Bank note testing

[Loosehead]

Just been to my local ASDA. I paid with �20 note and they used some sort of pen on it to verify it was real. Anyone know how this process works? I mean what stops forgers duplicating the process? Presumably it's very difficult to forge whatever it is that gives the "right" response to the pen.

[xrayspecs]

The pen will not be visible on true bank note paper. If the pen marks the paper the bank note is a forgery.

[Loosehead]

I know that xray!

But why can't the crooks just make notes with the right chemical on them? Why does it stop forgery?

[noxlumos]

There was a fascinating scam some years ago I heard about whereby someone would visit smaller shop premises pretending to be a rep selling "counterfit detector pens". They would demonstrate the effectiveness of the pen with a real one and when the shop keepr bought one would provide them with one containing only water, thus the criminals knew which reatail outlets were safe to get rid of their counterfit notes in.Ingenious but simple.

[Buenchico]

Loosehead seems to be assuming that the pen reacts with a chemical which is added to the paper. This might be true but I've always assumed that the chemical in the pen reacts with the actual paper itself. (i.e. if it's used on a wood-based paper it shows grey or brown. If it's used on the cotton-based paper which is used for banknotes, then it shows yellow or clear).

Chris

[gen2]

My understanding is that the pen contains a weak solution of iodine. Most papers available to ordinary people contain starch. Iodine and starch react to give a dark coloured complex which the shopkeeper sees as a prominent mark.

The paper used for genuine banknotes contains no starch and the pen colour will not change. Once used the iodine evaporates and the banknote appears clean again.

Yes forgers gan get round it - if they can get hold of genuine banknote paper.

Of course, there are many more anti-forgery features designed into banknotes. No one should rely on the pen alone to detect fakes.

[Loosehead]

I wasn't assuming anything Buenchico I didn't know.

gen2 seems plausible I just wonder though if a forger is going to the trouble anyway they would steel the right paper too.

[Gevs1966]

loosehead, gen2 is mostly correct. However, there are many factors which make these pens extremely unreliable as counterfeit detection. One example would be if a banknote had ever been through a washing machine or been loose in the pocket of a starched shirt for a while. Most places that use these pens and the small uv lights that you see around don't actually know what they are looking for anyway.

There are many security features incorporated into banknotes around the world, there are many different types and in this country not very many are actually incorporated into our notes as there is no counterfeit problem here. There are covert features which the general public and retailers will not know about and overt or public recognition features which are obvious and include the watermark, the thread and holograms.

Also the chance of any criminals stealing real banknote paper is quite laughable in this country

[xrayspecs]

You've obviously never been given a snide �20 note then Gevs. Counterfeiting IS a problem in this country, which is why companies like delarue (bank note printers) operate such tight security. It's actually very simple to duplicate the type of paper that bank notes are printed on, what is more difficult is to replicate the water marks and silver banding that are added into the weave.

[xrayspecs]

Also - What use is a "Covert" counterfeit measure?? Are you sure you haven't crossed over into some James Bond Fantasy!

[Gevs1966]

xrayspecs, it's ironic that you mention delarue. They are my current employers!

Th uk banknotes are probably only about 5/10 in terms of security as there isn't a particularly big counterfeit problem in this country. The reason for this is that circulated currency returns to the bank very quickly due to retailers banking takings on a very regular basis. Contrast this with African or Middle Eastern countries where the majority of the trading still occurs in markets and villages with no real banking network, the notes in these countries do not return to the banks for some time massively increasing the opportunity for effective distribution of counterfeits!

[Gevs1966]

and another thing, one point of covert banknote features is that those who are inclined to counterfeit don't know they are there, but the Central Banks of the respective countries do so they can easily be identified.

[alphamale]

If it was a UV light pen then they are looking for the watermark or some other UV property. Just because it is pen shaped does not mean it's a writing pen. You can get single LED UV pens.

[Loosehead]

Who said anything about a writing pen? I used the word pen to describe a pen shaped tool. It was more akin to a highlighter pen!

[boobesque]

where i used to work we did tests on different types of paper to see the effectiveness of these pens. till reciept paper (thermal) and some letter envelopes turned out to be genuine money in disguise. spreading clear nail varnish onto any paper also gives the same effect. for the uv light detectors, the ones that an average shop can afford are pretty crap. if you dont position the note perfectly then it will give random results. of all the fake money i have recieved, manual checks have been sufficient to spot the fakes. the problem is that when a company issues uv lights or pens they dont bother teaching the staff how to spot a fake as they are under the impression that they work.