Author Topic: Opalescent Art Glass Basket  (Read 3869 times)

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Offline Lustrousstone

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Re: Opalescent Art Glass Basket
« Reply #10 on: March 04, 2008, 07:09:33 AM »
I've had another closer look and without handling it, I would guess that the handles weren't applied afterwards. It doesn't look like hand tooling to me. It's supposed to look like they were separate because that's how basket handles are. If you flatten it out, it's just a bowl/plate with two loops on either the side.


Offline Bernard C

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Re: Opalescent Art Glass Basket
« Reply #11 on: March 04, 2008, 09:44:15 AM »
Quote from: krsilber
... I'm curious why people are saying this is pressed.  When I think of pressed, I think of a mold and plunger, and I haven't seen anything that suggests that is necessarily the case here.  Since plungers have to be smooth in order to remove them after pressing, the pattern of the rope rim couldn't have been formed on the inside during the pressing process. ...

krsilber — No, the only requirement of moulds is that what is being moulded can be removed — and reasonably easily then, when the glassmakers were paid piecework rates.   Smoothness of the plunger is conventional on tableware, where hygiene is important, but even that is sometimes not the case, as trademarks and registration symbols are often found punched into the mould on the smooth, plunger side.   Pressed glass baskets of this style were pressed flared, so any amount of ornamentation could be cut into the plunger, including inner rim ropework.   Once the basket was removed from the mould it was reshaped either by hand or by the use of one or more formers to achieve the final closed shape.

If you look closely at Ken's latest photographs, you will see the mould line (the junction of the plunger and the side components of the mould) running along the top of the ropework rim of this fascinating basket.

The reason I suggested a two stage process, along the lines of the J.G. Sowerby patent, was that you never get a perfect join between the first stage, separately pressed "ornamentation", here the handles, and the main object.   You will see the same effect with incalmo joints, with ribbon cloud on the outside near the base, and on some examples of malachite or "slag" glass, where you can run your fingernail along the joints.

BTW — Apologies, I had to ask — Are you a descendant of the Silber of Silber & Fleming, whose c.1890 mail order glass and china catalogue is so useful to us today?

Bernard C.  8)
Text and Images Copyright 200414 Bernard Cavalot


Offline Lustrousstone

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Re: Opalescent Art Glass Basket
« Reply #12 on: March 04, 2008, 10:22:57 AM »
The more I think about this basket, the more I wonder if it is newish (relatively speaking that is). The acanthus leaf seems overfrilled and what about the pink colour of the opalescent bit under a UV light. That must be a clue to the glass composition but I don't have any opalescent to compare it to


Offline Ohio

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Re: Opalescent Art Glass Basket
« Reply #13 on: March 04, 2008, 06:02:53 PM »
Christine I'm a bit skeptical with 36 years of glass collecting/selling experience, athough granted the vast majority has been US based art glass, that the basket/bowl is relatively recent. It has all the earmarks/traits of items produced (whether English, French or Bohemian) during & up to the late 1800's to early 1900's. Now on the reaction to the blacklight, yes I agree it all varies with the chemical composition of the formula & I have seen/experimented with different reactions for years. Case in point: Henry Hellmers is considered by many to be the Godfather of American glass chemists (I won't bore by naming them all) & from 1930 to around 1955 Henry developed more than 1,000 formulas, many of which contained one or more of the reactive Uranium Oxides although in the early years they are simply listed as Uranium. The National Cambridge Collectors has a listing of many of his formulas & as an example a batch of light Emerald which weighs in at 1,422 lbs (US) only 2.68 lbs are reactive Uranium Oxides combined with Arsenic, Copper Oxide, etc. & the reactions vary formula to formula, e.g. a batch of Willow Blue that also contains the reactive oxides does not produce the same reaction under blacklight due to chemicals that differ in that particular mix. I've seen blacklight reactions that vary from the traditional greenish glow to yellow, orange, pink/volet, etc. I'm not a glass chemist, but I've often wondered what chemicals affects included in the mix causes what reactions? Why do compositions which may include, Bichromate, Copper Oxide, Red Lead, Borax, Manganese, Tin Oxide, Antimony Oxide, etc, etc, react differently when paired with the traditional Uranium Oxides? It's a question that probably only a scientist using a Spectrometer could answer, I can say though that I'm not suprised at seeing orange, pink/violet, or any other hues in what I've tested during the years.  Ken


Offline Frank

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Re: Opalescent Art Glass Basket
« Reply #14 on: March 04, 2008, 07:15:36 PM »
The colour of any reaction will inevitably change as the composition changes only those molecules that fluoresce will emit light but there are other compounds that absorb parts of the spectrum. I would expect some detailed studies of these reactions have been made by the various Glass Technology groups around the world - you could try contacting them directly or search through the Rakow Library catalogue for scientific papers on the subject. Probably dry reading but could be interesting. I doubt much has been published outside of journals.

Some examples that will be on file at least at SGS Sheffield is:

Fluorescent Phenomena.
Published in Transactions of the Optical Society 1919-20 #21, 219
Abstract in Journal of the Society of Glass Technology 1921 #5

Nichols, Edward and Merrit, Ernest did a specific study on Fluorescence of Canary Uranium Glass. "Studies in Luminescence" Physics Review 1904 #19 18-36

Patents are another path to some data, see US 1629248 May 1927 Uranium red glass.

As the date is before these things were fully understood probably an absorbable account. Moden papers can get very esoteric. Duncan lists many titles relating to this area. Not surpisingly most of the earlier studies were in German
Frank A.
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Offline krsilber

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Re: Opalescent Art Glass Basket
« Reply #15 on: March 05, 2008, 12:40:12 AM »
Wow, fluorescence, another of my favorite topics!  This basket or yours, Ken, has raised all sorts of interesting issues.

"No, the only requirement of moulds is that what is being moulded can be removed ... Once the basket was removed from the mould it was reshaped either by hand or by the use of one or more formers to achieve the final closed shape.

Of course, why didn't I think of that.  The outside of the mold can be removed, and the object pried away from the plunger to retain the patterned edge.  I'm so used to thinking about pressed glass as having minimal post-mold manipulation, but that's obviouly not always the case.

"....you never get a perfect join between the first stage, separately pressed "ornamentation", here the handles, and the main object."

The handles sure look well-joined to me.  Isn't it possible they were pressed at the same time the basket was made? 


Out of curiosity, has anyone seen any glass from the Victorian era or earlier that glowed pink/purple like this?

I'd sure like to get my hands on those articles Frank mentions!  And a spectrometer.  Shortwave UV light, Geiger counter...Heck, I want a whole lab!

 
Kristi


"The most beautiful thing we can experience is the mysterious. It is the source of all true art and all science."

- Albert Einstein


Offline Ohio

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Re: Opalescent Art Glass Basket
« Reply #16 on: March 05, 2008, 06:10:12 AM »
Kristi I had a Harlequin AKA Quadruple Diamond opalescent vase that was attributed in Edwards & Carwile Standard Encyclopedia of Opalescent Glass, a relatively recent 5th edition reference. It was attributed as English, wheter or not that was accurate I cannot say, but the reaction was identical, a pinkish/violet glow. Unfortunately I sold it in January 2008 & purged the jpg when I finally got around to reorganizing all the jpgs on my server.  Ken


Offline Lustrousstone

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Re: Opalescent Art Glass Basket
« Reply #17 on: March 05, 2008, 07:31:38 AM »
I wasn't saying it was new, it was more a thought thrown into the melting pot that perhaps it wasn't of the Victorian era. I am also unsure that there would be uranium in the white opalescent glass. It's a pretty basket and could come and live at my house any time - it fits the uranium criteria with its leaf  ;)


Offline Frank

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Re: Opalescent Art Glass Basket
« Reply #18 on: March 05, 2008, 08:32:28 AM »
The pinkish colour is merely the reflected 'visible' radiation from the UV source. With a fine spectrum UV source (with no visible light) only fluorescence would be seen - the rest would be black. Lamps are available in the reprographics world but are lethal to the eyes.

Spectroscopy see Mrvaselineglass in http://www.glassmessages.com/index.php/topic,4389.msg36479.html#msg36479

and also check out some ideas in Martins posts here http://www.glassmessages.com/index.php/topic,18737.0.html
and for a more ambitious low-budget approach http://home.freeuk.com/m.gavin/grism2.htm

SG see http://www.glassmessages.com/index.php/topic,18907
Frank A.
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Offline Ohio

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Re: Opalescent Art Glass Basket
« Reply #19 on: March 05, 2008, 03:39:55 PM »
Hi Christine, yes by definition of Victorian 1837-1902 it could be later, maybe all the way to 1915 or so. It's simply a decent example of a whimsey. Frank, interesting discussion on the Uranium in glass. I liked the part on the hazards of working in a glass house in those times. No doubt if various governmental Occupational Safety & Health operations were in operation back then we never would have had any glass to admire today.

 

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