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What constitutes proof, with specific reference to Australia

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My French IS bad  :oops:

And I forgot

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Hi folks,

I felt I really should say something about "scientific proof" - which in fact usually turns out to be no real proof at all, but may be useful in some circumstances.

Ultravoilet and Specific Gravity testing.

Most of us know about the claims of proof of glassware containing uranium, "because it glows green under blacklight". And many of us are also aware that a green UV reaction does not necessarily indicate uranium content (it seems that most soda glass, and aslo lots of lead glass, will show as green under longwave UV light [blacklight]). This highlights a very relevant difficulty with regard to UV testing.

But UV tests can be helpful in cases where enough items from a supposedly known company are checked out. Where testing of many pieces shows one or more definite ranges of UV reaction, any similar item that does not conform can be marked as "possibly not from the supposed maker". It will then require further evidence to establish whether the item is indeed from a different company or is actually the first seen of a new range of UV results from the primary company. The differing UV results indicate a change in the main glass batch, which can easily be the case within any company, particulalry a long-established one.

In my specialist field of Ysart (and other Scottish) paperweights, working on the back of original investigations of other PCC members, I have established that there are, indeed, distinct UV results for various items. These have helped to show that certain items are not Ysart (one specific is that fake py weights show a UV result that is not seen for any period of the genuine item).

So, perhaps if enough pieces from any company are examined under UV, a set of results can be drawn up that act as a guide to "genuineness"?

But UV testing has several drawbacks. Not least of which is the fact that using just a blacklight is not really adequate. Shortwave UV will often show a different result for the same item and it is this dual testing that sets the guide criteria.

Another drawback is that different folk can see colours in different shades (and I am told that generally, the colour sensitivity of men and women is different). This means that a UV reaction in, say, a shade of green, may be described differently by the various observers, with perhaps some claiming a "match" to a guide colour and others saying it's not so!

As for Specific Gravity tests, these can help to identify different glass mixes - for example, a basic soda mix may have a SG value of say 2.4 whereas a lead mix could be at least 2.6. But as with UV tests, SG measures are not definitive and are subject to personal testing variations as well as "technical complications".

I have, however, been able to verify that even though my own SG results differ somewhat from similar tests by others, the results can consistently show items that stand out as "questionable". Again, the fake Ysart paperweights are a good example, where the SG measures are clearly not of the same normal range as the genuine items.

The main caveat with SG tests is pretty much the same as for UV checks - it is not possible to identify a specific company or maker as the producer of a given piece. Only by testing many pieces can a general rule of thumb be drawn up and used as a guide for identifying "oddities".

Both UV and SG tests can therefore be helpful as an additional clue in the excitement (or tedium?) of research.

I have no idea whether these tests would be helpful in checking out the Aussie bits and pieces. But it could be worth a try.


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