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Download C# .NET API for Advanced Document Watermarking

GroupDocs.Watermark for .NET is a versatile and powerful NuGet package designed to help developers seamlessly add, detect, customize, and remove watermarks in 40+ file formats, including PDFs, Word® documents, Excel® spreadsheets, PowerPoint® presentations, images, Visio® diagrams, and more. This robust API supports advanced watermarking features such as batch processing, dynamic watermark creation based on metadata, content-aware watermarking, and comprehensive security measures to protect sensitive documents. With cross-platform compatibility across Windows®, Linux, and macOS, and full support for .NET Framework, .NET Core, and .NET Standard, GroupDocs.Watermark for .NET is the ideal solution for integrating scalable watermarking capabilities into any .NET application, ensuring document integrity, brand protection, and compliance with legal standards.

Release Notes Download

Get Started

Open NuGet package manager, search for GroupDocs.Watermark and install. You may also use the following command from the Package Manager Console.

Install

To install please execute Install-Package GroupDocs.Watermark from Package Manager Console in Visual Studio to fetch & reference GroupDocs.Watermark assembly in your project.

PM>

     Install-Package GroupDocs.Watermark

Update

If you already have GroupDocs.Watermark for .Net and want to upgrade it, please execute Update-Package GroupDocs.Watermark to get the latest version.

PM>

     Update-Package GroupDocs.Watermark

.NET API for Advanced Document Watermarking

General Watermarking Features

Add Watermarks
Add text, image, or metadata watermarks to various document formats including PDFs, Microsoft Office® files, and images.

Watermark Detection
Detect existing watermarks in documents, including both text and image-based watermarks.

Watermark Removal
Remove detected watermarks while preserving the document’s original format and quality.

Watermark Management
Manage multiple watermarks within a single document, including editing, searching, and removing watermarks.

Customizable Watermark Appearance
Adjust properties such as size, color, font, opacity, rotation, and position of watermarks.

Supported Document Formats

Microsoft Office®
Watermark Word® (DOC, DOCX), Excel® (XLS, XLSX), and PowerPoint® (PPT, PPTX) files.

PDF Documents
Full support for watermarking and annotation of PDF files, including PDF/A formats.

Image Formats
Supports JPEG, PNG, BMP, TIFF, and more for image watermarking.

Visio® Diagrams
Watermark Microsoft Visio® formats such as VSD, VSDX.

OpenDocument Formats
Support for ODT, ODS, ODP, and other OpenDocument formats.

AutoCAD Files
Add watermarks to DWG, DXF formats.

Email Formats
Annotate and watermark EML, EMLX files.

HTML and HTM
Add watermarks to web-based documents.

Advanced Watermarking Capabilities

Batch Processing
Apply watermarks to multiple documents simultaneously for increased efficiency.

Content-Aware Watermarking
Apply watermarks that adapt based on the document’s content.

Dynamic Watermark Creation
Create watermarks using dynamic properties like date, time, and document metadata.

Layering and Transparency
Control the layering of watermarks, and adjust transparency to avoid obscuring content.

Conditional Watermarking
Apply watermarks based on specific triggers or document conditions.

Watermark Sensitivity
Control the sensitivity level for watermark detection.

PDF-Specific Watermarking

Page-Specific Watermarks
Apply watermarks to specific pages or all pages of a PDF document.

PDF/A Support
Fully compatible with PDF/A standards.

Password-Protected PDF Handling
Ability to add or remove watermarks in password-protected PDF files.

Microsoft Office® Watermarking

Word® Document Watermarks
Watermark Word® files across both older (97-2003) and newer (2007 and later) formats.

Excel® Sheet Watermarking
Apply watermarks to entire Excel® workbooks or specific sheets.

PowerPoint® Presentation Watermarking
Add watermarks to individual slides or entire presentations.

Image Watermarking

Multi-Frame TIFF Support
Apply watermarks to multi-frame TIFF images.

Vector Graphics Watermarks
Add scalable vector-based watermarks to images, maintaining quality upon resizing.

Security and Compliance

Document Protection
Enhance document security by adding invisible or visible watermarks to prevent unauthorized use.

Digital Signatures
Compatible with digitally signed documents, ensuring watermarking does not invalidate signatures.

Encryption Support
Apply watermarks without compromising the encryption or security of the document.

Compliance
Ensure documents meet legal and organizational standards by embedding required watermarks.

Platform and Integration

Cross-Platform Compatibility
Works across various operating systems, including Windows®, Linux, and macOS.

.NET Compatibility
Fully compatible with .NET Framework, .NET Core, and .NET Standard.

API Integration
Easily integrate with .NET applications, providing a comprehensive set of functionalities.

No External Dependencies
Operates independently without the need for third-party software installation.

Performance and Optimization

High Performance
Optimized for handling large documents and applying watermarks efficiently.

Scalable API
Suitable for large-scale watermarking tasks, capable of processing high volumes of documents.

Batch Processing
Process multiple documents in a single operation for faster watermarking.

Export and Conversion

Document Conversion
Convert watermarked documents into different formats while preserving the watermark.

Output Customization
Customize the output settings when saving watermarked documents to meet specific needs.

Supported Watermark Formats

Word: DOC, DOT, DOCX, DOCM, DOTX, DOTM, RTF
Load, Save, Add/Search/Remove watermarks

Excel: XLSX, XLSM, XLTM, XLT, XLTX, XLS
Load, Save, Add/Search/Remove watermarks

PowerPoint: PPTX, PPTM, PPSX, PPSM, POTX, POTM, PPT, PPS
Load, Save, Add/Search/Remove watermarks

Email: EML, EMLX, OFT, MSG
Load, Save — watermarking only for attachments/images

OpenDocument: ODT
Load, Save, Add/Search/Remove watermarks

PDF: PDF
Load, Save, Add/Search/Remove watermarks — not for rasterized pages

Images: BMP, GIF, JPG/JPEG/JPE, JP2, PNG, TIFF, WEBP
Load, Save, Add watermarks

Visio: VSD, VDX, VSDX, VSTX, VSS, VSSX, VSDM, VSSM, VSTM, VTX, VSX
Load, Save, Add/Search/Remove watermarks

See detailed list of file formats.

System Requirements

Supported Operating Systems

Windows

2003, 2008, 2012, 2012 R2, 2016, 2019 Servers, Vista, XP, 7, 8, 8.1, 10, Microsoft Azure

Linux

Ubuntu, OpenSUSE, CentOS, Others

Supported Frameworks

.NET Framework: 4.5.0 to 4.8
.NET Standard: 2.1
.NET Core: 3.0, 3.1
.NET: 5.0, 6.0

Development Environments

Microsoft Visual Studio: 2012, 2013, 2015, 2017, 2019, 2022

Get Started

Are you ready to give GroupDocs.Watermark for .NET a try? Simply execute Install-Package GroupDocs.Watermark from Package Manager Console in Visual Studio to fetch & reference GroupDocs.Watermark assembly in your project. If you already have GroupDocs.Watermark for .Net and want to upgrade it, please execute Update-Package GroupDocs.Watermark to get the latest version.

Please check the GitHub Repository for other common usage scenarios.

Adding a Text Watermark to a PDF Document

This code snippet demonstrates how to add a customizable text watermark to a PDF document using GroupDocs.Watermark for .NET. The text watermark includes options for setting the font, color, size, rotation, and opacity, ensuring that the watermark is prominently displayed without obscuring the document content. This feature is particularly useful for branding or protecting PDF documents from unauthorized use.

using GroupDocs.Watermark;
using GroupDocs.Watermark.Options.Pdf;

public class AddTextWatermarkToPdf
{
    public static void Run()
    {
        // Load the PDF document
        using (Watermarker watermarker = new Watermarker("input.pdf"))
        {
            // Create a text watermark with customizable properties
            TextWatermark textWatermark = new TextWatermark("Confidential", new Font("Arial", 36));
            textWatermark.ForegroundColor = Color.Red;
            textWatermark.Opacity = 0.5;
            textWatermark.RotationAngle = 45;

            // Add the watermark to all pages of the PDF
            watermarker.Add(textWatermark);
            
            // Save the watermarked PDF document
            watermarker.Save("output.pdf");
        }
    }
}

Removing an Existing Watermark from a Word® Document

This code snippet illustrates how to detect and remove existing watermarks from a Microsoft Word® document (DOCX) using GroupDocs.Watermark for .NET. This feature is essential for users who need to clean up documents by removing unwanted or outdated watermarks, ensuring the document remains professional and clear of any distracting marks.

using GroupDocs.Watermark;
using GroupDocs.Watermark.Options.Word&reg;;

public class RemoveWatermarkFromWord&reg;
{
    public static void Run()
    {
        // Load the Word&reg; document
        using (Watermarker watermarker = new Watermarker("input.docx"))
        {
            // Search and remove all watermarks from the document
            watermarker.Remove(WatermarkSearchCriteria.Text("Confidential"));
            
            // Save the document without the watermark
            watermarker.Save("output.docx");
        }
    }
}

Applying an Image Watermark with Transparency to a Presentation

This code snippet demonstrates how to add an image watermark with adjustable transparency to a PowerPoint® presentation (PPTX) using GroupDocs.Watermark for .NET. Image watermarks are ideal for adding logos or brand images to presentations, ensuring that the visual identity of the organization is maintained while allowing the underlying content to remain visible.

using GroupDocs.Watermark;
using GroupDocs.Watermark.Options.Presentation;

public class AddImageWatermarkToPptx
{
    public static void Run()
    {
        // Load the PowerPoint&reg; presentation
        using (Watermarker watermarker = new Watermarker("input.pptx"))
        {
            // Create an image watermark with transparency settings
            ImageWatermark imageWatermark = new ImageWatermark("logo.png");
            imageWatermark.Opacity = 0.3;
            imageWatermark.ScaleFactor = 0.5;
            imageWatermark.HorizontalAlignment = HorizontalAlignment.Center;
            imageWatermark.VerticalAlignment = VerticalAlignment.Center;

            // Add the watermark to all slides of the presentation
            watermarker.Add(imageWatermark);
            
            // Save the watermarked presentation
            watermarker.Save("output.pptx");
        }
    }
}

Direct Download

GroupDocs.Watermark for .NET 26.6 (DLLs only)

This ZIP file contains only the GroupDocs.Watermark for .NET assemblies. The assemblies are the same as in the MSI installer of the product of the same version. Download this if you want to use GroupDocs.Watermark for .NET without the MSI installer. This ZIP download does not contain the demo projects.

Added: 24/6/2026 Downloads: