How to add a confidential watermark to a PDF document

Adding secure non-removable, dynamic, & confidential text and image watermarks.

Adobe, Word & Office watermarks are useless because they are easily removed. Here’s how to watermark a PDF securely.

Watermarking has been utilised for centuries as a way to identify and protect currency and creative works.  Though you may think it an outdated practice, the reality is that it remains an effective way to limit counterfeiting and unauthorized sharing.  As you’ll learn throughout this guide, however, the shift towards digital watermarking makes choosing the right watermark all that more important.

We’ll be showing you how to watermark a PDF by adding a confidential watermark using PDF editing software, why watermarks are so easy to remove – and showing you how you can easily remove them, and what the solution to this problem is.  First, though, let’s start with a little rundown of what a watermarked PDF is.

  What is a watermarked PDF?

A watermarked PDF is a document in Adobe’s Portable Document Format with text, a logo, or other identifying image overlaid.  It enables you to quickly add text or images to every page of a document without having to manually edit each page.  Depending on the software used to add a watermark, the watermark may be unique to each user the PDF file is distributed to or the same across all documents.  Some PDF DRM software will let you add dynamic watermarks which inserts data dynamically when the PDF is used.

Of course, you can add a watermark using MS Word, Excel (header and footer only), PowerPoint or other applications before converting to PDF, but you get limited options on layout and opacity.  In Excel for example you can only add a watermark in the header and footer, and below are the watermark options available in MS Word.

Watermark options in Word

  What is a dynamic watermark?

A dynamic watermark is a watermark that uses variables or placeholders instead of fixed text.  When the document is viewed or printed, these variables are replaced by user or system data by the viewing application.

For example, you add a dynamic watermark such as “ONLY %username% %email% of %Company% is authorized to view this document” to the document.  When the document is viewed, the text for example will change to “ONLY Brian Giggs briangibbs@gmail.com of ACME is authorized to view this document”.

Inserting a dynamic watermark in Safeguard PDF Security

The advantage of using dynamic watermarks is that you only have to add the watermark once to a document and it is automatically customized when the document is viewed or printed.  So, let’s say you have 100 users you want to email the same PDF file to, each with their name and email address on it.  Rather than create, watermark, and distribute 100 individual PDF files, you just need to create, watermark and distribute a single one.

  What is a confidential watermark?

One of the most popular watermarks to add is a confidential watermark.  This is either text or an image that is used as a visual aid to remind users of the need to handle the document with appropriate care and not disclose it to unauthorized parties.

Here are some examples of confidential image watermarks:
confidential watermark      confidential image watermark     confidential watermark image

  Why use watermarks?

Watermarks enable you to quickly mark a document to show its status, such as a draft, confidential, etc. or to identify a user by adding their name, email, etc.  They have the advantage over putting text or images in the document header or footer in that you can place them across the page or in other layout positions.

If the viewing application supports dynamic watermarks then you can also quickly and easily customize a document with user and system information.

However, they have their problems.  Marking a document as confidential for example maybe useful for internal document distribution purposes, but if you are looking to achieve secure external document sharing then you will want to make sure that your watermarks cannot be easily removed.  Otherwise adding a watermark will not achieve much.

  How easy are watermarks to remove?

Watermarks on PDFs are generally designed to be unobtrusive yet difficult to remove with traditional photo editing tools.  This is a difficult balance to strike, as often the most effective areas for a watermark are locations where they may distract from the core text of the document.

Unfortunately, though, not all PDF watermarking solutions are equal.  The most popular way to watermark a PDF is through Adobe’s ever-dominant Acrobat software.  Though this can remain an effective (though somewhat limited) choice for printed copies, the watermarks on digital copies are trivially removed.  This is therefore not ideal if you are relying on a confidential or user identifiable watermark to help protect your documents from misuse.

We’ll be demonstrating the process of removing watermarks later on (in Acrobat, Word and photo editing tools), but first we’ll show you how to watermark a PDF with Acrobat so you can try it yourself.

  How to watermark a PDF using Adobe Acrobat DC

Though they aren’t very effective at protecting digital copies, the process to add a watermark to a PDF in Acrobat is at least simple.  You may want to use this feature to protect the print copies of a document – though bear in mind that the software lacks advanced settings such as dynamic watermarking, custom positioning, and differing watermarks for printed and digital content.

That said, if you just want the most basic confidential watermark for your print copies, here’s how you can do it:

  1. Open your document in Adobe Acrobat DC and click “Edit PDF” in the sidebar.

    Editing a PDF to insert a watermark

  2. Click “Watermark” in the top toolbar and then select “Add…”

    Adding a watermark in Adobe

  3. Select your watermark formatting options and press “OK”

    Adobe watermark options

  4. Save and/or print your watermarked document

    Saving a watermarked PDF

  How to remove a watermark from a PDF

We’ve established that adding a watermark to a document is easy, but unfortunately, they’re just as easy to remove.  This is particularly true if they aren’t password-protected.

In this section we cover how to remove a watermark using Adobe, Word, and image editing tools.

  How to remove a watermark from a PDF with Adobe Acrobat

You can remove a watermark from an unprotected Adobe PDF with almost the same process as adding one.  This makes adding a watermark to a non-protected document that you’re going to share digitally near pointless.

Unfortunately, the password can also be stripped from a document with low-cost tools, or if the user knows it (which they have to in order to open the document) – so having one is only slightly better.

Here’s how easy is it to remove a watermark:

  1. Open the PDF in Adobe Acrobat and click “Edit PDF”

    Editing a PDF to remove a watermark

  2. Click “Watermark…” in the toolbar, then press “Remove…”

    Removing a watermark in Adobe

  How to remove a watermark from a PDF using Microsoft Word

If you don’t have a copy of Adobe Acrobat DC, you can achieve a similar effect by opening a PDF file in Microsoft Word as a .docx, removing the watermark, and then saving it back as a PDF:

  1. Open your PDF file in Word

    Editing a PDF in Word to remove a watermark

  2. Press “OK” to the conversion prompt

    Converting a PDF to Word

  3. Select the watermark text and press the “Delete” key

    Removing a watermark in Word

  4. Press “Ctrl +P” and print the unwatermarked file to a PDF, or select the Save As PDF option

    Converting a Word document to PDF without watermarks

  How to remove a watermark from a PDF with Photoshop or Photopea

If a user does not have access to a PDF Editor or MS Word, they can take a screenshot of the document and remove the watermark using a photo editing tool.  If your watermark is in a location without many conflicting elements, this is quite easy due to the rise of “content-aware” tools.  This doesn’t have to be limited to expensive tools like Photoshop, either – the free online tool photopea can do it almost as well.

It’s because of this that you should take particular care when placing your watermarks:

  • Text watermarks should be placed diagonally across the page with reduced opacity.
  • Image watermarks should be used as a complete background image.

Here’s how easy it is to remove a watermark if you fail to take this into account:

  1. Open the screenshot in Photoshop or Photopea

    Editing a PDF in Photopea

  2. Select around the text using the lasso tool

    Selecting a watermark in Photopea

  3. Press “Edit > Fill” and select “Content Aware” from the dropdown. Press “OK”

    Marking the watermark selection area in Photopea

  4. Press Ctrl + D to remove the selection and inspect the result

    Removing a watermark in Photopea

As you can see, in this case, Photopea was able to seamlessly remove the watermark.  You should note, then, that even if you flatten your PDF files, replacing the pages with images, a user can remove most watermarks with a photo editing application and enough time.  Alternatively, they can use an OCR tool in Acrobat or Foxit to make your image editable again and remove the text.

This is why a properly implemented watermarking solution from a PDF DRM provider like Locklizard is so important.  Locklizard allows you to place a dynamic watermark on your PDF that’s specific to each user.  It also prevents your watermarks from being removed since neither text or image watermarks can be deleted with any of the tools mentioned above.

  How to watermark a PDF permanently with Locklizard

Protecting PDF files with non-removable watermarks

Because of Locklizard’s secure PDF viewer application and strong encryption, it’s very difficult to remove watermarks from protected PDFs.  Once encrypted, documents are converted to .pdc format which can only be opened by authorized users using the Safeguard secure PDF reader application.  This eliminates removal with third-party PDF programs, prevents OCR recognition, and disables screenshots for photo editing.

Watermarks can also be applied on a per-user basis with identifying information to further dissuade sharing.  You only need to watermark and protect the PDF once however to achieve this since dynamic variables are replaced with actual user data when the PDF is viewed or printed.  These are called dynamic watermarks because data is dynamically added when documents are viewed or printed.

Inserting a dynamic watermark in Safeguard PDF Security

However, this doesn’t mean that you should avoid watermarking best practices.  Theoretically, with enough time and effort, somebody may be able to remove a watermark from your document by taking a picture of their monitor with a camera and using a photo editing application.  Placing a watermark at the very top or bottom of the page allows them to simply crop their image to cut it out.  The same applies to printed copies, where the paper can be physically trimmed to remove the watermark.

If you want to make a watermark protected, you should consider the following:
  • Is your watermark on the edge a document, where it can be easily removed?
  • How complex is the “background” behind your watermark?  Photo editing applications make it simple to remove watermarks in front of a simple flat colour.
  • Is your watermark opaque or semi-transparent?  Semi-transparent watermarks tend to be harder to remove and interfere with the content less.
  • Are your watermarks personalised?  Generic watermarks may show the origin of a PDF, but they do little to discourage sharing.

With that in mind, here’s how to watermark a PDF by adding a confidential watermark in Safeguard PDF Security.  You can add both text and image watermarks in the same document, different watemarks for when a document is viewed and printed, or just a view or print watermark.

Adding non-removable confidential watermarks in Safeguard PDF Security

  1. Right-click on a PDF file and select “Make Secure PDF”

    Protecting PDF with watermarks

  2. Add a confidential text watermark

    Select the “View Watermarks” tab and then check the “Add Text Watermark” option.

    Adding a confidential text watermark in Safeguard Secure PDF Writer

    Type in the confidential watermark text you want to use and customize it with dynamic variables by selecting the “Editing” button.  For example, you might want to add the text “This document is confidential and is only authorized to be viewed by %UserName% %Email%”.  When a user views the document their name and email address will appear where you have inserted the dynamic variables.

    The “Position” and “Opacity” sliders are particularly important for customizing where you want the confidential watermark to be displayed and how transparent it should appear.  Pressing the monitor icon next to the position dropdown will allow you to adjust the precise position of the watermark on your page.  You can also adjust the font type, color and size and other formatting options by pressing the “Aa” button.

    Below is an example of how the text watermark is displayed when a user views the protected PDF document:

    Confidential text watermark displayed in Safeguard Secure PDF Viewer

  3. Add a confidential image watermark

    In the “View Watermarks” Image Watermark tab, check the ‘Add Image watermark’ box.

    Adding a confidential image watermark in Safeguard Secure PDF Writer

    Then browse for the confidential image watermark you want to add.  We recommend that you add a large watermark such as a background watermark so that it remains visible throughout the page as in the example below.

    Confidential watermark image

    You can change the opacity slider to make sure it remains unobtrusive.

    Below is an example of how the image watermark is displayed when a user views the protected PDF document:

    Confidential image watermark displayed in Safeguard Secure PDF Viewer

  4. Add a confidential print watermark

    If you want to allow printing then you can also add a different confidential watermark (or the same one if you prefer) when a user prints the protected PDF document.

    Customizing your print watermark independently of the digital one is generally a good idea as it can enable you to distinguish from viewed and printed copies.  You can of course apply print only watermarks if you prefer, so that a watermark is only displayed when the PDF document is printed.

    Open the “Print Watermarks” tab and adjust its options.

    Adding a print watermark in Safeguard Secure PDF Writer

    Follow the same process as for view watermarks, adding confidential text and / or a confidential image to your PDF content.

  5. Save your watermarks and other PDF security controls

    Press the “Publish” at the bottom of the PDF Writer window.

    Of course, before doing so, you should ensure that any other security controls you want to apply to your document are enabled.  By default, users cannot edit, copy or paste content, print, or take screenshots using screen capture tools.

    On pressing “Publish”, the PDF file will be encrypted and saved to your output location as a .PDC file.

  What’s the best way to watermark a PDF?

Watermarks are simple to place with tools like Adobe Acrobat, but as we’ve demonstrated, they’re just as simple to remove.  For your confidential watermarks to remain a worthwhile security measure, you need a solution that’s able to stop them being easily removed.  This means watermarking software that effectively prevents PDF editing and stops screenshots while retaining important customization options.

At the same time, the watermarks you use should be specific to the user.  Generic watermarks do little to deter sharing and make it difficult to track down the source of a leak.  Though they can be worthwhile to discern ownership after a leak, by that point the damage is already done.

Taken together, these are stringent requirements, so, understandably, generic PDF editing software is unable to achieve them.  For those businesses who want to enforce confidential and dynamic watermarks and provide the highest level of security for their documents, Locklizard PDF DRM is the only secure solution.

 

If you want to protect PDF files with non-removable watermarks, then take a free 15 day trial of our PDF DRM software.