 30, 2013, 01:15:32 AM »
Paul, thank you for posting the quote /references and your pictures:) both your bowls are just superb.
 
I don't know if I can agree with his (Lattimore) definition as a current definition.  In one sense it is a very 'pure'  definition, I think matching the Counts(i.e when opaline glass was first invented and bone ash and/or arsenic were added to the batch as the opacifier, producing a semi translucent glass that was opaline and had an opalescence - see the Count's definition/description and the 1832 recipe)... and so yes I do agree with it in that sense.

However, it does not take into account the developments over time, of 'a glass which has been coloured by adding an opacifier to the batch, such as bone ash or tin oxide or phosphate of lime etc which, when cooled, becomes semi-translucent’ – That is, some of that glass is semi translucent (opaline) but not opalescent depending on what has been added  to the batch as an opacifier.
 I've based that opinion on the fact I have had a few pieces of French opaline glass which did not display the opalescence, and certainly have opaline glass from other countries that does not either and also the pictures from the Clichy book.

It comes back each time to
-   Has opaline glass changed over time in the way it is made?
-   Or have definitions changed over time? 
-   What exactly would be the definition of opaline glass?

It is only my opinion, but from all the pictures and references we have been through, my thoughts are:

a) Opaline glass has changed over time in the way it is made, in that the opacifier has changed.  Meaning it no longer always has opalescence, as it did when bone ash/arsenic was used, but is still a 'glass made with an opacifier in the batch, which when cooled gives a semi-translucent effect',

b) The definitions for opaline glass have changed over time to account for this (e.g. Mehlman V the Count)

c) The definition of opaline glass needs to encompass opaline glass which is ‘flat’ i.e. has no opalescence and also that which is opalescent.

But I also have been thinking (and these thoughts I’m sure are going to be controversial and are up for discussion :)  )

-    Opalescent or opalescence is an effect in or on glass but is not a type of glass.
and that is why I can't find any definitions in books or online for 'Opalescent Glass...'


The reason for the thoughts above are that I have also been musing on the following (again these are just my thoughts and open to correction and discussion :) )

That there are three types of glass created in the batch:
-  Transparent   (Adjective (of a material or article) Allowing light to pass through so that objects behind can be distinctly seen )
- Translucent   (Adjective (of a substance) Allowing light, but not detailed images, to pass through; semi-transparent)
- Opaque          (Adjective Not able to be seen through; not transparent)

So for example;
-    flint, or amethyst or cranberry glass or any colour transparent glass would fit under ‘Transparent’
-   the examples of milchglass or lattimo or hyalith or lithyalin [ * ] (just a few I could think of) would all fit under ‘Opaque’
-   opaline glass would fit under ‘Translucent’

[ * ] Mod: Please see correction comments in post 109 below.

but opalescent glass does not fit under any of the types because it is not a ‘type’ of glass but an ‘effect ‘ in or on glass …  so
it can be an effect on or in  translucent, or opaque or transparent  glass depending on how it is created,

i.e. whether it is an effect created:
- in the batch (the effect seen on some translucent glass i.e. opaline glass (and also girasol which I also think is a  type of opaline glass) and possibly also opaque glass made using bone ash.   Lalique opalescent glass would come under this I think (**see below).
or
- as an effect of cooling and  reheating e.g. on the edges of transparent glass in the case of Pearline,
or
-on glass blown  into a raised patterned mould in two layers, and where the outer layer is translucent (opaline) made using bone ash and /or arsenic as an opacifier and so on reheating the outer layer on the raised pattern becomes opalescent.

** Source - ' Rene Lalique & Cie  The Complete Illustrated Catalogue for 1932'
In the English translated introduction in this catalogue Gabriel Mourey says
'...Whether he chooses for his material colorless, polished or frosted glass, opaline glass or colored glass (black,smoky,jade-green, sapphire blue, red, rainbow; whether he uses the technique of molded or cut glass, or combines these two processes, his imagination knows no limits....'   
In the original French paragraph he calls it '...le verre opalin' - there is no mention of opalescent or opalescence as far as I can find.

These are my thoughts :)
I would welcome contributions and discussions and to whether or not they make sense :)

                     With regards the definitions of opaline glass over time -

I think it is important to find early descriptions written when the glass was first developed, as well as descriptions over time, and the ‘more  recent’ descriptions looking back, if you see what I mean, as there are discrepancies between what is described as  opaline glass now and what was then,  from the sources we've referenced so far.

(And I have not been able to find an early reference to something called 'opalescent glass' in those sources?  or have I misremembered? Have you come across anything called 'Opalescent glass' or is it all 'Opaline glass that has opalescence' type descriptions? )
 
However,
 I have been searching early- mid 19th century French books and I have found another description written in France in 1853
 It’s quite a small piece,  interesting, but difficult to 'interpret' what is really meant by it:
Source: There were a number of editions of this book called
'Manuel complet du verrier et du fabricant de glaces '
by M. Julia de Fontenelle and Francois Malpeyre

In the one of 1829 there is no mention of opaline glass or opalescent glass except under mention of sapphire blue glass where they discuss in one part about the blue having an opalescence ( I think)
However in the 1853 edition there is a description headed:
'Verre opalin ou opalescent'   (Opaline or Opalescent glass)
It reads as follows (translated by Google translate - original below without 'accents' unfortunately)

This is a milk glass resembling the alabaster or opal that has prepared the way ordinary, with the addition of
a greater or lesser quantity of calcined bones.

It goes on to talk I think about making opaline uranium glass (I think talking about that uranium opaline glass can be created instead of opalescent opaline glass ...but don't quote me on that as I found it quite hard to understand exactly what was being described)
-

Glass can be manufactured in a top quality with a greenish reflection with the following mixture
calcined bones
yellow oxide of uranium
forge slag

It is claimed that the colored glass mixture with previous change of color under the influence of sunlight and we can prepare a glass of a color more beautiful and withstood the action of the sun by substituting nickel oxide in forge slag


So it seems to me that, written in 1853 in France, this appears to be describing a type of glass and calling it ‘either opaline or opalescent’.  It is the first time I’ve come across a description naming ‘opalescent’.
Still investigating, but I think at the moment I would still call your both your bowls and the pieces from the Bonhams link, opaline glass :)
jmpov though.

French original from book above (missing accents, my lack of keyboard knowledge sorry)
'C'est une verre laiteux ressemblant a l'albatre ou a l'opale qu'on prepare a la maniere ordinaire, avec addition d
'une quantite plus ou moins forte d'os calcines. On peut fabriques le verre d'une qualite superieure avec un reflet verdatre avec le melange suivant
os calcines
oxyde jaune d'urane
scories de forge
On pretend que le verre colore avec le melange precedent change d couleur sous de influence des rayons solaires et qu'on peut prepare une verre d'une couleur plus belle encore et que resiste a la action du soleil en substituant l'oxyde de Nickel au scories de forge'


As I said, all up for discussion :) and these are just my thoughts :)
m

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Offline flying free

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Re: ID help with classical style vase please
« Reply #103 on: January 31, 2013, 11:13:53 AM »
Source reference and quote  for my comment on girasol glass being opaline - here on the Museo del Vetro website under the heading of Opal Glass
http://museovetro.visitmuve.it/en/il-museo/percorsi-e-collezioni/the-arsenale/the-arsenale/

'Opal glass (Girasol or Sunflower). Opalescent glass with an orange sheen, more matt than opaline, introduced into Murano technology since 1693. This glass is slightly opaque due to the presence of lead hydrogen arsenate crystals in the glassmaking mixture, that due to their size confer an original colour to the glass, which appears bluish when observed under reflected light and light brown, or pink, when observed under direct light. In the 1800s, this type of glass was presented by Salviati & C. at the Industrial Exhibition at the Doges’ Palace in Venice. On that occasion abbot Vincenzo Zanetti wrote “Opaline glass, which after repeated and very expensive experiments was finally obtained in Salviati’s laboratories due to work on glassblowing in all security and a very beautiful quality, was one of the most reluctant to mingle with other colours. In our opinion it must have been so also in the past, as it is true that the ancients knew very well how to produce the lovely opaline paste and wrought objects of diverse forms, but such objects of past ages, which are not found profusely and that are therefore paid fantastic prices, are not pure, meaning without other colours. Well, Salviati was the first to show us this lovely glass merged and decorated with any other paste and even with ruby and with aventurine itself. …” (La Voce di Murano, 18 July 1868, N°. 28, pages 117-119).'

Source reference link regarding the intro from Gabriel Mourey on the Lalique Complete Illustrated Catalogue 1932 (please see English version and French version for my comments above)
 http://books.google.co.uk/books?id=AnunJp1VfS0C&pg=PT12&dq=lalique+opaline&hl=en&sa=X&ei=QY4HUaXdEI610QX23oGQAw&ved=0CEQQ6AEwAzgU#v=onepage&q=opaline&f=false

m

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Offline flying free

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Re: ID help with classical style vase please
« Reply #104 on: February 02, 2013, 03:50:05 PM »
and a good article here on the Roland Dufrenne site which explains the transition from transparent opaline with opalescence to the less transparent over time - the  period mentioned being 1820-1860.  The pictures speak for themselves and the first picture is clickable so it can be enlarged to show how translucent the early opaline was as well as the opalescence on it.
http://www.rolanddufrenne.com/les-opalines/

Using google translate the translation of the article reads as follows:

'Originally, in ancient times, glass was opaque. From a close look of porcelain, it was used in imitation of some precious stones.
From the fifteenth or early sixteenth century Venetian glassmakers produced a white opaque glass called lattimo inspired the porcelain of the Far East which the method was unknown in Europe.
This glass was obtained by the addition of lime and tin composition.
In the early nineteenth century, appears crystal opal or opaline crystal, more or less transparent, milky appearance soap or obtained by the addition of phosphate of lime (calcined bones).
The crystal created in the second half of the eighteenth century, Vonèche, St. Louis and Montcenis, be the first to make crystal opal, but the first half of the nineteenth century saw the creation of more high-quality crystal, including the crystal Choisy-le-Roi (1820), Bercy (1826), Lyon-Guillotière (circa 1839) and Clichy (1842). The first two produce most of the beautiful opal crystal opal we now call Restoration period or Charles X. The opaline crystal comes in several pastel colors: lavender, turquoise, pink "pigeon-throat", ultramarine blue, amber and green jade.

Glass of water opaline blue (1850)
In 1844 began production of opaque glass with vivid colors (blue flag, green chrysoprase, pink, lemon yellow) plus a semi-opaque white, slightly gray, called "rice paste" or "alabaster" such opaque glass produced by all the major crystal under the Second Empire, is now known as opaline, name and adopted by the widespread trade in antiquities in the early twentieth century.
Manufacture of opal with bright colors reached its peak between 1850 and 1860, it decreased significantly at the end of the Second Empire.
'

m

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Offline flying free

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Re: ID help with classical style vase please
« Reply #105 on: May 27, 2013, 01:14:05 AM »
Research article and documentation  on the making of opaque Venetian glass 15thc to 20thc and the use of opacifiers/which opacifiers were used when. 
I've used an automatic translator - it should allow you to click the translate box at the top and do an automatic translation
'Les verres opaques :la technologie des verriers vénitiens (XVe-XXe siècle)'
Authors:

Cesare MORETTI ,
Chemist, Technologist Verrier
S.Vito al Tagliamento (Italy)

Sandro HREGLICH
Researcher
Stazione Sperimentale del Vetro, Venice (Italy)

http://www.verre-histoire.org/colloques/innovations/pages/p202_01_moretti.html
m

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bfg

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Re: ID help with classical style vase please
« Reply #106 on: May 28, 2013, 07:22:35 AM »
thanks for posting it m, I'll have a read  through tonight

Mel

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bfg

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Re: ID help with classical style vase please
« Reply #108 on: November 07, 2013, 11:30:36 AM »
thanks m, just noticed that this thread had moved up again (no notifications) I'll get back when I've caught up  :)

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Offline flying free

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Re: ID help with classical style vase please
« Reply #109 on: January 14, 2014, 11:28:14 AM »
A correction to my post 102 further up the thread (see quote below from that thread and I've underlined the relevant part).  In that thread I mentioned that in my view Lithyalin would fall within the group of opaque glass.  This is not true.  Lithyalin as far as I can deduce, is an effect on glass of making it look marbled.  Originally (again as far as I read), it was done on hyalith glass, but I have also found Lithyalin glass done on translucent glass.

'The reason for the thoughts above are that I have also been musing on the following (again these are just my thoughts and open to correction and discussion :) )

That there are three types of glass created in the batch:
-  Transparent   (Adjective (of a material or article) Allowing light to pass through so that objects behind can be distinctly seen )
- Translucent   (Adjective (of a substance) Allowing light, but not detailed images, to pass through; semi-transparent)
- Opaque          (Adjective Not able to be seen through; not transparent)

So for example;
-    flint, or amethyst or cranberry glass or any colour transparent glass would fit under ‘Transparent’
-   the examples of milchglass or lattimo or hyalith or lithyalin (just a few I could think of) would all fit under ‘Opaque’
-   opaline glass would fit under ‘Translucent’
'

m

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