Topic: Royal Embassy Ware Czechoslovakia - Mystery set #113

[Ekimp]

Hi, I don’t know much about them and from the article it sounds like you have to get the right type to help avoid false readings. There is a buyer’s guide here if that’s any help:
https://www.imagesco.com/geiger/buying-a-geiger-counter-pg1.html

[NevB]

Thanks for that Ekimp, it does mention fiestaware ceramics collecting in the introduction but after that it's pretty generalised. It does look as though a fairly inexpensive hand held digital one would be OK, I'll investigate.

[theElench]

I know little about the science behind the phenomena that causes some glass to glow and would appreciate any opinions on my earlier photos and use of the camera to determine whether the glow is caused by Uranium or not.

What I see are two bowls (the Bagley and 113) that glow with much the same level of intensity and where the difference can be accounted for by the amount of Uranium present.   Importantly the photos accurately show the glow as seen with my eyes.

The other two (the Davidson and Inwald) glow with a completely different level of intensity and more importantly, when photographed, the pictures do not accurately show what is seen by the eyes.  Visually, both of these glow brightly enough that they might be thought to contain some Uranium, but the camera cannot capture it.

Could this be something to do with the wavelengths of the glows?  Whether it is or not it seems to me that the photos and how accurately they reflect what is seen by the eye is a simple test of whether or not a glow is caused by Uranium.

In other words, if the 113 bowl does not have some Uranium content, it would photograph like the Davidson or Inwald pieces and not like the Bagley bowl??

[NevB]

There is a very good article on the Collectors Weekly website by Ben Marks called "These people like to collect radioactive glass, are they mad?" It explains the science behind the uranium glow. I can't give you a link to it but if you go to their title page and scroll down the articles you should find it.

[Mod:Direct link to the article, as at 24 June 2020
https://www.collectorsweekly.com/articles/these-people-love-to-collect-radioactive-glass/]

As for the manganese question, I think it's like Christine said that manganese was initially put in a master batch of glass to get rid of any green tint caused by Iron Oxide. A colourant would then be added to produce whatever colour was required. This would mean all glass, including uranium glass, would also contain manganese. I'm not sure if the Davidson and Inwald pieces are uranium as they do pick up some of the glow from the pieces next to them. I don't know the science of the photography but I've had the colour of pieces change completely from the naked eye to a camera and again to a laptop. 

[theElench]

Thanks for your reply.  I read that article a few years ago when I realised how much Uranium glass I had collected (without knowing it) and was a bit worried that it might be a health hazard.  I found it informative, very re-assuring and would recommend it to anyone wanting a guide to Uranium glass.

I'm equally lost when it comes to the science of photography or the science of Uranium glass.  But that is the point I'm trying to make, a simple, practical test for Uranium glass which is science-free and relies solely on the images produced by my (basic) camera. 

It doesn't matter if the colour changes from the eye to camera, or from camera to lap-top.  The question is whether the camera accurately reproduces the intensity of the glow or not.

My photos of the Bagley and 113 bowl accurately show what I see, including that the 113 bowl's glow is weaker than that of the Bagley.  I would also point out that those photos were taken with the same set-up as the photos of the Walther "Rosen" bowl (in another thread) which was accepted as Uranium glass.

My photos of the Davidson and Inwald pieces are inaccurate (whether or not they pick up some of the glow through proximity to the pieces next to them) because although they appear in the photos to glow very weakly, (hardly at all in the case of the Davidson bowl) to the eye the glow is stronger, is clearly visible to the extent that for some time I thought the Inwald bowl was blue Uranium glass.

The photos show two entirely different reactions to the same UV light-bulb and I have very little doubt that the Rosen, Bagley and 113 bowls all contain Uranium.  Whereas the other two pieces do not.

[NevB]

I don't know if this will help but this first photo is of an old clear half-pint glass which definitely has manganese in it. You'll notice it only glows really green in the thicker parts and hardly at all elsewhere, the glass also becomes opaque around the green area. I think uranium glass seems to be a consistent colour all over. The second photo is of four trinket sets which show dramatically different fluorescence under the same amount of UV but I am sure are all uranium. You might try and find an old beer glass to act as a reference, they do still turn up, look for one with an excise stamp preferably with a pre 1953 GR mark.

[Ekimp]

I don’t know much about photography either, but the apparent brightness will depend on the exposure and what part of the frame the camera’s light sensor is looking at to calculate exposure, the brightness of other objects in the frame etc. I assume that’s the reason your 113 item looks brighter in the last two photos, so you would have to be consistent.

Even if you had a setup that was repeatable, unless you do some sort of chemical analysis/use a Geiger counter etc, then you are calibrating your system with items on which you have made assumptions. Skelcher says fluorescence is not necessarily proportional to % uranium content.

Your system might be right 90% of the time but if Skelcher is correct, you’ll miss the exceptions. Unless someone can disprove Skelcher then I don’t see how you can judge it accurately, when there is a weaker glow, just by looking at it.

Judgements on manganese/uranium in other threads showing items with a weaker glow seem to be based on colour but I’m not persuaded due to the problems NevB mentions with digital imagining.

[theElench]

Thank you Nev for those photos, I can see what you are getting at and agree with you that all the sets are Uranium but the glass isn't.  I'd draw your attention to the ("Mary"?) set at the bottom left corner and how the glow appears stronger on edges where the glass is thicker, just as the 113 pot does.

But I can also understand in a non-technical way, what Ekimp is saying re. the light sensor.  My lack of photographic knowledge means my camera is on auto-settings.  So although my set-up may be virtually identical in all the photos, the camera could well be adjusting according to what it is "looking at".

Something I've also noticed sometimes when taking pictures of pieces (nothing to do with Uranium glass) and have to resort to a bit of trickery to get the sensor to co-operate.

I think I should put my idea of a "quick practical test" back in its box and go back to the drawing-board, at least until I can explain it convincingly by backing it up with some supporting technical photographic know-how.  But thanks again for raising points that test my idea.

[NevB]

The two front sets are both by Libochovice, 1760/1670? on the left and 1700 right, both presumably made about the same time but each with a very different glow. I use a Nikon Coolpix camera in Auto mode, Macro mode for close ups and with the flash off for UV lit photos.

[Simba]

Has anyone come across this company..Royal Embassy Ware Czechoslovakia....they appear to be the makers or retailers of this mystery set... https://www.rubylane.com/item/712792-191RL7/Vintage-Embassy-Ware-Czech-Amber-Glass