Author Topic: Scotia paperweights  (Read 505 times)

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Offline Roger H

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Scotia paperweights
« on: October 01, 2012, 10:24:45 PM »
Can anyone tell me the long and short wave colours of the glass that the WM scotia weights were made of please.
      Regards Roger.


Offline tropdevin

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Re: Scotia paperweights
« Reply #1 on: October 03, 2012, 08:23:14 AM »
***

Hi Roger.

I doubt that there is a simple answer to your question. Without going into pages, the problems with UV fluorescence as an analytic tool include the following:
  • lamps vary somewhat in the wavelengths that they emit, and consequently the fluorescent effects that they have. Expensive ones for mineralogy costing hundreds of pounds and cheap ones for stamp collectors costing 15 or so do not necessarily act in the same way. A (very) rough analogy is the differences you get with incandescent bulbs, LEDS, or sunlight when taking pictures using visible light.
  • human eyes vary, and colours are subjective. Some people cannot even distinguish red and green, remember. Is 'dusky pink' or 'pale straw' colour something we all recognise and agree on?  I doubt it!
  • the fluorescence from paperweights can vary depending upon impurities in the glass (and in turn the source of the raw materials), and even depend upon how the paperweights were annealed or held in the glory hole.
This is not to say that UV testing has no merits: for example,  it is useful for showing whether there is lead in the glass, as with any UV lamp you will get a blue fluorescence with short wave radiation. And it is useful for helping attribute weights when there is a big enough database of results, and sufficiently great differences in fluorescence, to make tests meaningful (Kev H has shown this with Perthshire, Ysart Bros and so on).  But even with many results there can be problems. I have been told by several people that antique Saint-Louis paperweights fluoresce 'dusky pink'. None of mine do under my UV lamp, at short or long wavelengths. That is not to say that the others are wrong - just that results can vary a lot, and that UV is by no means a magic bullet for solving problems of attribution.

What would help would be a comprehensive study using University laboratory standard equipment for illumination at specific UV wavelengths, and accurate spectrometry of the emitted light. But I doubt anyone has the money for that!

Alan
Alan
The comments in this posting reflect the opinion of the author, Alan Thornton, and not that of the owners, administrators or moderators of this board. Comments are copyright Alan Thornton. Please feel free to contact me direct if you do not agree with my comments and do not wish to make your concerns known by posting in this thread.
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Offline Roger H

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Re: Scotia paperweights
« Reply #2 on: October 08, 2012, 09:57:46 AM »
Thanks Alan, thats a pretty good summary of the probabilities and it makes sense. As I dont have any other scotia weights  I was curious as to other collectors perception of the UV reactions of scotia weights.
   This seems to be a scotia weight but it would  still be interesting to know what composition WM used at the time as I can find no reference anywhere as to UV testing of them.
         Regards Roger.


 

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