Creating accessible documents, including scans, is important for building courses where all students can use materials in the way best suited to their individual needs.
The foundation of an accessible scanned PDF is a high-quality image of the source document. High-quality scans are important because the process of converting the scan to searchable, editable text starts with optical character recognition (OCR) of the source text. High-quality scans allow this process to produce high-quality results.
At each multifunction printer (MFP) on campus, you'll find instructions for turning printed pages into high-quality images suitable for building accessible PDFs via OCR. Here are a few additional tips for getting the best images.
-
Clear source text
- Start with material printed in a legible font, no smaller than 12 point (even machines have trouble reading mouse type).
- There should be good contrast between the text and the background
- There should be minimal to no use of italics, bolding or other text styling.
- Avoid documents using more than two or three fonts..
- Organized Layout: The use of headings, lists, and physical white space between paragraphs and sections creates a logical, structured source for OCR.
How to optimize scanner settings
Pawprint scanners default to settings acceptable for most uses. Still, increasing the scan quality can help improve the quality of OCR on smaller, or harder-to-read text.
- To increase the scan quality, select the Scan to My Email option, then select Change Settings.
- In the settings menu, select your resolution -- expressed as Dots Per Inch (DPI). We recommend 300 DPI. Selecting a resolution above 300 DPI will produce dramatically larger files, but no appreciable increase in OCR accuracy. If you're scanning more than 50 pages at 300 DPI, you may need to break the job into multiple scans, to keep the file size down.

How to make PDFs accessible
Once you have a high-quality scan, it remains to process the file through Adobe Acrobat. At a minimum, OCR the image, tag it for structure, and set a reading order. Note: These tips are not a step-by-step manual, but a high-level overview of the process. For a fuller explanation of accessibility tools in Acrobat, see Adobe's Create and Verify Accessibility. For a deep dive into accessibility, try this course at LinkedIn Learning.
-
- OCR: First, process the document with the Scan & OCR tools. Use Recognize Text to produce searchable and editable text from the document image. This allows screen readers to access the document, and transmogrifiers like YuJa Panorama to convert the file to other formats.
-
Create and edit document structure: Using the Prepare for Accessibility Tools.
- Apply tags (Automatically Tag PDF) to build a logical document order, recognize headings and paragraphs, and set an initial reading order.
- Adjust the order in which screen readers process the document with Fix Reading Order.
- Verify accessibility status: Use Check for Accessibility in Adobe Acrobat or YuJa Panorama's Accessibility Review to identify any issues, then repair and resave.