Magic Money Marker

What’s that marker-type pen thing stores use on paper money to see if it’s counterfeit?

What is it detecting? Is it more reliable than the old hold-it-up-and-look-for-the-blue-and-red-fibers dealo?

Probably nothing more sophisticated than your ability to stand still during intense scrutiny.
It tested for that.

(put the commas where you want in the above sentence)

Citizens of the world, please note that we’re only talking about US currency here. I know little about the money elsewhere.

The currency marker contains a solution of iodine. If it turns black, that means the paper contains starch, and therefore is not real currency paper. While this might catch some amateurs using regular typing stock, “pro” counterfeiters use other paper that can pass this test. (No, I will not tell you what kind of paper.)

The colored fibers are also no longer a reliable test, since some hi-res color copiers can reproduce their appearance on white paper. In fact, one model of Xerox copier was so accurate at producing counterfeit money, that the Secret Service asked the company to recall it. The replacement model contains circuitry that senses when you try to copy money, and prints a black rectangle instead. (No, I will not tell you what model, or how the sensor works.)

Technical advances in image reproduction are what spurred the US Treasury Department to redesign our paper money. Even if resolution continues to improve, a photocopy of the new $20 bill will never contain its watermark, the raised printing, or the iridescent ink. Which is, of course, the point.

James Randi said the following in discussing a variety of bogus counterfeit-detectors (Skeptic magazine, Vol. 6, #2, pp. 6-8):

"But the hands-down winner here is the felt-tip pen. This one is patented, which indicates to me that the U.S. Patent Office needs a flushing out to eliminate the dummy who granted a patent to such a bit of nonsense. Let me explain. Many of us will recall, from chemistry class, that a solution of iodine (whether in alcohol, aqueous potassium iodide, or other solute) will turn dark blue and even black when a starch suspension is added to it. The wondrous ‘Smart Money Counterfeit Detector Pen’ is manufactured and sold by ‘Dri-Mark’ company, and the patent number is 5,063,163.

It is simply a regular felt-tip marker that delivers a weak solution of iodine. The theory here is that counterfeiters–again–use cheap paper that has starch sizing in its surface. But the patent papers clearly state that if a bill that has been stroked with a pen shows a black mark, that bill is counterfeit. If the bill shows the expected brownish-yellow marking, it is ‘genuine currency.’

Nonsense. Stroke a piece of newsprint with iodine. The mark stays brown. Does that mean you can spend that piece of newspaper? Stroke some genuine currency, and if it shows a black mark, that can be due to the bill having passed through a laundry machine, or having picked up starch from clothing."

“The response I got from the U.S. Secret Service concerning the silly pen, was that it was ‘of limited use.’ Yeah, like about
zero. The Secret Service does not know of one issue of counterfeit money that would be detected by the ‘Smart Money Counterfeit Detector Pen.’ The very few fakes that are printed up on copying machines by juveniles every year constitute a very small and inconsequential fraction of the total product, and just might be prepared with cheap paper and thus show a black mark. … None of the systems I’ve described here would or could detect the sophisticated product, some of which probably passes through your hands from time to time, unchallenged.” [Emphasis in original.]

“We must fight any attempt on the part of the fringers and irrationalists to call to their side the force of the state. … That we must fight to the death.”
– Isaac Asimov

Just in case anybody was wondering, Randi also addressed those UV lights that some claim can detect counterfeits as well:

“The purple light is simply a 4-watt ultra-violet light that would cost about $20 if purchased through any science shop, but goes for more than $250 if when it has been labeled with such names as ‘Detectit’ or ‘Spectralite’ by vendors of fakery. The claim is that a counterfeit bill will show a bright blue-white glow under one of these lights, and the theory behind such a notion is that counterfeiters use cheap re-cycled paper, that has ‘brighteners’ added to make it whiter. These chemicals (know as ‘kumarins’) do, indeed, glow blue-white under ultraviolet light. I cannot imagine any counterfeiter who would use cheap paper; that business has the highest product-to-material value ratio that I can imagine.”

Whoa! Good catch, David B! (Thanks a lot, I just ordered two gross of the damned things!)

All I know is, when I worked at a theme park, I swiped every bill $20 or larger because I would have been fired if I had been caught failing to do so.

Remember, I’m pulling for you; we’re all in this together.
—Red Green


Nickrz said:

:slight_smile: I actually didn’t put as much work into it (this time) as it seems. The same topic came up on back in January, and I typed it in then. So when I saw it come up here, I headed over to Deja and found my old message.

See, recycling is a good thing!

“We must fight any attempt on the part of the fringers and irrationalists to call to their side the force of the state. … That we must fight to the death.”
– Isaac Asimov