Guide to buying a UV torch for banknote forgery and wrinkles/folds detection

Hi all,

I was wanting to purchase a torch (or two) to add to my arsenal of bank note quality checking. There seem to be a couple of different nm wavelength UV torches out there, but am not sure which nanometer wavelengths to purchase. 

Also features like how many LEDs would the torch need to have at a minimum in order to give a good indication of waves/folds/wrinkles etc.

Another aspect of banknote quality checking I would like to discuss is the method of lighting a banknote in order to see waves, fold or wrinkles, however tiny they may be.

I normally ask sellers to send me photos like the one below:

Another method could be to place the banknote flat on a black surface and shine a torch along the side of the note.

Which method do you think is better?

Is it a widely held opinion that yellow light is good for detecting pressed or washed notes? I'm trying to understand the science behind it.

ruler.of.kutch

There seem to be a couple of different nm wavelength UV torches out there, but am not sure which nanometer wavelengths to purchase. 

The most important UV wavelength for looking at and checking banknotes is 365nm. 

Be careful, most UV lamps (or torches as you call them) which can be bought are 395nm. Do not buy them for your specific needs. You need 365-366 nm. This is the standard wave length for ''banknote phosphorescence.''

If you also want to check fluorescence you you need a lamp with 254nm. But fluorescence is rarely used for banknotes.

For example, Lighthouse has table and hand UV lamps available. They do the job.

Also features like how many LEDs would the torch need to have at a minimum in order to give a good indication of waves/folds/wrinkles etc.

State of the art lamps only need 1 LED these days. Older models have 6 or more. So, it's trial and error. 

I would take @redlock advice since there are many cheap/ineffective products out there.

Here's a link to this UV topic started by @Ruibai  from 2022.

Here's a link recommending a UV section on Numista started by @kingofxbox99  also from 2022

Re: side lighting on circulated notes:

Your 1st photo amply demonstrates the value of a well lit note! It is very difficult to get a good photo of a note & I think the 20 Pound note shows how not to do it. The camera (or focus of your shot) must be close enough to reveal the bumps. Scans often hide or obscure imperfections & are mostly useless (except they show UNC notes well). Getting decent photos which reveal a note's imperfections can definitely be a challenge.

I am not really sure how to adequately describe the process of showing/understanding the difference between a pressed VS an “original” (unprocessed) note. The main difference is that a pressed note lacks embossing, the indentations which occur in the production of the banknote (especially seen on the opposite side of the serial numbers) for paper. You should also see wavy paper, cutting cups (where security threads are part of the note) & other 3-D impressions.  A lot of collectors dismiss these minor bits of evidence that a note is original at their peril. Read on & hopefully I can explain why.

Hard (heated) pressed notes (with an iron) are typically duller than their original counterpart. They lack hues/richness of colour. Serial numbers may appear duller or muted.  The note looks faded compared to a non-pressed note.  You also see whitish lines through the design where the creases once were & other “tells.”  It really takes practice & viewing a lot of notes. Look for diminished ink where the colour seals are or where the signature should be (& other areas).

Whenever I see a bit of spurious colour on the note's border, I suspect the note to be washed & start searching for other “tells” of banknote processing (cleaning & pressing).  I usually end up  finding several other suspicious regions b/c an unsavoury individual figured that they've started the job of making a note look better, why not finish it?  That's one of the problems with pressed notes: the fact that they're typically hiding more problems than what is apparent.  Each processed note is literally a Pandora's box.  I honestly view each non EPQ note as a problem note! (Even though some may not be). 

Check this link on CCF where a 1914 $50 note is up for auction. See the comments of 30-40 year veterans immediately after (guessing the note to be EF) & scroll to the end.  This note was also registered on Track & Price as a Fine (& sold for $381.00) but on eBay sold as if it were an EF (2 grades higher for $1225.00) because it was processed (washed & pressed). Did the bidders know?  I'll bet the buyer who forked out $1225 had no idea the note was processed! That's why I say it is so important to learn about grading (especially if you're going to buy more expensive notes) + it is a good skill to acquire b/c even the TPG's can get it wrong (they're human & grading is subjective).

Finally, here's a good link for a general guide to grading banknotes.

Hello,

I confirm that 365nm reveals many more elements than 395nm which gives a too intense rendering.

i too have noticed alot of weak uv lights ive already wasted money on two of them and decided to check here, most of the notes i have are from either Russia, Kazakhstan, Iraq, Iran, North Korea, and i have a complete set from Malawi which is supposed to have some strong uv detection

Check my signature for three articles I wrote, the third one is about UV.

For UVA you need a 365nm UV light

For UVC you need a 254nm UV light

Folds are best seen using a white light from the side, but another way to see them is via infrared, which will be the fourth article I write.

The UV light needs to have good filtration, mine is an expensive unit about £80, a Lumenshooter S model. But well worth it, you can see the images I got with that in the article.