Originally Posted by
ccdjg
Matt,
The UV test is based on the fact that UV brighteners were first introduced onto the paper and card making industries in 1950. These invisible dyes convert the invisible UV light in daylight into bright blue/white light and so make white card and paper look even whiter and brighter. They were so popular and cheap that by about 1965 virtually all commercial white card and paper had these in. In fact it is now extremely difficult to find any without them in, so much so that paper with no UV brighteners is used for banknotes, knowing that forgers have a very hard time getting such paper.
So if anything with white paper labels or made of white card glows blue-white under UV light, you can be 100% certain that it was not made before 1950.
On the other hand, if it does not glow under UV you cannot be 100% certain it is a genuine pre-1950 product, because the use of UV brighteners was phased in, but you can be very near certain that it is pre-1965.
So the UV test is by no means the perfect dating tool, but it certainly can be a big help, and for the cost of a few pounds off Fleabay it is a no-brainer.
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