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71
Glass / Re: Do I not understand? Lead in glass a barrier to fluorescence of uranium opaline?
« Last post by flying free on March 27, 2023, 08:33:07 PM »
ok, I vaguely follow that Sue :)  Thanks for taking the time to explain.

I think the article in Pressglas-korrespondenz was trying to make a point though about using uranium oxide in lead glass.
Was it perhaps about making an opalescent or opaline effect with uranium and that in lead glass the lead stopped that effect happening maybe?   The article appears to indicate that there was no interest in using uranium oxide in lead crystal batches but did it mean only in the instance of opaline/opalescent effect.  Could it be that the opalescent or opaline effect didn't happen in lead glass thereby indicating that opalescent uranium glass or opaline uranium glass is only found in Bohemian non lead glass.

It's trying to make a point but I don't know which point :)  I suppose it could be the explanation as to why there may be no opaline/opalescent uranium glass French opalines (lead glass) but only Bohemian ones (non-lead glass)?  I don't know if that's true btw but I don't recall seeing any (not that my list of viewing is exhaustive at all though).

John Ford seemed apparently happy with his uranium oxide in lead glass outcome. 

72
Glass / Re: Do I not understand? Lead in glass a barrier to fluorescence of uranium opaline?
« Last post by chopin-liszt on March 27, 2023, 08:23:07 PM »
The weakly radioactive alpha particles have enough energy to shift the wavelength of light you are using,(uv) into the wavelength of the glow (green) you see.
That is what radioactive fluoresence is.
Fluoresence is not a property of uranium, per se.
The lead will block the particles from progressing, but they do not stop what the uranium is doing itself.
(I'm being pedantic about you saying the lead stops it from fluorescing, m, 'cos it doesn't, not really.)
Fluoresence is the shifting of the light from one (dullish) wavelength to the brighter one.
It sort of happens inbetween the item, the light source and your eyes.

There are other non-radioactive chemicals which are fluorescent. eg fluorescene.

73
Glass / Re: Do I not understand? Lead in glass a barrier to fluorescence of uranium opaline?
« Last post by flying free on March 27, 2023, 08:01:51 PM »
Thank you both :)

So if it turns out to be correct that lead stops uranium fluorescing then for the sake of debate I might reasonably assume that the V&A QV bowl was probably made with unleaded glass.  Which means if it was made here it in 1837 it would have been made by a maker using non lead crystal in the batch.  I wonder did they routinely make up both a leaded crystal for clear cut glass and a non leaded batch for particular reasons to do with colour?

Or did they just add uranium to the lead batches, to create a colour. They wouldn't have known about the fluorescence at that time would they?
See John Ford recipe here:
https://www.glassmessages.com/index.php/topic,70066.msg403520.html#msg403520
74
Glass / Re: Do I not understand? Lead in glass a barrier to fluorescence of uranium opaline?
« Last post by chopin-liszt on March 27, 2023, 07:39:20 PM »
The fluoresence arises from the radioactive component of the metal.
There are three isotopes of uranium, U-234, U-235 and U-238. Only the latter two are radioactive, and neither is terribly strong, they are just alpha emitters. A weak source, easily stopped with a sheet of paper. Only harmful if ingested.
(This is a very simplistic explanation. Other isotopes can be created and we are not talking about depleted uranium which is the really dangerous stuff.)

You might be aware that lead lined boxes are what radioactive stuff is kept in? Lead stops even stronger activity than Uranium.
I imagine lead in the glass might have the same shielding effect.

Anne and me cross-posting.  :-*
75
Glass / Re: Do I not understand? Lead in glass a barrier to fluorescence of uranium opaline?
« Last post by flying free on March 27, 2023, 07:31:50 PM »
I will Anne and thanks so much for the link :)

I suppose  my basic query is whether that uranium glass QV bowl could have been produced in Britain or was it  produced by a Bohemian maker not using lead in their batch. i.e. did all the big makers here use lead in their batch in the 1830s?

Or - like John Ford, were they using uranium in lead glass batches anyway?  to create a colour, as they wouldn't have known about the fluorescence really then.
https://www.glassmessages.com/index.php/topic,70066.msg403520.html#msg403520
76
Glass / Re: Do I not understand? Lead in glass a barrier to fluorescence of uranium opaline?
« Last post by Anne on March 27, 2023, 06:20:32 PM »
My reading of it would be that lead in crystal prevents the uranium from creating the familiar uranium glow we see in non-lead glass. This would make sense as lead was (still is?) used to line containers in which uranium could be stored to prevent radiation contamination, so perhaps the lead in the crystal somehow prevents the uranium from doing its stuff?

It might be worth using the Ask a Question service at CMOG / Rakow Library as they have someone who seems able to answer this type of question, see here https://libanswers.cmog.org/faq/143932
77
Glass / MOVED: perfume bottle
« Last post by Anne on March 27, 2023, 06:08:04 PM »
This topic has been moved to Scandinavian Glass.

http://www.glassmessages.com/index.php?topic=72610.0
78
Scandinavian Glass / Re: perfume bottle
« Last post by glassobsessed on March 27, 2023, 04:47:55 PM »
Yes it is, listed in the 1965 Retail Price List as Flacon, with the engraved design it is numbered 636/1173 costing 27 Dollars US at the time. There is also a 636/cut, presumably with a cut pattern instead which retailed for a bit less. Hoglund did a fair few figural designs.

John
79
Glass / Cased glass candle holders
« Last post by lambden on March 27, 2023, 04:28:30 PM »
Can anyone help with these, I have e never seen anything like it. Very well made with a spring candle.
80
Glass / Re: Fused sphere surface decoration query.
« Last post by Ekimp on March 27, 2023, 03:49:23 PM »
Yes, pleased with that :)
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