TEXT & READBILITY IN WCAG 2.1

WCAG 2.1 W3C Recommendation 4 PRINCIPLES 13 GUIDELINES SOME SUCCESS CRITERIA (subset about text)

PERCEIVABLE 1.1 Text Alternatives 1.2 Time-based Media 1.3 Adaptable 1.3.1 Info and Relationships 1.4 Distinguishable 1.4.3 Contrast (Minimum) 1.4.4 Resize text 1.4.5 Images of Text 1.4.6 Contrast (Enhanced) 1.4.8 Visual Presentation 1.4.9 Images of Text (No Exception) 1.4.10 Reflow 1.4.12 Text Spacing

OPERABLE 2.1 Keyboard Accessible 2.2 Enough Time 2.3 Seizures and Physical Reactions 2.4 Navigable 2.4.6 Headings and Labels 2.5 Input Modalities

UNDERSTANDABLE 3.1 Readable 3.1.1 Language of Page 3.1.5 Reading 3.2 Predictable 3.3 Input Assistance

ROBUST 4.1 Compatible Level

Level A, AA, AAA https://www.w3.org/TR/WCAG21/ Giulia Laco – WCEU2023

*LARGE SCALE TEXT definition

Text with at least 18 point or 14 point bold or font size that would yield equivalent size for Chinese, Japanese and Korean (CJK) fonts

Fonts with extraordinarily thin strokes or unusual features and characteristics that reduce the familiarity of their letter forms are harder to read, especially at lower contrast levels.
Font size is the size when the content is delivered. It does not include resizing that may be done by a user.
The actual size of the character that a user sees is dependent both 5. on the author-defined size and the user’s display or user-agent settings. For many mainstream body text fonts, 14 and 18 point is roughly equivalent to 1.2 and 1.5 em or to 120% or 150% of the default size for body text (assuming that the body font is 100%), but authors would need to check this for the particular fonts in use. When fonts are defined in relative units, the actual point size is calculated by the user agent for display. The point size should be obtained from the user agent, or calculated based on font metrics as the user agent does, when evaluating this success criterion. Users who have low vision would be responsible for choosing appropriate settings.
When using text without specifying the font size, the smallest font size used on major browsers for unspecified text would be a reasonable size to assume for the font. If a level 1 heading is rendered in 14pt bold or higher on major browsers, then it would be reasonable to assume it is large text. Relative scaling can be calculated from the default sizes in a similar fashion.
The 18 and 14 point sizes for roman texts are taken from the minimum size for large print (14pt) and the larger standard font size (18pt). For other fonts such as CJK languages, the “equivalent” sizes would be the minimum large print size used for those languages and the next larger standard large print size.

W3C Recommendation WCAG 2.1 Giulia Laco – WCEU2023

1.4.10 REFLOW - level AA

Content can be presented without loss of information or functionality, and without requiring scrolling in two dimensions for:

Vertical scrolling content at a width equivalent to 320 CSS pixels;
Horizontal scrolling content at a height equivalent to 256 CSS pixels.

Except for parts of the content which require two-dimensional layout for usage or meaning.

NOTE Note: 320 CSS pixels is equivalent to a starting viewport width of 1280 CSS pixels wide at 400% zoom. For web content which are designed to scroll horizontally (e.g. with vertical text), the 256 CSS pixels is equivalent to a starting viewport height of 1024px at 400% zoom.

NOTE Examples of content which require two-dimensional layout are images, maps, diagrams, video, games, presentations, data tables, and interfaces where it is necessary to keep toolbars in view while manipulating content.

W3C Recommendation WCAG 2.1 Giulia Laco – WCEU2023

1.4.12 TEXT SPACING - level AA

In content implemented using markup languages that support the following text style properties, no loss of content or functionality occurs by setting all of the following and by changing no other style property: • Line height (line spacing) to at least 1.5 times the font size; • Spacing following paragraphs to at least 2 times the font size; • Letter spacing (tracking) to at least 0.12 times the font size; • Word spacing to at least 0.16 times the font size.

Exception: Human languages and scripts that do not make use of one or more of these text style properties in written text can conform using only the properties that exist for that combination of language and script.

W3C Recommendation WCAG 2.1 Giulia Laco – WCEU2023