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 CD Home < Web Techniques < 2001 < August  

Protect Your Sites

By Clayton Crooks

If you're a Web designer, you've undoubtedly spent countless hours designing and perfecting the various graphical elements of sites on which you work. With all of the time and hard work you put into a site, it's certain that you'd do everything you could to protect the site from easy theft. Copyrighting the site is the obvious first step to take, as a copyright protects unique works ranging from books to Web sites.

However, even if you protect your works with a copyright, they'll continue to be an easy target for unscrupulous individuals who can download some elements, or even all of your site, and call the work their own. If you're serious about protecting your investment, you should know about new technologies like digital watermarking that let you enforce your copyright.

ImageBridge and ImageBridge Pro
Digimarc
www.digimarc.com/imaging
cost: Contact vendor for pricing.
Pros: The best solution available for protecting Web media. Cons: High durability settings can cause visible distortion.

The Basics

When you think of watermarks, you probably envision the traditional type that's applied to paper. These watermarks are mostly transparent and are added to a document to offer proof of authenticity. Digital watermarking uses the same basic idea, but it acts on image files and is accomplished with the use of software like Digimarc ImageBridge.

Digital watermarking is currently the best protection available to Web designers. It lets you invisibly sign works, so you can demonstrate your copyright in disputed claims. A Digimarc watermark is a message, like a copyright notice, that's embedded into an image, navigation bar, button, photo, video, or any other type of visual content. The ImageBridge software embeds the messages by making subtle changes to the brightness of the pixels in an image. Differing from their printed counterparts, digital watermarks are usually imperceptible to a casual viewer.

Tracking Images on the Web

Using digital watermarks can let you prove that an image is owned by you, but how can you possibly track image theft? After all, there are millions of Web sites—too many to be checked manually—to determine whether the images on them are owned by the respective sites. This is where Digimarc MarcSpider comes in handy.

MarcSpider is a service that you can add on to ImageBridge for an extra cost (licensed through a partnership with Cobion). It crawls around the most highly trafficked public areas of the Web looking for images. When it locates an image, MarcSpider attempts to determine whether the image has a Digimarc watermark embedded in it. If so, it records the image location and details such as the date and file size. Users of the service have unlimited access to online reports that contain thumbnails of the images found, along with links to the pages containing them.

Of course, a service like MarcSpider can't possibly cover the entire Internet. Its searches are limited in scope by the major search engines, which, according to NEC Research Institute (www.wwwmetrics.com), account for only 15 percent of the sites on the Web.

Standard or Pro?

To use ImageBridge or ImageBridge Pro watermarking, you must first subscribe to Digimarc (www.digimarc.com). For basic communication of copyright ownership that lets you display contact information, you'll probably need only the standard ImageBridge services. But if you want to use images with transaction ID numbers or if you want to include links to image-specific information on your Web site, you'll need the Pro version.

Once you've determined the version you need and have subscribed to the appropriate service, you'll receive a 2-digit PIN and a 6-digit Digimarc Creator ID with which to watermark your images. Next, you must determine which software package you'll use to embed the watermarks. Some products, like Jasc Paint Shop Pro and Adobe Photoshop, are Digimarc ImageBridge enabled, meaning that you can embed the watermarks directly from these products.

Embedding the Information

Regardless of the software you use, embedding a digital watermark takes only a few simple steps. First, you must run the Digimarc plug-in for your respective software application. For instance, if you use PhotoShop 6, the Digimarc plug-ins "Embed Watermark" and "Read Watermark" are found via the Filters menu under Digimarc. To enter your Digimarc ID, choose Embed Watermark and a window appears that lets you personalize your software with your Digimarc ID and PIN.

Once you've personalized the plug-in, you can use it to embed information such as copyright date and restrictions. The plug-in also lets you determine the visibility at which the information is embedded. The more visible the watermark is, the more durable it is. Likewise, as you lower the visibility, you lower your chances that the image will maintain the watermark if it's modified. The sole advantage to using the lower visibility watermark is that it's less intrusive.

Watermarks in Action

Digimarc's digital watermarking works best with either color or grayscale bitmap images. Vector images can be watermarked only after they're converted to a raster or bitmap format. Watermarks can be used by any file format supported by applications such as TIFF, PICT, JPEG, and BMP, to name a few. And because the watermarks are carried by individual pixels, they're present even when an image has been converted from one format to another.

To adequately protect the long hours you spend developing Web content, you should use a combination of approaches. First, you should take the time to copyright your materials. Once you've done so, you should investigate the digital watermarking technologies available from Digimarc, Signum Technologies, and FotoNation. These technologies currently offer your best defense.


Clayton is a freelance writer and independent consultant based in Knoxville, TN. Reach him at crooks@planetc.com.




Copyright © 2003 CMP Media LLC