When you first scan a printed page to PDF, it creates a document that contains no actual text, just an image of text. Lacking any recognizable text, it does not allow interaction with reading tools, and is also difficult to read on a mobile device.

In a few short steps, software such as Adobe Acrobat Professional, Abbyy FineReader, or OmniPage can take an image-only PDF and make it "Searchable" using a process called Text Recognition, or Optical Character Recognition (OCR). The resulting document has text that you can interact with using a variety of technologies.

Benefits of a searchable PDF include the ability to:

  • Search text
  • Select text
  • Highlight text
  • Create a Table of Contents
  • Listen to text
Locate Digital Originals
Single page of text with a paragraph selected, showing that it is searchable
Example of a scanned PDF with recognized text.

When possible, avoid photocopying or scanning to PDF. If you can locate higher quality digital originals, your PDF documents stand a much better chance of being accessible.

  • Download PDFs directly from the publisher or research database.
  • Create them by converting your electronic documents directly to the PDF format.
  • Request accessible PDFs from Colorado State University’s E-Reserve service. The E-Reserve office will locate digital originals, or scan articles and book chapters and make the PDFs searchable. They will even post the PDFs directly into your online courses, and help you preserve them for future semesters.
Scanning Tips
Photocopy of two pages of a book, text blurred and missing, with handwriting
Garbage in, garbage out: example of a bad quality scan.

When it's not possible to find a digital original, or if you don't have time to utilize E-Reserves, follow these tips for making scanned PDFs inclusive.

  • Begin with a quality scan. Today’s copiers will in many cases save directly to the PDF format. Go one step further and check the advanced PDF settings for a "Searchable PDF" or "OCR" option.
  • Avoid wrinkled, torn, or faded pages, and smudged or distorted text.
  • Scan book and journal pages one-page-at-a-time.
  • If pages must be scanned side by side, pay attention to the “gutter” or margin between the pages. Text cannot be recognized by software if it isn't visible on the page.
  • Adjust the scanning resolution to at least 300 pixels or dots per inch.
  • Avoid handwriting or nonstandard fonts on the pages.

Click on Enhance Scans in the toolbar.

Enhance Scans menu in toolbar

In the Enhance Scans toolbar that opens at the top of the page, select Recognize Text, then In This File.

Recognize Text menu in the Enhance Scans toolbar

Choose from the All Pages drop-down menu to do either All Pages or a range of pages (it is better not to do longer documents all at once), then click the Recognize Text button. Once the tool finishes running, you should be able to highlight text in the document. Save the document before closing.

Recognize text dialog highlighting All Pages dropdown menu and Recognize Text button

Click on Tools at the top right of the document. When the toolbar opens on the right side of the screen, click on Recognize Text to expand the menu.

Recognize text menu

Select In this File to bring up the OCR dialog box.
Choose a radio button to do either All Pages or just the Current Page, then Click OK. (All pages could take a while on longer documents.)
Recognize text dialog box

Once this finishes running, you should be able to highlight text in the document. Save the document before closing.
Sample PDF with text highlighted

After logging into Read&Write using your CSU Microsoft or Google account, click on the Scan icon in the Read & Write toolbar:

Scan button on Read&Write toolber

In the Scan window, change to the "Scan from File" tab. Then either drag and drop the PDF onto the window, or browse to select the file you need to make searchable. The default output is PDF, so leave that as is:

Change to the "Scan from file" tab. From there, select or drag and drop files. PDF and Word Doc are the options for output.

Enter the page range you want to scan (split larger documents). Then click Scan to begin text recognition:

After selecting the file, submit using the Scan button

Read&Write will open a "Save As" window. Choose a different filename than the original file that you're converting.

You should see a message that says "OCR Scanning in Progress..." The scanning can take some time.

Screenshot OCR Scanning in Progress...

After the scan finishes, you can close Read&Write. Open the PDF in Adobe (Windows) or Preview (Mac) to verify that you can select text within the document. If so, the PDF is searchable.