Digimarc Barcode, based on patented digital watermarking technology, applies a unique digital identifier to Photoshop image files to communicate image copyright protection.

Before adding a Digimarc Barcode

Keep in mind the following considerations before adding Digimarc Barcode to your image.

The image must contain some degree of variation or randomness in color to apply Digimarc Barcode effectively and imperceptibly. The image cannot consist mostly or entirely of a single flat color.

The Digimarc technology requires a minimum number of pixels to work. Digimarc recommends the following minimum pixel dimensions for the image to be protected by Digimarc Barcode:

• 100 pixels by 100 pixels, if you don’t expect the image to be modified or compressed prior to its actual use.

• 256 pixels by 256 pixels, if you expect the image to be cropped, rotated, compressed, or otherwise modified after applying Digimarc Barcode.

• 750 pixels by 750 pixels, if you expect the image to appear ultimately in printed form at 300 dpi or greater.

  There is no upper limit on pixel dimensions for watermarking.

In general, Digimarc Barcode will survive lossy compression methods, such as JPEG, though it is advisable to favor image quality over file size (a JPEG compression setting of 4 or higher works best). In addition, the higher the Watermark Durability setting you choose when adding Digimarc Barcode, the better the chances that the digital signal will survive compression.

Applying Digimarc Barcode should be one of the very last tasks you perform on an image, except for file compression. Use the following recommended workflow:

• Make all necessary modifications to your image until you are satisfied with its final appearance (this includes resizing and color correction).

• Apply Digimarc Barcode.

• If needed, compress the image by saving it in JPEG or GIF format.

• If the image is intended for printed output, perform the color separation.

• Detect Digimarc Barcode and use the signal strength meter to verify that the image contains a signal of sufficient strength for your purposes.

• Publish the Digimarc-protected digital image.

Apply Digimarc Barcode

To apply Digimarc Barcode, you must first register with Digimarc Corporation to get a unique Digimarc ID. You can then include the Digimarc ID in your images, along with information such as the copyright year or a restricted-use identifier.

Using the Watermark Durability setting

The default Watermark Durability setting is designed to strike a balance between Digimarc Barcode durability and visibility in most images. However, you can adjust the Watermark Durability setting yourself to suit the needs of your images. Low values are less visible in an image but less durable, and may be damaged by applying filters or by performing some image editing, printing, and scanning operations. High values are more durable but may display some visible noise in the image.

Your setting should depend on the intended use of the image and the goals you’ve set for your watermarks. For example, it may be quite acceptable to use a higher Watermark Durability setting with JPEG images posted on a website. The higher durability helps to ensure the persistence of the Digimarc Barcode, and the increased visibility often is not noticeable with medium-resolution JPEG images. Digimarc recommends experimenting with various settings as part of your testing process to determine which setting works best for the majority of your images.

Check the signal strength meter

The signal strength meter helps you determine whether a Digimarc Barcode is durable enough to survive the intended use of the image.

The signal strength meter is available only for images containing a Digimarc Barcode that you yourself have applied.

Digimarc recommends that you check the signal strength meter before publishing your images. For example, if you often compress watermarked images for inclusion in a website, check the meter before posting the images. You can also use the signal strength meter to gauge the effectiveness of different Watermark Durability settings that you are experimenting with.