In case anyone else encounters this thread and wants to know, that would be our PDF Stamping feature:

37http://www.e-junkie.com/ej/selling-ebooks.htm37

Is there a way to stamp audio files in a similar way?

I am sorry, but we do not have a way to stamp audio files.

Hi, is there a way to add an additional invisible (in white font for instance) watermark somewhere on the page? I think that could be a nice security feature.

We try to walk a balance between visible and unobtrusive with our current PDF stamping. The mark has to be visible so that the buyer knows it is there and is discouraged from sharing the document while not being prevented from using or enjoying the document by the mark itself. An invisible mark would certainly be unobtrusive but it wouldn't do anything to discourage file sharing. You could still add in such text or marks as part of the original file, though.

hi there, sorry if i'm reviving an old thread here, but if the watermark is easily visible, how is this
going to discourage any sharing? a person can simply make screenshots of the pages
and just remove the watermark.

I'm personally not a writer, but a visual artist selling hand drawn and 3d rendered pictures.
So a book with several hundred pages might be a lot to screenshot and edit, but with a bunch
of pictures will be too easy to edit.
Is there a chance of the E-Junkie team addressing this issue?
Thanks

Nobody can prevent sharing/copying of files downloaded over the Web, as computers inherently allow users to share/copy any file on them, even if they only download it once.

It's only possible to put obstacles in their way, such that they either don't know how to get around them or would probably deem it not worth the effort, so this really just helps keep honest buyers honest to deter casual file sharing.

Our PDF Stamping feature can deter most sharing of PDF files, as users are generally unwilling to share a file that contains their personal information and can be personally traced back to them.

Certainly this is not invincible; the method you describe could be one workaround, but it's so labor-intensive that realistically speaking, few if any buyers would bother investing their time and effort in such a painstaking task.

Of course, you still own the copyright on your own content, so if you find a copy circulating in the wild anywhere, you can send a formal DMCA takedown notice to the host demanding they remove the infringing content.

Indeed it is impossible to completely prevent files from being shared online, I understand that,
but you must admit that the current system isn't optimal and just too easily circumvented,
at least when it comes to pictures.
I've seen products from other artists who have a hard-to-see watermark, so it definitely is doable.
And while I'm not a programmer, I can imagine it's not that hard to code something like that.

I really like E-Junkie's layout so far and have been using the online shop for a couple of years now.
I'm sure a lot of artists out there would appreciate an alternative watermarking system that
pastes a 95% transparent font with any info tracable to the buyer on each PNG or JPG file

also, DMCA takedown requests are usually being ignored by those illegal sites

thanks for the quick response btw!