Early foxing detection: UVC seems good!

I said before how much I like UV, and I said before it can break your heart also. Here is a nice example of seeing what you don't want to see, via UV.

This is a Cambodia 10000 Riels banknote from 2006, bought as UNC from a guy on eBay.

On first inspection I saw nothing wrong with it at all. These are the scans:

Now the images under UVA (365nm):

And UVC (254nm):

Under UVC the note is absolutely riddled with fine foxing. Some of this is then detectable in retrospect if you go back to the scans. For example there is a dark spot near the 4 of the serial number:

But a lot of these are not obvious even on close-up scans. Yet they are very prominent especially under UVC. Look here at the right hand side of the reverse, this is under UVC. Each one of those black dots is foxing:

Here's another flatbed scan, a bit darker:

Some of the spots can be seen under white light, but not nearly as easily as under UVC. 

Under UVA you can see some of the spots, but it seems UVC is more sensitive. Here's the same part of the note under UVA:

I can't fault the seller. He would either need to check the note under UVC before selling or magnify it and scrutinise it, which is not practical.

Whilst the note is UNC, the foxing spoils it. 

Once I see it, I can't unsee it, and now I think of it as AU.

That's interesting but I just wonder how many banknote vendors would allow buyers to UV scan their inventory before a purchase.  I mean that would (obviously) be when an UV scan would be the most beneficial, right? 

That will never happen. The primary reason being this: it takes a fair amount of setup and equipment to take those pictures. I do it in a darkened room with a camera on a tripod and a UV light that costs £96 today.

So it will be impractical for a buyer to pitch up at a seller's business and check the notes under UV. It might be that the note is so badly foxed that it shows up in ordinary lighting with a cheap UV light, such as that Canada $100 note I won on the Katz auction. 

But this Cambodia note would escape casual physical inspection and casual UV illumination also.

It is really only useful for a seller who checks notes beforehand. This has happened recently, again with Canada notes.

I bought several $20 notes from various sources and they were indeed UNC when examined. I can't fault the sellers. 

But: they were contaminated under UV and I couldn't use the images for Numista. So when I bought the next two $20 notes I made it a condition that the vendor checks the notes under UV because the main driver for me was a clean note under UV, which was also UNC. 

1. One eBay seller said he can't check it because he has no UV light

2. Another eBay seller said he has the UV light and will check it. He then did not get back to me, presumably because it was contaminated

3. TheBanknoteStore (Kate Bouvier's online store) said they had the light and would check the notes. They did that, emailed me clean pictures and I bought two notes, each one £30 which I was happy to pay. And they sent those in individual sleeves because the paper on those older notes is quite rough and can pick up UV ink from adjacent notes 

As soon as I got them here, I scanned them, photographed them and put them in a double sleeve storage. They go into a Storage Boutique soft flexible sleeve and then that sleeve goes into a rigid acid-free PVC sleeve.

That's the best I can do.

Unfortunately, the more lights and examination tools you have, the more chance of discovering blemishes, contaminants and so on. 

I have blacklisted two sellers on Delcampe for sending notes that are contaminated, not UNC and so on. 

I believe (but cannot prove) that if a seller sends you multiple notes from different years and different countries and you find blemishes, foxing and such on those notes…he probably is not careful when storing those or he is sourcing them from someone who isn't careful.

I am also convinced that some papers are susceptible to trapping dust and moisture. The Canada Bird series from 1980s and 1990s is one such example. It is extremely difficult to get dust off those notes. I am still looking for the right tool to do it. Maybe a low-powered vacuum device with a soft bristle stand-off would do it, I am not sure.

It's very disappointing to hear that you have struggled receiving issue-free UNC notes from Canada. I really hope that it improves for you. Good to hear that Kate pulled through on supplying some issue-free CAD but I have to tell you that I got a South Vietnam note sold to me from her as UNC but it had foxing. I have just gotten to the point where I will ‘suck it up’ if my order has the main note I was seeking in UNC. I realize that this is probably not helping the hobby (sucki but I have found it next to impossible to get UNC notes this past year 

It's very disappointing to hear that you have struggled receiving issue-free UNC notes from Canada. I really hope that it improves for you. Good to hear that Kate pulled through on supplying some issue-free CAD but I have to tell you that I got a South Vietnam note sold to me from her as UNC but it had foxing. I have just gotten to the point where I will ‘suck it up’ if my order has the main note I was seeking in UNC. I realize that this is probably not helping the hobby (sucking it up) but I have found it next to impossible to get UNC notes this past year. I have found myself purchasing less & less in the past year. Thanks for sharing & remember if you want A 2nd opinion on a CAD LMK!

That's a shame about your note. Kate will take it back, at least. 

Does the foxing on your note show up better under UV?

I have noticed that a touch of foxing is an issue from time to time on ‘UNC’ modern notes, especially from countries with warm damp climates!

Nicely done on the UV examination.