Add Watermark to PDF in C# - Secure Documents with Rasterization

Introduction

Need to protect your PDF documents from unauthorized copying or distribution? Adding watermarks is one of the most effective ways to secure your intellectual property, but did you know that standard watermarks can sometimes be removed with the right tools?

That’s where PDF rasterization comes in. When you rasterize a PDF page, you’re converting it from editable vectors into a flat image—making it virtually impossible to remove watermarks without destroying the document quality. This technique is especially valuable when you’re sharing sensitive documents, legal contracts, or proprietary designs.

In this guide, you’ll learn how to add watermarks to PDF files in C# using GroupDocs.Watermark for .NET—a powerful API that handles everything from simple text watermarks to advanced rasterization. Whether you’re building a document management system or just need to protect a few files, this tutorial will walk you through the entire process with working code examples.

What you’ll accomplish:

  • Add customizable text watermarks to PDF documents
  • Rasterize PDF pages for maximum security
  • Configure watermark appearance (position, rotation, opacity)
  • Save protected documents programmatically

Let’s dive in and secure those documents!

Prerequisites

Before you start adding watermarks to your PDFs, make sure you’ve got these essentials in place:

1. GroupDocs.Watermark for .NET Installation

Download and install the library from the download page. You can also grab it via NuGet Package Manager with a simple command—it integrates seamlessly with Visual Studio projects.

2. License Setup

You’ll need a valid license to use GroupDocs.Watermark in production. Here are your options:

  • Evaluation License: Get a temporary license to test all features without limitations
  • Full License: Purchase from the buy page for commercial projects

Pro tip: The trial version adds watermarks to your output, so definitely grab a temp license for development.

3. .NET Framework

Make sure you have .NET Framework 4.6.1 or higher installed. GroupDocs.Watermark also supports .NET Core and .NET 5+, so you’re covered regardless of your stack.

4. Your PDF Document

Have a PDF file ready to watermark. It can be anything—a contract, an invoice, a design mockup—as long as it’s a valid PDF format.

Quick checklist:

  • ✅ GroupDocs.Watermark library installed
  • ✅ License acquired (temporary or full)
  • ✅ .NET development environment set up
  • ✅ Sample PDF document available

Got all that? Perfect. Let’s import the necessary namespaces and get coding.

Import Namespaces

To work with GroupDocs.Watermark for .NET, you’ll need to import the required namespaces into your C# project. These namespaces give you access to the core watermarking functionality, PDF-specific features, and common utilities.

Add these using statements at the top of your C# file:

using GroupDocs.Watermark.Common;
using GroupDocs.Watermark.Contents.Pdf;
using GroupDocs.Watermark.Options.Pdf;
using GroupDocs.Watermark.Watermarks;
using System.IO;
using System;

What each namespace does:

  • GroupDocs.Watermark.Common: Core classes like Watermarker and alignment options
  • GroupDocs.Watermark.Contents.Pdf: PDF-specific content handling (the key to rasterization)
  • GroupDocs.Watermark.Options.Pdf: Configuration options for PDF watermarks
  • GroupDocs.Watermark.Watermarks: Watermark types (text, image, etc.)
  • System.IO: File path and directory operations
  • System: Basic .NET utilities

With these namespaces imported, you’re ready to start watermarking PDFs. Let’s break down the process step by step.

Step 1: Load the PDF Document

First things first—you need to load your PDF file into the Watermarker object. This is your gateway to all watermarking operations.

string documentPath = "Your Document Path";
string outputDirectory = "Your Document Directory";
string outputFileName = Path.Combine(outputDirectory, Path.GetFileName(documentPath));
var loadOptions = new PdfLoadOptions();
using (Watermarker watermarker = new Watermarker(documentPath, loadOptions))
{
    // Your code goes here
}

What’s happening here:

  • documentPath: The full path to your source PDF (e.g., "C:\\Documents\\contract.pdf")
  • outputDirectory: Where you want to save the watermarked PDF
  • outputFileName: Combines the output directory with the original filename
  • PdfLoadOptions: Tells the API you’re working with a PDF (important for format-specific features)
  • using statement: Ensures the Watermarker object is properly disposed after use—prevents memory leaks

Why load options matter:
The PdfLoadOptions class enables PDF-specific features like page rasterization. Without it, you’d only have access to generic document operations. Always use format-specific load options when you need advanced features.

Step 2: Create and Configure Your Watermark

Now for the fun part—designing your watermark. You can customize everything from the text to the rotation angle, making it subtle or bold depending on your needs.

TextWatermark watermark = new TextWatermark("Do not copy", new Font("Arial", 8));
watermark.HorizontalAlignment = HorizontalAlignment.Center;
watermark.VerticalAlignment = VerticalAlignment.Center;
watermark.RotateAngle = 45;
watermark.SizingType = SizingType.ScaleToParentDimensions;
watermark.ScaleFactor = 1;
watermark.Opacity = 0.5;

Breaking down the configuration:

  • TextWatermark: Creates a text-based watermark with your message and font

    • "Do not copy": Your watermark text (use whatever message fits your needs)
    • new Font("Arial", 8): Font family and size (experiment with different sizes for visibility)

  • HorizontalAlignment / VerticalAlignment: Centers the watermark on the page

    • Options: Left, Center, Right / Top, Center, Bottom
    • Centering is most common for full-page watermarks

  • RotateAngle: Rotates the watermark 45 degrees

    • The diagonal look is classic for “CONFIDENTIAL” or “DRAFT” stamps
    • Use 0 for horizontal text, 90 for vertical

  • SizingType: ScaleToParentDimensions makes the watermark size relative to the page

    • Great for maintaining consistency across different page sizes
    • Alternative: Absolute for fixed pixel dimensions

  • ScaleFactor: At 1, the watermark scales proportionally to the page

    • Increase to 1.5 or 2 for larger watermarks
    • Decrease to 0.5 for smaller, more subtle marks

  • Opacity: 0.5 makes the watermark 50% transparent

    • 0 = invisible (why would you?), 1 = fully opaque
    • Sweet spot is usually between 0.3 and 0.6 for readability without obscuring content

Pro tip: For legal documents, use higher opacity (0.8+) and explicit text like “CONFIDENTIAL - DO NOT DISTRIBUTE”. For drafts or previews, go lighter (0.3-0.4) so the watermark doesn’t interfere with review.

Step 3: Apply the Watermark to Your PDF

With your watermark configured, it’s time to add it to the document. You can target specific pages or apply it to the entire PDF.

PdfArtifactWatermarkOptions options = new PdfArtifactWatermarkOptions();
options.PageIndex = 0;
watermarker.Add(watermark, options);

Understanding the options:

  • PdfArtifactWatermarkOptions: PDF-specific settings for watermark placement

    • This class tells the API to treat the watermark as a PDF artifact (not editable content)

  • PageIndex = 0: Applies the watermark to the first page only

    • PDF pages are zero-indexed (0 = first page, 1 = second page, etc.)
    • Want to watermark all pages? Just remove this line or loop through pages:
      for (int i = 0; i < pdfContent.Pages.Count; i++)
{
    options.PageIndex = i;
    watermarker.Add(watermark, options);
}

  • watermarker.Add(): The method that actually applies the watermark

    • You can call this multiple times with different watermarks if needed
    • Each watermark is a separate layer

When to watermark specific pages:

  • First page only: Cover pages, title pages
  • Last page only: Legal disclaimers, copyright notices
  • Odd/even pages: Two-sided printing scenarios
  • All pages: Maximum protection for sensitive documents

Real-world example:
If you’re watermarking a 50-page contract, you might put “CONFIDENTIAL” on every page but add “DRAFT - NOT FOR EXECUTION” only on the first page to make it crystal clear.

Step 4: Rasterize the PDF Page (Maximum Security)

Here’s where the magic happens. Rasterizing converts your PDF page from editable vectors into a flat image, making it virtually impossible to remove the watermark without specialized forensic tools.

PdfContent pdfContent = watermarker.GetContent<PdfContent>();
pdfContent.Pages[0].Rasterize(100, 100, PdfImageConversionFormat.Png);

What’s happening under the hood:

  • GetContent(): Retrieves the PDF-specific content handler

    • This gives you access to advanced PDF operations like rasterization
    • Generic Watermarker doesn’t have this—you need the typed version

  • Pages[0]: Targets the first page (zero-indexed)

    • Match this to the PageIndex you used in Step 3
    • You can rasterize multiple pages in a loop

  • Rasterize(100, 100, PdfImageConversionFormat.Png): The conversion parameters

    • 100, 100: Horizontal and vertical DPI (dots per inch)
      • Higher DPI = better quality but larger file size
      • 100 DPI is good for screen viewing; use 150-300 for print
    • PdfImageConversionFormat.Png: Output format
      • Options: Png, Jpeg, Bmp, Tiff
      • PNG is lossless (best quality), JPEG is smaller (lossy compression)

Why rasterization matters for security:

When you rasterize a page, you’re essentially taking a screenshot of it and replacing the original content. This means:

  • ✅ Watermarks become part of the image—can’t be removed without editing pixels
  • ✅ Prevents copy/paste of text (since it’s now an image)
  • ✅ Protects vector graphics and fonts from extraction
  • ❌ Increases file size (images are bigger than vectors)
  • ❌ Makes text non-searchable (no longer OCR-friendly)

Trade-offs to consider:

  • Security vs. Accessibility: Rasterized pages aren’t screen-reader friendly
  • File Size: A 50-page document can balloon from 200KB to 5MB+
  • Print Quality: Lower DPI looks pixelated when printed

Best practice: Only rasterize pages that absolutely need maximum protection (e.g., pages with proprietary designs or sensitive data). Keep other pages as vectors for better accessibility and file size.

Step 5: Save Your Watermarked PDF

Almost done! The final step is saving your newly watermarked and rasterized PDF to disk.

watermarker.Save(outputFileName);

Simple, right? The Save() method writes everything to the file path you specified in Step 1 (outputFileName).

What happens during save:

  • The watermark is permanently embedded in the PDF
  • Rasterized pages are converted to images
  • All changes are committed to the new file
  • The original file remains untouched (unless you overwrite it)

Save options you might need:

If you want more control over the output, you can use SaveOptions:

// Example: Compress the output PDF
var saveOptions = new SaveOptions();
watermarker.Save(outputFileName, saveOptions);

Common save scenarios:

  • Overwrite original: Set outputFileName to documentPath (use with caution!)
  • Versioning: Append a timestamp to the filename
    string timestamp = DateTime.Now.ToString("yyyyMMdd_HHmmss");
string outputFileName = $"watermarked_{timestamp}.pdf";
  • Batch processing: Loop through multiple PDFs and save with sequential names

Pro tip: Always save to a different filename during development. You don’t want to accidentally overwrite your only copy of an important document while testing!

Why Rasterize PDF Pages?

You might be wondering: “Isn’t adding a watermark enough?” Great question. Let’s talk about why rasterization takes your document security to the next level.

The Problem with Standard Watermarks

Traditional PDF watermarks are just another layer of content—similar to how text or images are added. While they’re visible, they can be:

  • Removed with PDF editing software (even free tools)
  • Hidden by adjusting layer visibility
  • Cropped out if they’re not positioned strategically

Real-world scenario: You send a contract with a standard “CONFIDENTIAL” watermark. The recipient opens it in Adobe Acrobat, clicks the watermark, and… deletes it. Not ideal.

How Rasterization Solves This

When you rasterize a PDF page, you’re converting the entire page (including the watermark) into a single, flat image. Think of it as taking a photograph of the page—you can’t selectively remove elements from a photo without sophisticated editing.

Benefits of rasterization:

  1. Permanent Protection: Watermarks become inseparable from the content
  2. Copy Prevention: Text can’t be copied and pasted (it’s now pixels, not text)
  3. Design Security: Vector graphics and fonts can’t be extracted or modified
  4. Forensic Resistance: Even advanced tools can’t cleanly remove the watermark

When you should rasterize:

  • Legal contracts with sensitive terms
  • Proprietary designs or technical drawings
  • Financial documents with confidential data
  • Medical records or patient information
  • Pre-publication drafts of intellectual property

When you might skip rasterization:

  • Internal documents that need searchability
  • PDFs that will be printed (vectors print better)
  • Files where accessibility (screen readers) is critical
  • Documents that need to remain editable

The bottom line: If your document absolutely cannot be altered or copied, rasterization is your best defense. Just be aware of the trade-offs in file size and accessibility.

When to Use PDF Rasterization

Not every document needs the rasterization treatment. Here’s a practical guide to help you decide when it’s worth the extra processing.

✅ Perfect Use Cases for Rasterization

1. Pre-Release Confidential Materials

  • Product designs before patent filing
  • Unreleased financial reports
  • Draft contracts under negotiation
  • Why: Prevents leaks and unauthorized distribution

2. High-Value Intellectual Property

  • Architectural blueprints
  • Engineering schematics
  • Proprietary algorithms or processes
  • Why: Makes it extremely difficult to copy or reverse-engineer

3. Legal Documents in Dispute

  • Evidence submitted to courts
  • Settlement agreements
  • Non-disclosure agreements
  • Why: Ensures authenticity and prevents tampering

4. Client-Facing Preview Documents

  • Design mockups for approval
  • Sample reports or analyses
  • Demo versions of products
  • Why: Shows value without giving away editable source files

5. Compliance-Heavy Industries

  • Healthcare records (HIPAA)
  • Financial statements (SOX)
  • Government contracts (ITAR)
  • Why: Regulatory requirements often mandate non-editable formats

❌ When to Skip Rasterization

1. Internal Collaboration Documents

  • Team wikis or knowledge bases
  • Shared project plans
  • Draft proposals still being edited
  • Why: You want colleagues to search, copy, and edit content

2. Accessibility-Critical Documents

  • Public-facing reports
  • Educational materials
  • Government forms
  • Why: Screen readers need text (not images) to function

3. Print-Optimized Materials

  • Brochures and flyers
  • High-resolution posters
  • Photo books
  • Why: Vector graphics scale infinitely; rasterized images don’t

4. Lightweight Distribution

  • Email attachments with size limits
  • Mobile app documentation
  • Web-hosted user guides
  • Why: Rasterization can 5-10x your file size

Quick Decision Matrix

Document TypeWatermark OnlyWatermark + Rasterize
Internal memo✅❌
Client proposal✅⚠️ (if highly sensitive)
Legal contract⚠️✅
Public whitepaper✅❌
Confidential design❌✅
Draft for review✅❌

Pro tip: Start with watermarks only. If you discover someone has removed or edited the watermark, that’s your signal to upgrade to rasterization for future documents.

Common Issues and Solutions

Even with a straightforward API like GroupDocs.Watermark, you might run into a few hiccups. Here are the most common issues developers face—and how to fix them fast.

Issue 1: “File is Being Used by Another Process”

Symptom: Exception thrown when trying to save the watermarked PDF.

Cause: The Watermarker object wasn’t properly disposed, or another application has the file open.

Solution:

// ✅ Always use 'using' statements
using (Watermarker watermarker = new Watermarker(documentPath, loadOptions))
{
    // Your watermarking code
} // Automatically disposed here

// ❌ Avoid this pattern
Watermarker watermarker = new Watermarker(documentPath, loadOptions);
// ... code ...
watermarker.Save(outputFileName);
// File handle still open!

Additional fix: Close the PDF in Adobe Acrobat, Foxit, or any other viewer before running your code.

Issue 2: Watermark Not Visible After Rasterization

Symptom: Watermark appears before rasterization but disappears in the final output.

Cause: You rasterized the page before adding the watermark, or used a DPI too low to render the watermark clearly.

Solution:

// ✅ Correct order: Add watermark FIRST, then rasterize
watermarker.Add(watermark, options);
pdfContent.Pages[0].Rasterize(150, 150, PdfImageConversionFormat.Png); // Higher DPI

// ❌ Wrong order: Rasterizing first
pdfContent.Pages[0].Rasterize(100, 100, PdfImageConversionFormat.Png);
watermarker.Add(watermark, options); // Watermark won't be rasterized

DPI recommendation: Use at least 150 DPI for rasterization. 100 DPI might make small text or thin watermarks invisible.

Issue 3: File Size Explodes After Rasterization

Symptom: Your 200KB PDF turns into a 10MB monster.

Cause: High DPI and lossless PNG format create large image files.

Solution:

// Use JPEG for smaller files (acceptable quality loss)
pdfContent.Pages[0].Rasterize(100, 100, PdfImageConversionFormat.Jpeg);

// Or reduce DPI if print quality isn't critical
pdfContent.Pages[0].Rasterize(72, 72, PdfImageConversionFormat.Png); // Screen resolution

Trade-off guide:

  • 72-100 DPI + JPEG: Smallest files, good for web/email
  • 150 DPI + PNG: Balanced quality and size
  • 300 DPI + PNG: Print-ready but huge files

Issue 4: License Errors in Production

Symptom: Works in development but fails with “License not found” in production.

Cause: License file path is incorrect or the license wasn’t deployed with your application.

Solution:

// Set license at application startup
string licensePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "GroupDocs.Watermark.lic");
License license = new License();
license.SetLicense(licensePath);

// Verify license is valid
if (!license.IsValidLicense())
{
    throw new Exception("Invalid or missing GroupDocs.Watermark license");
}

Deployment checklist:

  • ✅ Include license file in your build output
  • ✅ Set “Copy to Output Directory” to “Copy if newer”
  • ✅ Verify file path in production environment
  • ✅ Use absolute paths or embed the license as a resource

Issue 5: Watermark Looks Blurry or Pixelated

Symptom: Text watermark appears fuzzy, especially after rasterization.

Cause: Font size too small or DPI too low for the watermark’s complexity.

Solution:

// Increase font size for better clarity
TextWatermark watermark = new TextWatermark("CONFIDENTIAL", new Font("Arial", 24)); // Larger font

// Use higher DPI when rasterizing
pdfContent.Pages[0].Rasterize(300, 300, PdfImageConversionFormat.Png); // Print quality

// Or use thicker fonts
TextWatermark watermark = new TextWatermark("CONFIDENTIAL", new Font("Arial Black", 20));

Best practices:

  • Minimum font size: 12pt for small watermarks, 18pt for diagonal stamps
  • High-contrast colors: Dark gray on light pages, white on dark pages
  • Bold or thick fonts: “Arial Black” > “Arial Light”

Issue 6: Rasterization Takes Too Long

Symptom: Processing large PDFs (50+ pages) takes several minutes.

Cause: Rasterizing every page is CPU-intensive, especially at high DPI.

Solution:

// Only rasterize critical pages
int[] criticalPages = { 0, 1, 2 }; // First three pages only
foreach (int pageIndex in criticalPages)
{
    pdfContent.Pages[pageIndex].Rasterize(150, 150, PdfImageConversionFormat.Jpeg);
}

// Or use parallel processing (advanced)
Parallel.For(0, criticalPages.Length, i =>
{
    pdfContent.Pages[criticalPages[i]].Rasterize(150, 150, PdfImageConversionFormat.Jpeg);
});

Optimization tips:

  • Rasterize only pages with sensitive data
  • Use JPEG instead of PNG (faster compression)
  • Lower DPI for internal documents (100 DPI vs. 300 DPI)
  • Batch process overnight for large document sets

Troubleshooting quick reference:

  1. Check using statements for proper disposal
  2. Verify watermark-then-rasterize order
  3. Adjust DPI/format for file size
  4. Validate license path in production
  5. Increase font size for clarity
  6. Selective rasterization for performance

Best Practices for PDF Watermarking

You’ve got the basics down—now let’s talk about how to use GroupDocs.Watermark like a pro. These best practices will help you create secure, professional-looking watermarked PDFs without common pitfalls.

1. Choose the Right Watermark Style for Your Needs

Subtle vs. Bold:

  • Subtle (opacity 0.2-0.4): Good for drafts, internal reviews, or when you want to maintain readability
  • Bold (opacity 0.7-1.0): Best for legal documents, confidential materials, or when you want the watermark to be unmissable

Text vs. Image:

  • Text watermarks: Faster to apply, smaller file sizes, easy to customize
  • Image watermarks: Use your logo, seals, or QR codes for branding or tracking

2. Optimize for Performance

Don’t rasterize unnecessarily:

// ❌ Avoid: Rasterizing every page by default
for (int i = 0; i < pdfContent.Pages.Count; i++)
{
    pdfContent.Pages[i].Rasterize(300, 300, PdfImageConversionFormat.Png); // Overkill!
}

// ✅ Better: Target specific pages
int[] sensitivePa = { 0, 5, 10 }; // Only pages with confidential data
foreach (int pageIndex in sensitivePages)
{
    pdfContent.Pages[pageIndex].Rasterize(150, 150, PdfImageConversionFormat.Jpeg);
}

Batch processing tip: If you’re watermarking hundreds of PDFs, process them in parallel or use a background job queue to avoid blocking your application.

3. Test with Different PDF Viewers

Watermarks can render differently across PDF viewers (Adobe, Chrome, Edge, mobile apps). Always test your watermarked PDFs in:

  • Adobe Acrobat Reader (desktop)
  • Google Chrome (browser)
  • Mobile PDF apps (iOS/Android)

Why this matters: Some viewers have different rendering engines that might affect watermark visibility or positioning.

4. Version Control Your Watermarked Documents

Add metadata to track when and why a document was watermarked:

// Example: Add custom metadata (if supported by your use case)
string watermarkedOn = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");
string watermarkedBy = Environment.UserName;

// You can embed this info in the filename or document properties
string versionedFilename = $"Contract_Watermarked_{watermarkedOn}_{watermarkedBy}.pdf";

This helps with auditing and compliance requirements.

5. Balance Security and Usability

Don’t over-engineer:

  • If your document is only mildly sensitive, a simple watermark (no rasterization) is often enough
  • Rasterization should be reserved for truly confidential materials

Accessibility matters:

  • If your PDFs need to be accessible (screen readers, etc.), avoid rasterizing
  • Consider adding an accessible version alongside the watermarked one

6. Handle Errors Gracefully

Always wrap your watermarking code in try-catch blocks for production use:

try
{
    using (Watermarker watermarker = new Watermarker(documentPath, loadOptions))
    {
        // Your watermarking logic
        watermarker.Save(outputFileName);
    }
}
catch (Exception ex)
{
    // Log the error for debugging
    Console.WriteLine($"Watermarking failed: {ex.Message}");
    
    // Optionally, save an unwatermarked copy or alert the user
    File.Copy(documentPath, outputFileName); // Fallback
}

Why this matters: Production environments can have unexpected issues (file permissions, disk space, corrupted PDFs). Graceful error handling prevents your application from crashing.

7. Keep Your License Up to Date

GroupDocs licenses often have expiration dates or usage limits. Set up monitoring to alert you before your license expires:

// Check license validity periodically
License license = new License();
license.SetLicense(licensePath);

if (!license.IsValidLicense())
{
    // Send alert to admin
    SendAlert("GroupDocs.Watermark license is invalid or expired!");
}

Pro tip: Use a license management service or calendar reminders to renew before expiration.

8. Document Your Watermarking Workflow

For teams or long-term projects, document:

  • Which documents get watermarked and why
  • Watermark settings (opacity, rotation, text, etc.)
  • Rasterization criteria (which pages, what DPI)
  • Approval process for watermarking sensitive documents

This ensures consistency across your organization and makes onboarding new developers easier.

Quick Checklist Before Deploying

  • ✅ Tested with multiple PDF viewers
  • ✅ Error handling implemented
  • ✅ License validity checked
  • ✅ File size optimized (DPI and format)
  • ✅ Accessibility considered
  • ✅ Workflow documented
  • ✅ Performance benchmarked (for batch processing)

Follow these best practices, and you’ll have a robust, professional PDF watermarking system that balances security, performance, and usability.

Conclusion

Adding watermarks to PDFs in C# doesn’t have to be complicated—and with GroupDocs.Watermark for .NET, you’ve got a powerful, flexible tool that handles everything from basic text watermarks to advanced rasterization for maximum security.

Here’s what you’ve learned:

  • How to load PDFs and configure customizable watermarks
  • The difference between standard watermarks and rasterized pages
  • When to use rasterization (and when to skip it)
  • Best practices for performance, security, and usability
  • How to troubleshoot common issues

Whether you’re protecting legal contracts, securing proprietary designs, or just marking drafts, this API gives you the control you need without reinventing the wheel. Start with simple watermarks for everyday documents, and save rasterization for when you absolutely need that extra layer of protection.

Next steps:

  1. Download GroupDocs.Watermark for .NET and try the examples in this guide
  2. Experiment with different watermark styles (opacity, rotation, positioning)
  3. Test rasterization on non-critical documents to see the security difference
  4. Check out the documentation for advanced features like image watermarks and batch processing

Got questions or run into issues? The GroupDocs support forum is incredibly helpful—developers and Anthropic team members actively respond to questions.

FAQ’s

Is GroupDocs.Watermark compatible with other document formats besides PDF?

Yes! GroupDocs.Watermark supports a wide range of formats including Word (DOCX), Excel (XLSX), PowerPoint (PPTX), Visio (VSDX), images (PNG, JPEG), and more. You can use the same API across different file types—just change the load options (e.g., WordProcessingLoadOptions instead of PdfLoadOptions).

Can I customize the appearance of the watermark added to the document?

Absolutely. You have full control over font, size, color, opacity, rotation angle, and positioning. You can also use image watermarks (logos, seals) instead of text. The API lets you fine-tune every visual aspect to match your branding or security requirements.

Is GroupDocs.Watermark suitable for both personal and commercial use?

Yes. GroupDocs offers flexible licensing:

  • Free trial: Test all features with evaluation watermarks
  • Temporary license: Full features for development/testing
  • Commercial license: For production use in personal projects or enterprise applications

Check the pricing page for options that fit your scale.

Does GroupDocs.Watermark offer technical support for developers?

Yes. You can access technical support through the GroupDocs forum, where developers share solutions and GroupDocs staff respond to questions. There’s also comprehensive documentation with code examples and API references.

Can I try GroupDocs.Watermark before making a purchase?

Definitely! Download a free trial to explore all features. The trial version adds watermarks to your output, but you can also request a temporary license for full functionality during evaluation—perfect for testing in your specific environment.