Usually, an built-in application algorithm determines the reading order. But the reading order can be defined by the document's tag structure.

When the application is reading out a PDF using its tag structure, it utilizes the following mechanism:

• Text elements: The Alternate Text property is read aloud. If it is not available, the program reads the Current (Actual) Text property. If this is not available, the text content of the given tag will be read.
• Non-text elements (for instance, images): Since these have no text content, only two of the above steps may apply: Alternate text is read out - in its absence, Actual Text. Such PDF elements will have Alternate text if they have been created from Word documents using the proper settings in Word (Format Picture dialog, Web tab). If not, their alternate texts have to be specified manually through the Tag tab in the Properties dialog box of the element concerned.

Certain tag types are treated specially by the PDF reading feature:

• Tables: Reading first describes the table (number of columns and rows). Then table headings with the specification 'Heading'. Afterwards reading navigates through the cells following the left-to-right and top-to-bottom order. For every cell, the relevant header cell content is repeated first, before reading out the actual cell content.

• Headings: Before reading each heading, its level is defined.

• Numbered or Bullet Lists: First, the number of list elements is specified, then list elements themselves are read out.

• Form fields: When reading out uses tagging, only tagged form fields are included in it. In untagged documents, all form fields are read out - after the document content.

• Annotations: In tagged documents, only tagged annotations are read out. In untagged ones - all annotations (after form fields - if any).

These tag types are created when you generate tagged PDF files from Word using the Kofax PDF ribbon. The layout analyzer built into the product is not capable of detecting these tag types.