Preventing Easy Copier Duplication

Mrs Blather is going to sell some knitting patterns. One problem is that people will copy patterns and give them to their friends. Some vendors try and get around this by printing on colored paper but that makes patterns hard to read and difficult to print pictures on.

Anyone know about printing faint patterns on paper to make it work like copy-proof paper? In this day of color copiers is it even worth the bother?

I can give you about half an answer–there is a color of blue that many copiers cannot reproduce. You can (or at least used to be able to) get pencils this color for making editor marks that wouldn’t show up in a photocopy.

Not sure how true this is in today’s copier technology. Also not sure how good this would be for making a pattern, it’s a lighter shade of blue.

The blue you’re thinking of is called “non-repro” blue. Markings in it need to be done lightly, or more sensitive copiers / phot process can pick it up.

How about using red paper? Most copiers will see that as black.

What about putting some kind of watermark or even big bold lettering? (Just throwing ideas out)

Probably not.

Many years ago, I had the original SimCity game for PC. It came with a code sheet, which was black printing on red paper. Supposedly this would prevent me from copying it. But the helpful guy at Kinko’s was able to duplicate it with a color copier, and he even turned the background white so it was more readable.

Today, I’m sure it’s even easier, and color copiers are more prevalent. Anyone with a scanner and a printer will be able to make a copy.

OTOH, color copiers aren’t perfect. With enough effort (and maybe a special type of paper), you can make fine patterns that a copier will reproduce incorrectly, so you’ll at least be able to distinguish between an original and a copy. The new $20 bill is a good example - if you copy it (at your own legal risk), you can still read the text from the original bill, but you sure won’t mistake your copy for the original.

Most copy machines cannot copy from an original printed on red paper; its value is too dark. You could also try using a medium grey for the background, since even the new digital models I work with suck at reading different values of grey on the same sheet - they either want to render the lightest one as white, making the text printed over it too faint to read, or they want to render the darkest one black, making the background so dark it’s hard to read the text.

Color copiers will still read it but few people are willing to spend that much money (every place i’ve worked has charged about $1 for color copies vs less than a dime for b/w).

Lab Test Report just in.

First, none of those rules about non-repro blue or printing on red paper apply to modern color copiers. They see AND print all colors - almost. racinchikki was closest mentioning the gray colors. They are the hardest for a color copier to read.

So this is what I did. I made a small grid of 1 point lines and assigned them different gray colors. Specifically, they were colored as: Pantone Warm Grays 1, 2, 3 and 4 and Pantone Cool Grays 1, 2, 3 and 4. I’m printing on a Canon 1140 one of the best color units in the industry. I printed the grid from my Mac. All of the lines were quite clear on the original sheet, and I would have no trouble working with a pattern from any of them them. I then re-copied the grid directly from the copier. Both Warm and Cool Grays 1 and 2 virtually disappeared from the copy, while 3 and up reproduced fine.

I hope that helps. :slight_smile:

Under_Duck, did you happen to try the same source with a photo-quality scanner and try reprinting?

Personally, I’m against security measures that make it more difficult for paying customers to use your product, but hey…


The Canon I’m using is a photo quality scanner. It’s a very high-end color copier. We do motion picture advertising here, and color proofing is everything to us.

If $1 a page is cheaper than buying originals from Mrs. Blather, or if the knitting pattern bootleggers have color copiers at work, then cost won’t be an issue. (The place where I work has some kind of free ink deal with the copier company, so the only per-copy cost is paper.)

Wow, thanks a lot. I’ll try playing with the grays.

I was referring mostly to black-and-white copiers, since that is what most people have quick access to. Also, Xerox DocuColor 12 color copiers HATE HATE HATE different shades of grey AND blue. Will NOT reproduce them properly and accurately. I spent several hours trying to rectify that the other day and failed miserably. (Had a photo of a white sailboat and a pale blue sky, and could not get the sky to be the same shade of blue in the copy as it was in the photograph without messing up the way the sails were shaded; customer was highly displeased.)

I vote for very pale blue gridlines with a light grey pattern. Readable to the naked eye and anybody who spends enough time and effort to make it nicely readable as a copy worked hard enough to deserve it.

You guys are great, I really appreciate it. One more question: is there a direct way to map Pantone colors to the RGB (or HSL?) scheme used in Word and PowerPoint? I need to do that not just for the copy protection, but also to match a logo whose colors were specified in Pantone.

Before you spend to much time there’s one other thing (IMHO) you should worry about. What if someone just traces over the pattern with black (or other color) pen and then copies it.

Without some kind of hi-tech watermark, modern technology has made faithful reproduction nearly impossible to avoid.

With a $200 scanner (relatively high-end, these days) our dye-sub printer at work, and a little tweaking Photoshop, I can make reproductions of highly color-variant photographs and diagrams that I can barely distinguish from the original, if I use the right kind of paper to print on. Many of these same tools, if they are out of reach for the home consumer, can be used for a small fee at a kinkos or similar print shop. Heck I once took a $1 bill, copied it onto a high-grade paper I bought at a specialty paper store, soaked it in water, and when it dried, it looked and felt enough like a real bill, I’m sure I could have passed it off in a supermarket without the cashier thinking twice.

Of course, I burned the reproduction, ground what was left into a talc-like powder, and scattered the ashes in Boston Harbor, in case any Secret Service agents are reading.

I’m just trying to stop the casual person who will plunk the pattern in a copier to save a few bucks. I know that a determined person can get around any scheme.

How big are the patterns? Can you print them on large paper (A2 or larger) so they don’t fit on most copiers? Color printers are pretty common these days, but A2 copiers are still hard to find.

It wasn’t very true even in yesterday’s copier technology.

I remember working at places that had a supply of clear yellow plastic sheets hanging right by the copier, for use in copying these non-repro-blue documents. The yellow makes the blue ink look black to the copier, and it copies just fine. (We had them because we always made copies of claims we sent in, and insurance & credit companies liked to use that color ink on things like the “your rights” section or the instructions for making claims printed on the back sides of their forms.)

I think you’d better just sell them on the honor system.

These are knitting patterns, not bomb-making recipes. The type of people who would buy them are probably fairly honest types. They might resent your copy-protection schemes as some kind of implication that they can’t be trusted. Just include a friendly disclaimer with each purchase.

You’ll catch more flies with honey…

You know they could just loan them to their friends when they arn’t using them, right? Maybe you could use disappearing ink.

There is no way to make money off of every single person that sees these patterns. Things like knitting patterns will always be shared among friends. Unless Mrs. Blather is distributing on a large scale and facing organized profit-seeking pirates, it’s not going to be enough of a problem to pay back the time investment.