Description

Accessible Design

Documents don’t typically start off as PDFs. In most cases, source documents are first created in programs such as Microsoft Word or Adobe InDesign, and then converted into a PDF format either by the same application that created them or with Adobe Acrobat Pro.

While certain source document practices (e.g. missing heading styles) can be missed in the source document and still remediated in the PDF by Adobe Acrobat Pro, issues involving the text wording or visual design of the content must be addressed during source document creation, for example:

• Instructions in the text do not rely solely on visual cues (e.g. shape, size, visual location, orientation, or sound) (WCAG 2.0 - 1.3.3)
• Colour is not the only means of conveying information (WCAG 2.0 - 1.4.1)
• Text or images of text have sufficient contrast (WCAG 2.0 - 1.4.3)
• Text is organized with visual headings (WCAG 2.0 - 2.4.6)
• Hyperlinks make sense in the context of nearby text (WCAG 2.0 - 2.4.4)

Once you have completed the above steps, you are ready to convert your document to PDF using Adobe Acrobat Pro.

PDF tags

Tags are one of the key features of accessible PDF documents and they are similar to elements in HTML. Each tag defines the function of a particular part in the document, which can be recognized by different types of assistive technologies and communicated to users. All of the document’s pieces of content, such as headings, paragraphs, tables, images, lists, links, etc. must be “tagged”.

Without these tags, AT users may find the content and structure of documents confusing. For example, if a user is reading a document using a screen reader and comes across a table that is not properly tagged, the screen reader will read the information in the table as if it were a block of text. However, if the table is tagged properly, the screen reader will (1) let the user know that they are reading the table, and (2) differentiate between header cells and body cells and associate one with the other, making the structure much more clear to the user.

Types of PDF tags

PDF tags are similar to HTML tags, with some exceptions. We will review how to find, edit and organize these in a later lesson, but for now let's review the different types of tags that exist. There are a few broad categories of tags;

• block-level elements, which define large sections of the text, such as paragraphs, headings, and lists
• inline-level elements, such as links and quotations, which exist inside larger block-level elements and define a span of text that is different in styling or function from the surrounding text
• container elements, which are used to organize block level-elements
• special elements, such as structural table elements, and special inline-level elements.

Note: It’s not necessary to use every possible type of tag, for example a document may or may not have container elements, depending on its length and structure. Consider whether adding a particular tag or leaving one out would help a user make sense of the document.

Background

A background tag identifies components of the document that are purely decorative. This will allow AT to skip the content since it doesn’t serve a function and isn’t important. Background items are sometimes referred to as “artifacts”.

Container Elements

Container elements are used to group content elements in order to give them organizational structure and create a hierarchy.

Document

Document tag. The root element of a document’s tag tree. There can only be one document tag which contains all of the other tags.

Part

Part tag. A large part of a document, such as a page, it may contain smaller container elements, such as divs, arts, and sects.

Div

Division tag. A block-level element smaller than a part.

Art

Article tag. A self-contained piece of text.

Sect

Section tag. A general container element type, typically a section of a part or article element.

Heading and paragraph elements

P

Paragraph tag. A block-level element that defines a section of text.

H1, H2, H3, H4, H5, H6

Heading tags. A block-level element that defines a heading and it’s level within the heading hierarchy. A heading element should be the first element in any higher-level division, and always follow a hierarchical structure.

Label and list elements

Block-level elements used for tagging and structuring lists.

L

List tag. Any list of related items. All list tags should contain list item child elements.

LI

List item tag. Any one item in a list. List items must have list body elements, and may have label elements (optional).

LBL

Label tag. A bullet, name, or number that identifies and separates one item from the other in a list.

LBody

List item body tag. The descriptive content of a list item.

Special text elements

Special text elements identify text that isn’t used as a generic paragraph (P).

BlockQuote

Block quote element. One or more paragraphs of text attributed to someone other than the author of the immediate surrounding text.

Caption

Caption element. A brief portion of text that describes a table or a figure.

Index

Index element. A sequence of entries that contain identifying text and reference elements that point out the occurrence of the text in the main body of the document.

TOC

Table of contents element. An element that contains a structured list of items and labels identifying those items; has its own discrete hierarchy.

TOCI

Table of contents item element. An item contained in a list associated with a table of contents element.

Table elements

Table elements are special elements for structuring tables.

Table

Table element. A two-dimensional arrangement of data or text cells that contains table row elements as child elements and may have a caption element as its first or last child element.

TR

Table row element. One row of headings or data in a table; may contain table header cell elements and table data cell elements.

TD

Table data cell element. A table cell that contains non-header data.

TH

Table header cell element. A table cell that contains header text or data describing one or more rows or columns of a table.

Inline-level elements

Inline-level elements identify a span of text that has specific formatting or behavior. They are differentiated from block-level elements. Inline-level elements may be contained in or contain block-level elements.

BibEntry

Bibliography entry element. A description of where some cited information may be found.

Quote

Quote entry element. An inline portion of text that is attributed to someone other than the author of the text surrounding it; different from a block quote, which is a whole paragraph or multiple paragraphs, as opposed to inline text.

Span

Span entry element. Any inline segment of text; commonly used to delimit text that is associated with a set of styling properties.

Special inline-level elements

Similar to inline-level elements, special inline-level elements describe an inline portion of text that has special formatting or behavior.

Code

Code entry element. Computer program text embedded within a document.

Figure

Figure entry element. A graphic or graphic representation associated with text.

Form

Form entry element. A PDF form annotation that can be or has been filled out.

Formula

Formula entry element. A mathematical formula.

Link

Link entry element. A hyperlink that is embedded within a document. The target can be in the same document, in another PDF document, or on a website.

Note

Note entry element. Explanatory text or documentation, such as a footnote or endnote, that is referred to in the main body of text.

References

Reference entry element. A citation to text or data that is found elsewhere in the document.

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Task

Select a PDF document that contains a variety of content (lists, tables, headings). Annotate the document with tags. Don’t worry about actually adding the tags at this stage, focus on identifying all types of content and the corresponding tags. You can do this using pen and paper or your computer.

For example, the following example contains different kinds of content:

Identify all document content types consulting the list of tags above as a reference, and annotate the tags as follows (either digitally or using pen and paper):

Note: Remember that all decorative components of the document will need to be tagged as “Background”.

List the tags you applied here (for example "H1, P, L, ...") here, ensuring that the "Is this for an assignment?" dropdown is set to the name of this lesson.

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Continue to Lesson 3 - Evaluation Tools »