AddWatermark loads a single page PDF and superimposes that page onto one or more pages in the input document.

All passwords entered into this function's properties will be visible in plain text in the Linx solution file and in the compiled .Net assembly.


Input PDF

The follow properties specify the PDF document to be loaded and modified by the operation:

Input PDF file path

Path to the PDF file.

Input authentication type

PDF files can be protected using a password or a certificate, this field indicates which type of authentication to attempt when loading the PDF.

  1. None
    The document is unprotected and can be opened immediately.
  2. Password
    The document is protected by a password.
  3. Certificate
    The document is protected by a certificate.

Certificate protected files are not supported by the "Fill form", "Sign", "Add watermark" and "Concatenate" operations.
If you need to use the operations on a certificate protected document, first remove the certificate protection using the "Change protection" operation.
The certificate must include the private key in order to be able to load the document.

Input PDF password

Password required to access the PDF file.

Input certificate source

Source to load the certificate from. (Visible when using "Certificate" authentication type.)

  1. File
    Load a certificate from a .pfx file.
  2. Store
    Load a certificate from the windows certificate store.

Input certificate file path

Path to a .pfx file containing a certificate.

Input certificate file password

Password needed to open the certificate file.

Input certificate

Certificate loaded from the windows certificate store. (Visible when using "Store" as the certificate source.)

Output PDF

The follow properties specify options for saving the PDF document after it has been modified.

Output PDF file path

Path to the PDF file to write to.


Watermark PDF filename

The path to a single-page PDF document to use as the watermark.


The pages to add the watermark to. A dash can be used to specify a range of pages, and multiple ranges can be specified if they are seperated by a comma. For example "1-3, 5" will select pages 1,2,3 and 5.
Leave this blank to add the watermark to all pages.


  1. Above original
    Draws the watermark above the existing document contents.
  2. Below original
    Draws the watermark below the existing document contents.