Changing PDF Link Color for Regulatory Submissions

Documents submitted to the FDA’s CBER and CDER must comply with the agency’s PDF specifications regarding link appearance.

Both agencies prefer blue text for hyperlinks in PDFs created from electronic source files. For scanned documents, hyperlinks should be a thin blue line.

Electronic Source File
Pic showing a link in a PDF from an electronic source.
Scanned File
Pic showing a link on a scanned PDF

If you are creating documents in Microsoft Word, it is best to style the text blue, or edit your styles to include the color, then convert to PDF.

Regulatory professionals often have to work with scanned documents, or PDFs authored outside of their control. For these documents, a post-process is required to bring link appearance into compliancy.

In this article, I’ll discuss how to change link color and style.

Link Attributes

Acrobat adds links on top of documents as clickable rectangles. The link rectangle may be invisible (the default) or visible. If the link is visible, it may have a solid or dashed border, or may appear as an underline.

Solid, dashed and underlined border attributes

It is important to understand that the link attribute does not affect the color of the underlying text. The  font color is a Text Attribute (covered in Text Attributes).

Creating Links

There are two methods to create a link in Acrobat:

  1. Select text, right-click and choose Create Link
  2. Link Tool (Tools—> Advanced Editing—> Link Tool and create a link rectangle
Tip: The Advanced Editing Toolbar contains the Link Tool. I recommend opening this toolbar and docking it to the top of the window. Choose View—>Toolbars—>Advanced Editing

You can adjust the link attributes when you initially create a link, or change them later.

Changing Link Attributes

Follow the directions below to change the link attributes to blue underlines (most appropriate for scanned documents).

  1. Choose View—>Toolbars—>Advanced Editing and choose the Link tool
    Advanced Editing Toolbar. Select the Link tool.
    All links in the document will become visible:
    When the link tool is active, links are shown on the document.
  2. To change a link Right-click on a link and choose Properties:
    Where to right click

    To change a
    single link:
    To change
    multiple links:
    To change all the links in the document:
    Double-click the link
    Hold down CTRL to select multiple links, then right-click and choose Properties. Choose the Link Tool, then choose Edit—>Select All. Type CNTRL-I or right-click and choose Properties.
  3. The Create Link window will open:
    Create Links window
    A) Change to Visible Rectangle
    B) Set Line Thickness to Thin
    C) Set Line Style to Underline
    D) Set Color to Blue
    E) Set link destination (click Next button to set


Changing Text Attributes

Text Attributes include properties such as font, size, fill color, stroke color, baseline offset and more.

It is possible to change the Text Attributes of the underlying text regardless of whether links are in place or not.

A typical use-case is to change black text to blue text to indicate links as required by the agency. Follow these steps to change the text color for existing links.

  1. Open a PDF document which was converted directly from a source, electronic file.
    (You cannot change the text attributes of scanned "Image+Text" documents. For these documents, use the Link Attributes method mentioned previously)

  2. Choose View—>Toolbars—>Advanced Editing and choose the Touchup Object Tool
    The Touchup object tool on the Advanced Editing toolbar.

    Two Tools can Modify Text Attributes
    Either the Touchup Object tool or Touchup Text tool may be used to change text attributes. The Touchup Text tool allows you to select text at the character level. Depending how the PDF was created, using the Touchup Object is often preferable. Using this tool, you can select "bounded" text such as lines, paragraphs, etc.

  3. To select an individual text element, click on it:
    Selecting an individual link
    To select several lines of text, click and drag to create a selection:
    Selecting multiple links
  4. Type CTRL-I or right-click and choose Properties
    You may receive an embedded font warning. For typical standard office fonts used in regulatory submissions, you can ignore this warning. e.g. Times, Arial, etc.

  5. The TouchUp Window opens.
    Touchup Window
    - Click on the Text tab if it is not already active.
    - Click the Fill button and change the text color to blue

  6. Click the Close button.

Final Thoughts

It is time consuming to post-process link colors and attributes. Whenever possible, make these changes in your source editing application such as Microsoft Word.

If you have a large quantity of documents to change, you might consider a plug-in for Acrobat which can automate the process.

ISI Toolbox is an Acrobat plug-in which performs over fifty useful functions for life science regulatory submissions.

Evermap’s AutoBookmark is an Acrobat plug-in which offers many useful linking and bookmarking functions.