Digital Infrared Photography and Banknotes

Last year I bought a new camera. A Sony Cybershot. This thread is not to promote the camera but to show one of the features that can be used as an additional tool in examining banknotes and to discover details not visible to the human eye.

The camera has a "Nightshot" feature which allows photography in total darkness by using infrared.

I just considered this a novelty until a couple of days ago when I used infrared to examine an "error" on a banknote I had posted. The thread ( http://www.cointalk.com/t127341/ ) was about a Canadian $10 note that had a smearing of what I thought was the ink from the printing process. I had examined the note with a high power loupe and took close-up photographs of it and was convinced that this was legit. However, Krispy questioned it as did a member on a paper money forum.

I had read about using infrared to validate/invalidate banknotes that were thought to be counterfeit or tampered with and thought I might give it a try on the note that I had. The result was amazing. There was no question that the smear on the note was not printing ink but something that was added later (maybe pen ink or maybe tar... who knows?) .





This got me thinking about what else might be visible using infrared. I photographed a couple of notes that I had and here is what I've found:

Canadian notes use two different inks when applying the serial numbers. Evident in this pic:





I only had one U.S. bill handy but I did find something interesting on the back of the note.

First the pics on the note done with normal photography:





The note taken with the infrared setting:




In the next pic notice the blank strip on the left side of the note. Does anyone know if this is a security feature or an anomaly? I can't photograph any other U.S. notes because they are all in my safety deposit box. But I will shoot them in a few days to see if this strip is on all the notes.





I have several notes from foreign countries that I know have features only visible with infrared. I'll post those in the near future.

 

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That is awesome. I'm pretty sure there is a plastic security strip, which is the line on the back. Then again paper is not my thing.

 

Yes! I was so waiting for this thread!

Thanks for assembling all these images and experiments with the night vision mode.

Check out the newmoney.org web site for educational materials on the newer US notes security features. There are tons of PDFs to download as well as some videos and interactive online features explaining them.

I don't know what's going on with that $20 back. Maybe NUMBERS, lettow or RickieB will come along with some ideas. Maybe your night vision images will lead to a new 'article' for SEG later on after some more experiments.

 

Thanks for the link, Krispy! This will help teaching the staff at work, especially during the summers when the U.S. tourists flock up here. We accept U.S. currency in my business and this information will be beneficial.

 

Oh that's great to hear. Glad to help. The BEP has loads of good info they provide free of charge to help. Some are poster sized that you could print and post for employees.

 

@Garrett:

That was my thought as well. From what I've read, the strip was supposed to be visible under UV light in a different color for each denomination. This strip doesn't show up under UV light. It still could be a security feature but not the one I've read about.

 

On wikipedia, they make a comment (w/photo) that the $5 note has two blank strips visible under infrared light. So, this would be a common feature of the newer notes.

http://en.wikipedia.org/wiki/United_States_five-dollar_bill

 

As a home inspector and energy auditor I use an infrared camera. (Don't even ask how much my infrared camera cost. It was almost as much as my car!)

An infrared camera gives you a visual representation of the temperature of the object it is pointed at. Warmer areas show up as a different color than cooler areas.

I don't think your camera is a true infrared camera. I suspect the "infrared" feature works in a spectrum slightly outside the visual spectrum but I doubt it goes into the infrared spectrum. You could do a simple experiment to see if your camera can detect differences in temperature. Place your hand on a table or a wall for 30 seconds (so your hand heats up that area) and take a photo of that spot. If you can see an image of your hand your camera may delve slightly into the infrared spectrum but if you cannot see an image of your hand then it stops somewhere short of the infrared spectrum.

Attached are two photos of a can light - one is a normal digital photo and the other is an infrared photo. I was running a blower door (which blows air out of the house and sucks air into the house at leakage locations) when I took the photos. Note the hot air from the attic being drawn into the house around the can light.

 

These are two different technologies. The one you are using is thermal imaging which reads temperature in the infrared spectrum. The one in my camera is image enhancement which allows viewing in total darkness. It is similar to the nightvision developed by the military. The camera has a bulb which illuminates but isn't visible to the naked eye. The camera, when set in the nightshot mode, removes the infrared blocking filter and the result is the typical green photo that is so commonly seen in nightvision photography.

 

Thanks!

 

Whole Hog

NEAR ir is the way to go. But you need to keep the camera bathed in liquid nitrogen.

Could be inconvenient.

 

ikandiggit, i read the thread that prompted this thread, but do not notice any difference in the 2 expeiramental images. I see just as much of the 'ink stamp' in the first as i do in the second, although it may be slightly easier in the second.

Am i missing something?

 

In hand the "smear" appears to be the same as the ink used in the printing of the "ISSUE OF 2005 / EMISSION DE 2005". I couldn't remove it with a damp towel. When I photographed it using the infrared, it was easy to see that the "smear" wasn't part of the printing process because it is darker than the inks used on the note and it sits on top of the images.

 

Makes me wish I still had my point and shoot I gave to my ma... I might have to pick up a new one

 

Like I need another hobby!

 

I put together a side-by-side comparison of the note under regular light and night vision mode as seen in the image below. What the night vision mode helped me see was more of the surface view of the questionable ink smear or gunk on the note and also that it had a general 'shape', that being more or less rectangular. Additionally, there are at least two distinct shapes that can be detected. Nonetheless, I still feel this occurred after printing and while the note was in circulation.

The red area represents the strongest impression and has the more or less rectangular shape that runs off the margin of the note. The yellow area represents what I would guess to be the second impression from the thing that came in contact with the note. The yellow shape is a little less defined, perhaps due to being the second and weaker impression or one in which most of the gunk transferred upon the first contact. I suspect that whatever the object was that came into contact with the note, may have been wet with something that acted as a chemical agent (even orange juice would likely be strong enough, but not plain water) to have loosened the ink at the moment of contact and caused the ink to smear. If ink smear is not the case (and I don't feel that it is) then the object simply had some tar-like gunk on it which transferred to the note. Just some thoughts/observations that I had and wanted to share after looking this over again.

 

Very interesting, Krispy!

I was tempted to take the camera to work today just to scan the notes that we had from yesterday's deposit but I had too much work to do. I hate it when work interferes with my hobby! I'll have a few hours on Monday because we're closed half day for the holiday. Better when I don't have to explain to co-workers what I'm doing.

 

LOL! The employees will start thinking you are paranoid if you scanning notes all the time.

If you don't have something to similar to this, maybe you should get one... you know, for the hobby.

Counterfeit Detector SLD-16 Demo [YouTube video link]

 

Had one at work....someone stole it the first week. Now I have a UV light pen that I use that I keep on me all the time.

 

OMG! That is crazy! A stolen counterfeit detector! Maybe they thought they needed the lamp for their rave party or something. LOL!