Content Comparison

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Section 1.1: What are Tags?

Tags are invisible markers that carry essential information about elements within a document. They are crucial labels that help identify document elements, making them essential for assistive technologies like screen readers, which . These tools rely on this information to interpret and convey the content. For instance, a screen reader needs to know whether tags to determine if an element is a plain text paragraph, an image, or a table—and it cannot determine this unless the element is explicitly taggedtable. Without tagging, screen readers can't interpret the document's structure.

Tags provide the semantic structure that describes the content and organization of a document. This structure is communicated to assistive technologies, which in turn make it accessible to users. When every element in a document has a clear semantic meaning, screen reader users can understand its organization and navigate it effectively.

For example, sighted users can visually scan a document and move from one heading to another, even if the headings are not correctly tagged. However, screen reader users depend on these headings being explicitly and semantically tagged to recognize them as such. Proper tagging allows screen reader users to easily jump from heading to heading.

Tagging a PDF is arguably the most critical step in ensuring its accessibility. If you are familiar with HTML, PDF tagging will feel familiar since the principles are similar. If you are new to this, a bit of practice will help you become comfortable with the process.

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organization, allowing screen readers to convey the document’s layout to users. Sighted users can visually scan headings, but screen reader users need properly tagged headings to navigate efficiently.

Tagging a PDF is crucial for accessibility. If you know HTML, PDF tagging will be familiar; if not, some practice will help you understand it.

Types of Tags in Acrobat:

• Article

• Annotation

• Bibliography

• Block Quote

• Caption

• Code

• Division

• Document

• Figure

• Form

• Formula

• Heading

• Heading Level 1-6

• Index

• Label

• Link

• List

• List Item

• List Item Body

• Note

• Paragraph

• Part

• Quote

• Reference

• Section

• Span

• Table

• Table Data Cell

• Table Header Cell

• Table of Contents

• Table of Contents Item

• Table Row

Section 1.2: Remediation Flow in PDF Documents

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1. Optimize the original source document for accessibility.

2. Convert the source document into a tagged PDF.

3. Include metadata.

4. Add or adjust tags as needed.

5. Refine the reading order and tab order.

6. Verify the accessibility of your work.

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If you need to work with a poorly tagged PDF:

1. Add metadata.

2. Create or refine the tags.

3. Adjust the reading order and tab order.

4. Check the accessibility of your work.

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1. Add metadata.

2. For very simple documents, use Acrobat Pro to auto generate tags.

3. For more complex documents, manually create the tags.

4. Refine and adjust the tags as needed.

5. Optimize the reading order and tab order.

6. Evaluate the accessibility of your work.

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If starting with a paper or scanned document:

1. Scan the document, if needed.

2. Use optical character recognition (OCR) to generate searchable text.

3. Proceed with the steps for working with an untagged PDF.

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Section 1.3: PDF Accessibility Standards

WCAG (Web Content Accessibility Guidelines) provides provide rules for making web content accessible. It includes They include 78 clear, measurable criteria with clear pass/fail outcomes to help authors create accessible contentstandards. For example, text must meet have a minimum color contrast ratio against its background. If it doesn’tagainst the background—if it’s too low, it fails that criterion. WCAG defines technical requirements (success criteria), techniques for achieving methods to meet them, and additional guidance.

PDF/UA (PDF/Universal Accessibility) is the standard for making PDFs accessible, also known as ISO 14289, sets technical standards for accessible PDF documents, based . Based on WCAG 2.0 principles. Like WCAG, it includes sets specific criteria for accessibility. Shortly after its releaseTo support this, the Matterhorn Protocol was created to help software developers, authors, and editors comply with PDF/UA. It lists , outlining 31 checkpoints and with 136 failure conditions detailing how a document can fail to help developers and document authors follow PDF/UA standards.

Both WCAG and PDF/UA have significant overlap but serve slightly different purposes. Approved are similar, with some differences, but both aim to ensure an accessible user experience. Both are published by the International Organization for Standardization (ISO), they share the common goal of creating an accessible user experience.

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