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Almost all colour laser printers add a repeating pattern
very small yellow dots to printed page. This pattern,
which is barely visible except under blue light and
magnification, encodes the make, model and serial
number of the printer and, in some cases, the date and
time of printing.
Its purpose is purportedly to enable the
tracing of forged documents.
MaxCo., true to its company motto of "Never Knowingly
Responsible", is therefore proud to announce its range of
pre-dotted printer paper. Each sheet is bespeckled with
superimposed and randomly-offset yellow dot patterns
copied from a wide range of colour laser printers, foiling
any attempts to trace the source of anything printed
Moreovermore besides, we are also about to launch our
range of "Copy-Me-Not" paper, preprinted with the little
constellation of five somewhat larger yellow dots which
appear on banknotes, and which colour photocopiers
stubbornly refuse to copy. Any document printed
thereupon will, when photocopied by a modern copier,
produce only a black page.
The anti-copying mechanism referenced above [ytk, Jul 29 2013]
Yellow tracking dots by laser printers
[MaxwellBuchanan, Jul 29 2013]
The Garden of Cyrus, or The Quincunciall Lozenge, or Network Plantations of the Ancients, naturally, artificially, mystically considered
Thomas Browne, 1658 [pocmloc, Jul 29 2013]
||Bun for the first part, but unfortunately the EURion
constellation, as the anti-copying pattern is known, is
generally only respected by color copiers. The vast
majority of copiers, even modern ones, would be
||I didn't know this. Does it work with black light?
||Can you arrange it so when it hits a predefined prime number of prints function X goes into effect?
||Function X is where one page of the document gets printed with coffee cup rings, lots of crossing out and apparently handwritten annotations in the margin saying what utter tosh the author has written.
||//Does this prevent scan and print as well as copy ?//
||I'm not sure about scanning, but many image editing
programs (like Photoshop) will refuse to operate on
images containing the EURion constellation (or other
anti-counterfeiting watermarks). (link for more info)
||// the anti-copying pattern... is generally only
respected by color copiers// Yes, that's true.
||//Does this prevent scan and print as well as copy
?// Not sure; I would guess that high-end
scanner/copiers apply this to the scan as well as
the print parts.
||//Does it work with black light?// If you mean the
banknote protection - no, because it's designed to
work with normal copiers that don't have a
blacklight. For the yellow-dot-encryption of
regular colour laser printouts, the dots are printed
using the normal yellow toner of the printer; they
might be easier to see under blacklight, but they
can be seen by eye using a blue light and a
magnifying glass; you can also see them if you
take a high-res digital photo and play with the
"yellow" channel on the image. But the naked eye
isn't very good at seeing yellow on white.
||//some other stenographic system// Yes, there
are some anticopying features in addition to the
Eurion pattern. I tried playing with banknotes (UK
mainly) and found that whilst the Eurion cluster is
enough to prevent colour-copying, there are also
some other non-obvious parts of the image that
||But mainly this idea is about thwarting the yellow
microdots that encode all of your colour laser
||//Photoshop and other image programs rely on some
other stenographic system// You mean they have
one of those courtroom typists?
|| //Does this prevent scan and print as well as copy ?//
Medical prescription paper does. I grabbed a sheet from our
veterinary pad and tried it out on our HP scanner/copier
and my mother's Canon does-it-all machine. VOID.
||Interesting. Does it have the Eurion code on it? Or
something else? Presumably you could scan it in
monochrome through three different colour filters,
then combine the three images...
||I dunno from no Eurion code, but whether scanned-and-
printed or simply copied, they always come out with the
word VOID blocked across them and a two-part serial
number along the part where the doctor signs.
||I haven't tried the monochrome idea, but it still voids if you
scan it in color and print it in b&w.
||It's not a specific code, actually. It's a special type of
printing. One common technique involves printing the
word VOID so it is easily visible to both the naked
eye and the copy machine, but the surrounding
background is effectively invisible to the copier (or beneath the threshold for
visibility when converted to monochrome). Since
the word gets reproduced by the copier but the
background doesn't, it stands out. Another method
involves taking advantage of the reduced resolution
of the copier, so that a series of apparently
unconnected dots and lines blur together a bit and
form a word when photocopied. It's not just
prescriptions, either; checks are commonly printed
using this kind of security method.
||Ah, OK - that's different from the Eurion system,
which relies on firmware in the scanner/copier. If
you try to photocopy a banknote in colour, most
copiers will just print a completely black (not blank)
page, even beyond the bounds of the note.
||[Max] - next time you visit your competitor's MSL*,
take something you can copy. Take a yellow-inked
rubber EURion stamp, stamp your original just
you put it on the glass, and it'll probably fail to
But (and here's the bonus) the fresh-stamped ink
transfer to the glass; it's pretty transparent so it'll
very hard to see, but will prevent the copier from
working on anything until it's cleaned off.
||(or just stamp the glass...)
||*Mad Scientist Laboratory
||I'm so disappointed, my computer and scanner and printer had no problems with me making a duplicate of a banknote covered in those little dots. (OK I worked out I bought the scanner in 1995).
||Do you think the dots are patented, If I insert a few discretely into my letterhead will I get sued? I just like the idea of my correspondents having mysterious problems when they try to photocopy my letters to them.
||[poc], can I borrow your printer and about 250 toner
||You can bloody well buy your own toner you blagger. Also my printer does make yellow dots.
||I have not yet tried printing the quincunx pattern from Wikipedia, that is the next experiment. Anyone else have any success printing a yellow eurion shape?
||I tried to duplicate the Eurion, based on images from
the Interweb, and found that it still printed and
scanned on a protected colour copier. There is
some feature of it that is not easy to replicate.
There was (but apparently no longer is) a utility
available to Eurionize PDF documents.
||Pretty much all modern laser printers do.
||Hmm, so the Euro could be replaced with small paper yellow circles...
||Sadly not. The yellow circles are part of the system
that allows scanners/copiers to recognise potential
banknotes and refuse to scan them. Sadly they are
underadequate to cause a banknote scanner to
accept a piece of paper as being a banknote. This is
probably why yellow toner cartridges are not
significantly more expensive than the other colours.
||That's shocking, I mean ,if they aren't prepared to take a chap's word on the value of those yellow circles, what is the world coming to?