Watermarking an image that is placed into InDesign is often as simple as figuring out the size that image is placed at, applying that sizing information to the image, watermarking, saving a copy and updating the image link.

Sometimes it's not that easy.

This sample page has a number of boots on it that would be somewhat difficult to watermark individually since the images are not only on the small size, but also "thin". The watermark would have to be very strong to be readable and could cause some visual noise. Ideally watermarking some of the surrounding background around each boot would improve readability and allow for a lighter watermark. The problem is that each boot is outlined and the background is a blend from InDesign. If there are additional InDesign image effects like multiply or opacity changes these would have to be added to the images that are watermarked.

Manually rebuilding the gradient background and images in a Photoshop file would be time consuming, but InDesign can do much of the work for you.

1. You need to make 2 layers in InDesign, one for everything we want to watermark and the other for everything we don't want to watermark like the type. Just like the sample page. 
2. Next turn off the layer we don't want to watermark and export the remaining artwork layer as a PDF or JPEG.  View this photo
   • I like the JPEG export since it will be the size of the layout and can include the bleed. 
   • Export at maximum image quality, CMYK at 300 dpi, include the profile and anti-alas the artwork.  View this photo
3. Open the exported JPEG in Photoshop. 
4. It's a simple matter to create selections of the different boots including some of the surrounding area and make them each a layer.  View this photo
5. Watermark each layer with the correct service.
6. Save the file, I save these as Photoshop files with layers.
7. Place the file back into InDesign, preferably on a new layer just about the export layer. View this photo
   
   • Since the image is the same size as the document the placement is a 0,0 offset from the top left corner or less the additional bleed in the document.

All that's left is to test the readability and to make sure the images are linked to the correct payoffs.

As with most specializations terms and acronyms are often borrowed or created ending up with modified meanings. Much of the terminology that is used for watermarking printed materials comes from print production with minor if any modifications. That being said not everyone has a printing background and some borrowed terms might need clarification due to these expanded definitions.

OSP - Digimarc Online Services Portal - the service has 2 functions:

• Provides a simple database to manage your projects, em>services and payoffs.

  • Project - Folders used by the OSP to organize your services for a particular project such as "Our June issue recipes" or "My client's local scavenger hunt".

  • Services - This is a record that has a description of what is to be watermarked and the payoff response for that watermark.

  • Payoffs - This is what the person using a watermark reader application will see. Payoffs are usually URLs that connect to a web link that can be a recipe, video, coupon or any mobile engagement that is considered rewarding. These need to be rewarding so your customer will want to re-engage and/or share with others.

• Provides image and audio watermarking tools.

  • Watermarking or Embedding - Mostly interchangeable when referring to Digimarc's process for imperceptibly modifying an image or audio data file. These modifications allow a scanning devices (your mobile phone, etc.) to read the watermark when it is presented as analog output: printed, displayed or through speakers.

  • Read - The process an application does when it detects, decodes and provides a response to a watermarked file.

  • MRC - File extension and general term for files that are used by the Photoshop plug-in embedder. The MRC file is loaded into the Mobile Watermark Embedder filter (AKA the embedder plug-in) in Photoshop and provides the data for a watermarked file to link to your service and the payoff on the OSP.

Printing terms that are used when watermarking/embedding a file. These are very simple explanations and web sources like Wikipedia can provide greater detail.

• DPI/PPI - Dots per inch for analog (printers) devices and pixels per inch for digital devices (displays and digital cameras). This is the resolution that a device or a bitmapped (digital) image uses when it is reproduced.

  • For watermarking images that are 300dpi at the size they are printing is recommended.

• LS - Line screen, used by a printing press for printing color images. Line screens allow color printing plates to place process inks close together in a controlled pattern when reproducing a color image.

  • Traditional LS screening can be used for a general characterization of the quality of printing, e.g. 65-85ls are used for newsprint and have a course image quality, higher LS usually offer better image quality; a coffee table book can be 200ls or greater.

• FM - Frequency modulated screening (often referred to as stochastic) creates dithering patterns used to reproduce color images for ink jets or some commercial presses.

  • Typically stochastic, and hybrids using FM screening with traditional LS, are indications of a fairly high quality image reproduction.

  • The direct effect color screening has on the watermark is its relationship to image reproduction. Watermarking works with newsprint or for coffee table books, its just a matter of adjusting the watermarking strength for the quality of the printing (image reproduction).

• Color Mode - Color model or color space, usually considered interchangeable, is the image in color and for watermarking in either RGB or CMYK.

  • The RGB color model uses light to create colors, your display is RGB.

  • CMYK - 4C process - uses pigments to produce colors, most printed color images are CMYK.

  • OSP watermarking is optimized for 4C (CMYK) process printing.

• Resizing and resample - These are two very different ways to change the size of an image. A previous blog, http://blog.digimarc.com/images/2009/04/the-difference-between-resize-and-resample.html#.UZ_e1pVVWPU, goes into greater detail.

As you get artwork ready for watermarking and a pressrun you have ask "How do I know it'll work"? 

There are 3 items/interactions that effect the readability of your watermarked image when it is printed:

1. How well can the reading device that your user has "see" the watermark, including in low light?
2. Image reproduction e.g. how good is you press at reproducing your artwork?
3. Did you watermark your artwork/image effectively for it's size, color space and type of image?

The good news is that all 3 of these can be determined with smartphone and a good proof.

1. Your reader's mobile device

This determines your users' experience, the reading device for testing should be at the lower end of what you expect them to use. The logic is simple, if it works with this device it'll work even quicker with a better device.

A good choice for a test device is an older mobile device; one with a fixed focus camera or older sensor and preferably without a flash. Currently the iPhone 3GS is a good choice since it was launched in 2008 so the older camera sensor, slower autofocus and lack of flash are showing its age. Additionally Apple sold a lot of them so they really do make a good testing standard for your payoff videos, web pages, etc. as well.

2. A good proof

Some proofs are better than others:

• Press proofs are the best since these include processing your art through the same workflow as the final pressrun. 
  • This isn't always possible for most users, but if you are at a publication consider adding watermarked artwork without identifying them to the public into your workflow prior to going live, a silent test.
• Calibrated film and digital proofs that match a press color and quality work very well.
• Non-calibrated color prints (home-office ink-jet, toner or dye-sub printers) should only be used if their differences from final press printing are known.*

3. Testing

• Lighting effects readability so find an area that has relatively low light without a direct lighting source. 
  • If you have a light meter somewhere around 100-120 Lux is the goal.
  • Similar to the testing device logic, if your testing device can read the watermark without a flash in low lighting it'll work great every where else. 
  • If you are watermarking menus for low lighting situation, e.g. restaurants and bars, you may want to test in an even darker set-up.
• Use your test device to read the watermarked artwork in various parts of the watermarked image. 
  • Focus on the elements that you reader will, a face or prominent product, etc. 
  • You'll want to read the watermark in about 3-6 seconds. 
  • Remember this is intended to be a "worst case" scenario so readability will only get better.

Adjust your watermarking strength if needed. You check for other blog posts or your account's Help and Resources tab if you need help with readability.

*Proofing notes

• Initially you really need to use calibrated proofs to make sure your readers get the best experience.
  • Once you have a number of printed and calibrated proofs with watermarks that work you can compare these against an in-house proofing device if needed.
  • This includes checking readability and visibility in different parts of the images, e.g. dark shadow areas, skies transitioning into white, etc.
  • If your in-house printer does a reasonably good proof and you know it's weak points you can use it as a good intermediate proofing system.
  • Obviously you need to have a lot of confidence to use it for a final for a pressrun.
• Avoid using a soft-proof (AKA one that's on your display) for anything more than testing your payoff. Your display will make it easier to read a watermark as long as the scale is correct, but this no relationship to how well it will read when printed.

The Gutenburgpress clip art can be found at http://etc.usf.edu/clipart/44800/44880/44880_guten_press_lg.gif

A first time user sometimes finds that after watermarking an image they can't read the watermark when they print it. Most often this is caused by watermarking the image at a size that is different than the size it is printed. This often happens with digital camera images since these are often at 72dpi, e.g. an iPhone 4 image is 36" x 27" at 72dpi.

The Fix:

Photoshop or other image editing applications can simply resize or resample an image to size you want to print at.

Those who don't have Photoshop and using the Portal's "Process Image" option (a Java app) can also alter an image's size. When the embedder is opened and an image is loaded you can select the "Change Print Size" button in the lower left corner. This will allow you to resize an image based on its available data to a size closer to the size you are printing. Ideally you want your image to be watermarked within 5-10% of the size it will be printing.

So why does size matter?

No doubt you've noticed that most barcodes are a fixed size. This allows a barcode reader to easily resolve the structure of a barcode and read its payload. A watermark within an image has a structure for a mobile device's camera to resolve and read its payload as well.

When a watermark is applied to an image that is 8" x 10" at 300 dpi and then printed at 8" x 10" mobile devices can easily read the watermark between 3" to 7", different mobile devices have different focal distances. If this same image is scaled to 200% (16" x 20") when printed then a mobile device has to be held twice as far as normal (6" to 14") to read it.

At a 50% size (4" x 5") the distance is reduced by 50% (1.5" to 3.5"), this is a double whammy. Not only does the mobile device need to be held closer than usual, but most mobile device's cameras have trouble focusing and resolving images at close range.

To learn more check out these blog posts on Image Resolution and on Image Resizing and Resampling.

In 2012, there were 8,448 mobile activations printed in the calendar year in the Top 100 Magazines.

• 82% on Ads (6,962)
• 18% on Edit (1,486)

These are the top Mobile Response Codes in the Top 100 Magazines.

Here’s the Post Scan experiences in the Top 100 Magazines.