When I used to make news graphics for a tv station, every now and then this problem in Photoshop would arise and it was incredibly annoying to make anything with a flat dollar bill as part of the background.
How printers and Photoshop detect and refuse to process images of currency
21–30 of 122 posts
Re: How printers and Photoshop detect and refuse to process images of currency
#22When I was in college (99-2000ish, maybe?), one of my roommates was an art major with a graphic design bent, and he had this high end printer and would copy and print $1 bills and take 20 at a time over to the vending machines around the corner from our apartments once a week or so. After about a month of doing this, the machines disappeared. Of course, he's the same roommate who later got arrested for wire fraud and…
Similar. A friend of mine used an epson stylus printer (new on the market then) and a scanner to copy £20 notes. They were inserted into the change machine in the local gambling arcade type place. It was stupid enough to accept a single sided copy.
Out popped pound coins.
He now works for GCHQ which is funny.
Edit: just to add that these change machines were really naff and obviously built by the lowest bidder.
Re: How printers and Photoshop detect and refuse to process images of currency
#23Re: How printers and Photoshop detect and refuse to process images of currency
#24Earlier quoted context omitted.
"The primary method vending machines use to recognize the denomination of paper money is through a magnetic scan; paper currency is printed with magnetic ink, similar to the ink on the MICR line of a check, that makes it easily identifiable to machines with magnetic scanners. In addition, each denomination is marked with different fluorescent properties. Many vending machines and other machines that read paper curren…
Presumably they were simpler-minded fifteen years ago; either that, or the art major's high-end printer was a lot higher-end than it seemed.
Actually the cheap ones were really naff and relied on correctly sized notes and a mask and backlight with a couple of phototransistors.
A pretty picture cut to the right size would work. I think it was enough to prevent casual errors rather than strict validation.
Re: How printers and Photoshop detect and refuse to process images of currency
#25When I was in college (99-2000ish, maybe?), one of my roommates was an art major with a graphic design bent, and he had this high end printer and would copy and print $1 bills and take 20 at a time over to the vending machines around the corner from our apartments once a week or so. After about a month of doing this, the machines disappeared. Of course, he's the same roommate who later got arrested for wire fraud and…
>he had this high end printer and would copy and print $1 bills and take 20 at a time over to the vending machines
I'm embarassed to admit that in middle school my friend and I did something similar as his dad ran a printing business out of his garage. It surprised us then that this worked so easily. Luckily we only used them on vending machines and we quit doing it before we got caught. It makes me wonder what more sophisticated criminals can get away with.
Re: How printers and Photoshop detect and refuse to process images of currency
#26Earlier quoted context omitted.
Given the cost of high quality ink and paper, one wonders how much less than $1 those bills cost to make.
Given that it was a decade and a half ago, and that even today's vending machine recognizers probably don't do much beyond making sure a few relatively gross features are present, I doubt the cost per counterfeit was all that close to $1.
You are absolutely, positively wrong on this front. The new bill detectors use PCA and SVM to analyze notes. They're so good the treasury department buys them because they're better than the best systems out there.
Generally, however, the vending business is quite cheap. They buy the low end machine because there's not really a reason to bother buying the more expensive ones. However, go to a casino, or a foreign country that uses large bills, and you'll find the story is totally different. The machines are incredibly good.
* Source: I worked in this industry for years.
Re: How printers and Photoshop detect and refuse to process images of currency
#27Earlier quoted context omitted.
Given that it was a decade and a half ago, and that even today's vending machine recognizers probably don't do much beyond making sure a few relatively gross features are present, I doubt the cost per counterfeit was all that close to $1.
"The primary method vending machines use to recognize the denomination of paper money is through a magnetic scan; paper currency is printed with magnetic ink, similar to the ink on the MICR line of a check, that makes it easily identifiable to machines with magnetic scanners. In addition, each denomination is marked with different fluorescent properties. Many vending machines and other machines that read paper curren…
Incorrect. The magnetic detectors haven't been manufactured or sold since the early 80s.
The simplest machines do use 2 narrow optical detectors, but as their algorithms are considered good enough that you have to basically destroy a bill to use them, what's the point.
See my other post about SVM/PCA in this thread.
Re: How printers and Photoshop detect and refuse to process images of currency
#28Earlier quoted context omitted.
Presumably they were simpler-minded fifteen years ago; either that, or the art major's high-end printer was a lot higher-end than it seemed.
Actually the cheap ones were really naff and relied on correctly sized notes and a mask and backlight with a couple of phototransistors. A pretty picture cut to the right size would work. I think it was enough to prevent casual errors rather than strict validation.
These are Japanese machines. The US and Swiss makers are optical.
There's been consolidation in the industry, so there's really only the US and JAP makers left, and the US maker (MEI) is so far ahead of the rest of the world, there's no point.
Re: How printers and Photoshop detect and refuse to process images of currency
#29This is one of the things that made me really see the value of free software. I did verify experimentally that the Eurion constellation alone doesn't trigger photoshop's image rejection algorithm. I think it would be fun to distribute a bunch of images that false-positive the digimarc algorithms, just to mess with people.
That sounds like a decent addition to watermarking. It'd be difficult to crop out a watermark if you can't open the image in an image editor.
There's actually a nice service to build here: "invisible watermarking" for photographers and designers...
Re: How printers and Photoshop detect and refuse to process images of currency
#30So much details on a note makes me wonder, if a message could be steganographed within notes. Something like: If you can see this: Call 1-800-FED
Fun fact: The treasury department won't tell you what is actually on the bills. In fact, none of the governments will. You can analyze them till you're blue in the face, under whatever light or circumstances you want, but the treasury department won't tell you what security measures are on the bill, nor when they change them. Additionally, they sometimes change during print runs, and issues.