Working with Watermarks

4 Apr 202421 minutes to read

The Essential PDF provides support to add watermark or stamp with text and images in the PDF document.

To quickly get started, add Watermarks and Bookmarks to a PDF document in .NET using the PDF Library. Please, check this video:

Adding text watermark in PDF document

The below code illustrates how to draw the text watermark in new PDF document using DrawString method of PdfGraphics class. The transparency can be applied to the text or images using SetTransparency method and rotation can be applied using RotateTransform method.

//Create a new PDF document.
PdfDocument pdfDocument = new PdfDocument();
//Add a page to the PDF document.
PdfPage pdfPage = pdfDocument.Pages.Add();
//Create PDF graphics for the page.
PdfGraphics graphics = pdfPage.Graphics;

//Set the font.
PdfFont font = new PdfStandardFont(PdfFontFamily.Helvetica, 20);
//Add watermark text.
PdfGraphicsState state = graphics.Save();
graphics.SetTransparency(0.25f);
graphics.RotateTransform(-40);
graphics.DrawString("Imported using Essential PDF", font, PdfPens.Red, PdfBrushes.Red, new PointF(-150, 450));

//Save the document into stream.
MemoryStream stream = new MemoryStream();
pdfDocument.Save(stream);
stream.Position = 0;
//Close the document.
pdfDocument.Close(true);
//Defining the content type for PDF file.
string contentType = "application/pdf";
//Define the file name.
string fileName = "Watermark.pdf";
//Creates a FileContentResult object by using the file contents, content type, and file name.
return File(stream, contentType, fileName);
//Create a new PDF document.
PdfDocument pdfDocument = new PdfDocument();
//Add a page to the PDF document.
PdfPage pdfPage = pdfDocument.Pages.Add();
//Create PDF graphics for the page.
PdfGraphics graphics = pdfPage.Graphics;

//Set the font.
PdfFont font = new PdfStandardFont(PdfFontFamily.Helvetica, 20);
//Add watermark text.
PdfGraphicsState state = graphics.Save();
graphics.SetTransparency(0.25f);
graphics.RotateTransform(-40);
graphics.DrawString("Imported using Essential PDF", font, PdfPens.Red, PdfBrushes.Red, new PointF(-150, 450));

//Save and close the document.
pdfDocument.Save("Watermark.pdf");
pdfDocument.Close(true);
'Create a new PDF document.
Dim pdfDocument As New PdfDocument()
'Add a page to the PDF document.
Dim pdfPage As PdfPage = pdfDocument.Pages.Add()
'Create PDF graphics for the page.
Dim graphics As PdfGraphics = pdfPage.Graphics

'Set the font.
Dim font As PdfFont = New PdfStandardFont(PdfFontFamily.Helvetica, 20)
'Add watermark text.
Dim state As PdfGraphicsState = graphics.Save()
graphics.SetTransparency(0.25F)
graphics.RotateTransform(-40)
graphics.DrawString("Imported using Essential PDF", font, PdfPens.Red, PdfBrushes.Red, New PointF(-150, 450))

'Save and close the document.
pdfDocument.Save("Watermark.pdf")
pdfDocument.Close(True)

You can download a complete working sample from GitHub.

The following screenshot shows the output of adding text watermark to PDF document.
Text watermark to PDF

The below code illustrates how to draw the text watermark in an existing PDF document using DrawString method of PdfGraphics class.

//Load an existing PDF document.
FileStream docStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.Read);
PdfLoadedDocument loadedDocument = new PdfLoadedDocument(docStream);
//Get first page from document.
PdfPageBase loadedPage = loadedDocument.Pages[0];
//Create PDF graphics for the page.
PdfGraphics graphics = loadedPage.Graphics;

//Set the standard font.
PdfFont font = new PdfStandardFont(PdfFontFamily.Helvetica, 20);

//Add watermark text.
PdfGraphicsState state = graphics.Save();
graphics.SetTransparency(0.25f);
graphics.RotateTransform(-40);
graphics.DrawString("Imported using Essential PDF", font, PdfPens.Red, PdfBrushes.Red, new PointF(-150, 

//Save the document into stream.
MemoryStream stream = new MemoryStream();
loadedDocument.Save(stream);
stream.Position = 0;
//Close the document.
loadedDocument.Close(true);
//Defining the content type for PDF file.
string contentType = "application/pdf";
//Define the file name.
string fileName = "Watermark.pdf";
//Creates a FileContentResult object by using the file contents, content type, and file name.
return File(stream, contentType, fileName);
//Load an existing PDF document.
PdfLoadedDocument loadedDocument = new PdfLoadedDocument(fileName);
//Get first page from document.
PdfPageBase loadedPage = loadedDocument.Pages[0];
//Create PDF graphics for the page.
PdfGraphics graphics = loadedPage.Graphics;

//Set the standard font.
PdfFont font = new PdfStandardFont(PdfFontFamily.Helvetica, 20);
//Add watermark text.
PdfGraphicsState state = graphics.Save();
graphics.SetTransparency(0.25f);
graphics.RotateTransform(-40);
graphics.DrawString("Imported using Essential PDF", font, PdfPens.Red, PdfBrushes.Red, new PointF(-150, 450));

//Save and close the document.
loadedDocument.Save("Watermark.pdf");
loadedDocument.Close(true);
'Load an existing PDF document.
Dim loadedDocument As New PdfLoadedDocument(fileName)
'Get first page from document.
Dim loadedPage As PdfPageBase = loadedDocument.Pages(0)
'Create PDF graphics for the page.
Dim graphics As PdfGraphics = loadedPage.Graphics

'Set the font.
Dim font As PdfFont = New PdfStandardFont(PdfFontFamily.Helvetica, 20)

'Add watermark text.
Dim state As PdfGraphicsState = graphics.Save()
graphics.SetTransparency(0.25F)
graphics.RotateTransform(-40)
graphics.DrawString("Imported using Essential PDF", font, PdfPens.Red, PdfBrushes.Red, New PointF(-150, 450))

'Save and close the document.
loadedDocument.Save("Watermark.pdf")
loadedDocument.Close(True)

You can download a complete working sample from GitHub.

The following screenshot shows the output of adding text watermark to an existing PDF document.
Text watermark in an existing PDF

Adding image watermark in PDF document

The below code sample illustrates how to add image watermark in PDF document, using DrawImage method of PdfGraphics class. The transparency can be applied to the text or images using SetTransparency method and rotation can be applied using RotateTransform method.

//Create a new PDF document.
PdfDocument pdfDocument = new PdfDocument();
//Add a page to the PDF document.
PdfPage pdfPage = pdfDocument.Pages.Add();
//Create PDF graphics for the page. 
PdfGraphics graphics = pdfPage.Graphics;

//Load the image as stream.
FileStream imageStream = new FileStream("Image.jpeg", FileMode.Open, FileAccess.Read);
//Image watermark.
PdfImage image = new PdfBitmap(imageStream);
PdfGraphicsState state = graphics.Save();
graphics.SetTransparency(0.25f);
//Draw the image. 
graphics.DrawImage(image, new PointF(0, 0), pdfPage.Graphics.ClientSize);

//Save the document into stream.
MemoryStream stream = new MemoryStream();
pdfDocument.Save(stream);
stream.Position = 0;
//Close the document.
pdfDocument.Close(true);
//Defining the content type for PDF file.
string contentType = "application/pdf";
//Define the file name.
string fileName = "Watermark.pdf";
//Creates a FileContentResult object by using the file contents, content type, and file name.
return File(stream, contentType, fileName);
//Create a new PDF document.
PdfDocument pdfDocument = new PdfDocument();
//Add a page to the PDF document.
PdfPage pdfPage = pdfDocument.Pages.Add();
//Create PDF graphics for the page.
PdfGraphics graphics = pdfPage.Graphics;

//Add image watermark.
PdfImage image = new PdfBitmap("Image.jpeg");
PdfGraphicsState state = graphics.Save();
graphics.SetTransparency(0.25f);
//Draw the image
graphics.DrawImage(image, new PointF(0, 0), pdfPage.Graphics.ClientSize);

//Save and close the document.
pdfDocument.Save("Watermark.pdf");
pdfDocument.Close(true);
'Create a new PDF document.
Dim pdfDocument As New PdfDocument()
'Add a page to the PDF document.
Dim pdfPage As PdfPage = pdfDocument.Pages.Add()
'Create PDF graphics for the page
Dim graphics As PdfGraphics = pdfPage.Graphics

'Add image watermark.
Dim image As PdfImage = New PdfBitmap("Image.jpeg")
Dim state As PdfGraphicsState = graphics.Save()
graphics.SetTransparency(0.25F)
'Draw the image.
graphics.DrawImage(image, New PointF(0, 0), pdfPage.Graphics.ClientSize)

'Save and close the document.
pdfDocument.Save("Watermark.pdf")
pdfDocument.Close(True)

You can download a complete working sample from GitHub.

The following screenshot shows the output of adding image watermark to PDF document.
Image watermark to PDF

The below code illustrates how to draw the image watermark in existing PDF document using using DrawImage method of PdfGraphics class.

//Load the PDF document
FileStream docStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.Read);
PdfLoadedDocument loadedDocument = new PdfLoadedDocument(docStream);
//Get first page from document
PdfPageBase loadedPage = loadedDocument.Pages[0];
//Create PDF graphics for the page
PdfGraphics graphics = loadedPage.Graphics;

//Load the image file as stream
FileStream imageStream = new FileStream("Image.jpeg", FileMode.Open, FileAccess.Read);
PdfImage image = new PdfBitmap(imageStream);
PdfGraphicsState state = graphics.Save();
graphics.SetTransparency(0.25f);
//Draw the image
graphics.DrawImage(image, new PointF(0, 0), loadedPage.Graphics.ClientSize);

//Save the document into stream
MemoryStream stream = new MemoryStream();
loadedDocument.Save(stream);
stream.Position = 0;
//Close the document
loadedDocument.Close(true);
//Defining the content type for PDF file
string contentType = "application/pdf";
//Define the file name
string fileName = "Watermark.pdf";
//Creates a FileContentResult object by using the file contents, content type, and file name
return File(stream, contentType, fileName);
//Load an existing document.
PdfLoadedDocument loadedDocument = new PdfLoadedDocument(fileName);
//Get first page from document.
PdfPageBase loadedPage = loadedDocument.Pages[0];
//Create PDF graphics for the page.
PdfGraphics graphics = loadedPage.Graphics;

//Add image watermark.
PdfImage image = new PdfBitmap("Image.jpeg");
PdfGraphicsState state = graphics.Save();
graphics.SetTransparency(0.25f);
//Draw the image. 
graphics.DrawImage(image, new PointF(0, 0), loadedPage.Graphics.ClientSize);

//Save and close the document.
loadedDocument.Save("watermark.pdf");
loadedDocument.Close(true);
'Load the document.
Dim loadedDocument As New PdfLoadedDocument(fileName)
'Get first page from document.
Dim loadedPage As PdfPageBase = loadedDocument.Pages(0)
'Create PDF graphics for the page
Dim graphics As PdfGraphics = loadedPage.Graphics

'Add image watermark.
Dim image As PdfImage = New PdfBitmap("Image.jpeg")
Dim state As PdfGraphicsState = graphics.Save()
graphics.SetTransparency(0.25F)
'Draw the image.
graphics.DrawImage(image, New PointF(0, 0), loadedPage.Graphics.ClientSize)

'Save and close the document.
loadedDocument.Save("watermark.pdf")
loadedDocument.Close(True)

You can download a complete working sample from GitHub.

The following screenshot shows the output of adding image watermark to an existing PDF document.
Image watermark in an existing PDF

Adding Watermark Annotation

A watermark annotation is used to represent graphics that are expected to be printed at a fixed size and position on a page, regardless of the dimensions of the printed page. PdfWatermarkAnnotation can be used.
The following code example explains how to add a watermark annotation in the PDF document

//Load the PDF document
FileStream docStream = new FileStream("input.pdf", FileMode.Open, FileAccess.Read);
PdfLoadedDocument loadedDocument = new PdfLoadedDocument(docStream);
//Get the page 
PdfLoadedPage lpage = loadedDocument.Pages[0] as PdfLoadedPage;

//Creates PDF watermark annotation 
PdfWatermarkAnnotation watermark = new PdfWatermarkAnnotation(new RectangleF(100, 100, 200, 50));
//Sets properties to the annotation 
watermark.Opacity = 0.5f; 
//Create the appearance of watermark 
watermark.Appearance.Normal.Graphics.DrawString("Watermark Text", new PdfStandardFont(PdfFontFamily.Helvetica, 20), PdfBrushes.Red, new RectangleF(0, 0, 200, 50), new PdfStringFormat(PdfTextAlignment.Center, PdfVerticalAlignment.Middle));
//Adds the annotation to page 
lpage.Annotations.Add(watermark);

//Save the document into stream
MemoryStream stream = new MemoryStream();
loadedDocument.Save(stream);
//Close the document 
loadedDocument.Close(true);
//Load the existing PDF document
PdfLoadedDocument loadedDocument = new PdfLoadedDocument("input.pdf");
//Get the page 
PdfLoadedPage lpage = loadedDocument.Pages[0] as PdfLoadedPage;

//Creates PDF watermark annotation 
PdfWatermarkAnnotation watermark = new PdfWatermarkAnnotation(new RectangleF(100, 100, 200, 50));
//Sets properties to the annotation 
watermark.Opacity = 0.5f; 
//Create the appearance of watermark 
watermark.Appearance.Normal.Graphics.DrawString("Watermark Text", new PdfStandardFont(PdfFontFamily.Helvetica, 20), PdfBrushes.Red, new RectangleF(0, 0, 200, 50), new PdfStringFormat(PdfTextAlignment.Center, PdfVerticalAlignment.Middle));
//Adds the annotation to page 
lpage.Annotations.Add(watermark); 

//Saves the document to disk. 
loadedDocument.Save("WatermarkAnnotation.pdf"); 
loadedDocument.Close(true);
'Load the existing PDF document
 Dim loadedDocument As New PdfLoadedDocument("input.pdf")
'Get the page 
Dim lpage As PdfLoadedPage = TryCast(loadedDocument.Pages(0),PdfLoadedPage)

'Creates PDF watermark annotation
Dim watermark As New PdfWatermarkAnnotation(New RectangleF(100, 100, 200, 50)) 
watermark.Opacity = 0.5f; 
'Creates the appearance of watermark
watermark.Appearance.Normal.Graphics.DrawString("Watermark Text", New PdfStandardFont(PdfFontFamily.Helvetica, 20), PdfBrushes.Red, New RectangleF(0, 0, 200, 50), New PdfStringFormat(PdfTextAlignment.Center, PdfVerticalAlignment.Middle))
'Adds annotation to the page 
lpage.Annotations.Add(watermark)

'Saves the document to disk. 
loadedDocument.Save("WatermarkAnnotation.pdf")
loadedDocument.Close(True)

You can download a complete working sample from GitHub.

Removing Watermark Annotation

You can remove the Watermark annotation from the annotation collection, represented by the PdfLoadedAnnotationCollection of the loaded page. The following code illustrates this.

//Load the PDF document
    FileStream docStream = new FileStream("input.pdf", FileMode.Open, FileAccess.Read);
    PdfLoadedDocument loadedDocument = new PdfLoadedDocument(docStream);
    // Iterate through the annotations collection and remove PdfLoadedWatermark annotations
    foreach (PdfPageBase page in loadedDocument.Pages)
    {
        for (int i = page.Annotations.Count - 1; i >= 0; i--)
        {
            // Check if the annotation is a PdfLoadedWatermarkAnnotation
            if (page.Annotations[i] is PdfLoadedWatermarkAnnotation)
            {
                // Remove the PdfLoadedWatermarkAnnotation
                page.Annotations.RemoveAt(i);
            }
        }
    }

    //Save the document into stream
    MemoryStream stream = new MemoryStream();
    loadedDocument.Save(stream);
    //Close the document 
    loadedDocument.Close(true);
//Load the existing PDF document
    PdfLoadedDocument loadedDocument = new PdfLoadedDocument("input.pdf");
    // Iterate through the annotations collection and remove PdfLoadedWatermark annotations
    foreach (PdfPageBase page in loadedDocument.Pages)
    {
        for (int i = page.Annotations.Count - 1; i >= 0; i--)
        {
            // Check if the annotation is a PdfLoadedWatermarkAnnotation
            if (page.Annotations[i] is PdfLoadedWatermarkAnnotation)
            {
                // Remove the PdfLoadedWatermarkAnnotation
                page.Annotations.RemoveAt(i);
            }
        }
    } 

    //Saves the document to disk. 
    loadedDocument.Save("WatermarkAnnotation.pdf"); 
    loadedDocument.Close(true);
'Load the existing PDF document
    Dim loadedDocument As New PdfLoadedDocument("input.pdf")
    ' Iterate through the annotations collection and remove PdfLoadedWatermark annotations
    For Each page As PdfPageBase In loadedDocument.Pages
        Dim i As Integer = page.Annotations.Count - 1
        While i >= 0
            ' Check if the annotation is a PdfLoadedWatermarkAnnotation
            If TypeOf page.Annotations(i) Is PdfLoadedWatermarkAnnotation Then
                ' Remove the PdfLoadedWatermarkAnnotation
                page.Annotations.RemoveAt(i)
            End If
            i -= 1
        End While
    Next

    'Saves the document to disk. 
    loadedDocument.Save("WatermarkAnnotation.pdf")
    loadedDocument.Close(True)

You can download a complete working sample from GitHub.