Digital Watermarking

To date I have used Digimarc, but are there any other ways of imbedding an invisible digital watermark so that it can be viewed by publishers or tracked across the web?

If you look at Russell Brown's photoshop site, it will show you a very neat way to mark your images, with what ever you like to write........

Thanks Stewart, an interesting website.

Unfortunately these watermarks are visible, if you look at www.digimarc.com you will see what I use and I was looking for something that had no ongoing annual fee associated with it that does the same.

Hi Tom,

You might look at some of the steganography programs (Outguess or JPHIDE?) - they're intended to hide text in images but could be used as invisible copyright markers. I doubt they can be tracked though...

Clive