Watermarks & Anti-copy Devices
Georgi Penev
It's pretty much an industry standard but only works in BITMAPS which means
you will have to convert your corel stuff to a gif or jpg or tiff or
something.
George
"F. Startz" wrote:
> Has anyone ever found a successful method of making it difficult to
> photocopy a document printed from CD8? I'll be offset printing a booklet
> for someone and he's interested in coming up with method to prevent anyone
> else from later copying his document.
>
> I've thought of using a grayscale watermark to underlie the printed page.
> However, finding the correct balance between a shade of gray that doesn't
> compete with the readability of the text and drawings, and a shade that's
> dark enough to appear as black (or dark) when run through a photocopy
> machine, is tricky.
>
> I've also heard of using gray text and printing it on light blue paper. I
> tried that myself at home once but the results weren't so good.
>
> Maybe someone has already successfully done this? Any ideas will be
> gratefully *tried* <g>.
>
> Regards,
> Fred
Dale Green
Georgi Penev <to...@trellis.net> wrote in message
news:37B3724B...@trellis.net...
> Go to http://www.digimarc.com/
>
For photocopies??
How about microprinting (like cheque borders)?
It would depend on your output device whether or not you could print it well
but it shouldn't survive photocopying.
Not that I've tried this...
Dale.
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F. Startz
F. Startz
circulated documents. I need an idea to use that would render useless (or
less than good) a photocopy of a *printed* booklet.
The microprinting idea would be just right for security-type documents (like
a cheque [check? <g>], but it wouldn't necessarily thwart someone intent on
copying and then using the text and drawings of a printed document. It would
be conceivable that the filtcher (thief, in plainer language) could copy the
document, cut the micro-printed border off, and then photocopy the document
remains once again. He or she would then have a 3rd generation, clean copy.
I did some more research since my original post. Two methods -- both of
which I've never seen and little understand-- are: First, using special
printing inks that shift color (or shades of gray?) during the photocopying
process. The second method uses luminescent inks (like Day-glo, I guess?).
These inks have wave lengths that a photocopy machine can't read, so the
copy would come up blank. If those ideas work, they sound great. However, I
don't know the availability or the cost of using those printing processes.
Cost would probably be a main concern if these processes are technically
difficult for printers to use.
I'll make some more enquires later today, but anyone's "homegrown" idea
might be just what's needed. Thanks again for the help. I'll post back here,
myself, if I learn anything new later.
Fred
Daniel Schmidling
Try this ... Take the color refrence card that came with the Draw package
(there is also a file (TIF I think ) in the color manager of it). and run it
thru your local Xerox. from this experiment you may find color combinations
that will be readable , but Xerox the same , then you need to get with the
printer to see if this can be duplicated . If I rember corectly light blue
on a yellow / tan background works, but there is no way to make something
"copy proof" as most digital folks know. Then again not too may people have
color copiers , or make the size so it is difficult to process, you ever try
to Xerox a newspaper?
Best Regards
Dan S.
F. Startz
How's it going?. You're last suggestion, first: A newspaper page *is* an
armful to copy <g>. But jacking up the size of this document won't work
because the booklet is designed to be -- what else? -- a 90-page
"shirt-pocket handbook" for field site employees. The size idea is a good
one but in this case all you'd do is further p.o. a bunch of field workers
who already aren't too happy about living in the middle of nowhere for weeks
at a time <g>.
I'm going to experiement with your color card idea for a day, but because of
time constraints, that's all the time that's left. This booklet is ready to
go to press. I should've asked my watermark question earlier, but let is
slide. I know that if you're printing a few copies of a document on a laser
printer you can "almost" come up with a shade of gray for a background
watermark that won't photocopy too well (it'll turn darker). However, I
haven't much experience with watermarks and offset printing (500 copies in
this case). Nonetheless, this anti-copy information will serve for the next
book made.
Thanks and see you later,
Fred
artenall
coloured paper, such as red, photocopy very poorly, yet the black text
stands out quite well on the original print. Worth a try??
Regards
John
Georgi Penev
but you'd better ask them.
There IS an option where you choose how long it will last. Ie. how many
processes or scans or whatever you can run it through.
George
Georgi Penev
Here's one thing I've learned. Since my printer prints better and in more levels
of black/grey. Whenever I've put a watermark in very light grea on the paper and
had it photocopied (or the customer did) it almost ALWAYS shows up MUCH darker,
ie. VERY OBVIOUS on the photocopy. Try that first. 5-15% grey or something.
F. Startz
I just saw your post. Thanks. Yeah, I'd thought of using colored paper.
Somewhere I read light blue paper with gray text won't photocopy at all <g>.
The red with black text sounds good, too. But this is to be a training book
and I worried that if I got too "clever" the book might not be effective.
I'm not being facetious -- trying to read off of red paper in a remote site
camp at night with minimal lighting might be difficult. That's why I ditched
that idea kind of early. If it weren't for the use of this book, I'd have
used a paper/text color combination to thwart copying.
Thanks again,
Fred
RichZ
for. It 'assumes' that the lightest shade visible is white, and the
darkest is black, and adjusts the contrast accordingly. So unless the
paper were so dark as to be pretty tough to read to start with, that
setting (found even on relatively inexpensive copiers) could
circumvent the idea.
RichZ
www.richz.com