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Study guide · 4.4

Be aware of challenges and solutions for accessibility

Accessible content can be used by people with a wide range of abilities, including those with low vision, colour blindness or reading difficulties. Good contrast, suitable fonts, readable writing and meaningful alt text make content better for everyone, and the Web Content Accessibility Guidelines (WCAG) give measurable targets.

A study feature written by ExamDragon, not part of the real exam. Each heading is one of Certiport's skills for this objective.

4.4.1Explain the effects of color contrast on the visually impaired

  • Contrast is the difference in brightness between text and its background; low contrast is hard to read for people with low vision and for anyone in bright light.
  • WCAG 2.2 level AA asks for a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text (about 18 point, or 14 point bold).
  • User interface parts such as buttons, form borders and meaningful graphics need at least 3:1 against what surrounds them.
  • Never use colour alone to carry meaning, such as red for errors; add text, icons or patterns for people with colour blindness.
  • Use a contrast checker tool to measure colours instead of judging by eye.

Example: Light grey text on a white page measures about 2:1, so the designer darkens it to a grey that reaches 7:1 and adds an icon to error messages.

4.4.2Explain the importance of font size and selection

  • Body text that is too small is hard for many readers; on screens, around 16 pixels is a common comfortable starting size.
  • Choose clear fonts with distinct letter shapes; simple sans-serif fonts are widely used on screens.
  • Limit the number of fonts and avoid decorative or script fonts for body text.
  • Use real text styles for headings instead of just making text bigger, so screen readers can navigate.
  • Content should still work when users zoom to 200 percent or increase text size in their settings.

Example: A newsletter switches from a thin decorative font at 11 pixels to a clear sans-serif at 16 pixels with proper heading styles, and complaints about readability stop.

4.4.3Explain what readability is and how it is achieved

  • Readability is how easily a reader can understand text; it depends on words, sentence length, structure and layout.
  • Use plain language, common words, short sentences and the active voice; explain any necessary technical term.
  • Break text into short paragraphs with descriptive headings, lists and plenty of white space.
  • Left-align body text, keep comfortable line spacing and avoid long passages in capital letters or italics.
  • Readability checkers in many word processors estimate the reading level as a guide.

Example: A policy page rewritten with headings, bullet lists and sentences under 20 words takes staff half the time to read.

4.4.4Explain what alt text is and how it is used

  • Alt text (alternative text) is a short description of an image that screen readers read aloud and that appears if the image fails to load.
  • Describe the image's purpose and the information it carries, in context, in a sentence or so.
  • Do not start with 'image of' or 'picture of'; screen readers already announce it as an image.
  • Decorative images that add no information should be marked as decorative (an empty alt attribute on the web) so they are skipped.
  • Charts and complex diagrams need a short alt text plus a longer description or data table nearby.

Example: For a chart in a report the alt text reads 'Bar chart: sales rose in every region in 2026, with the north highest', and the data table follows below.

Key terms

WCAG
Web Content Accessibility Guidelines: the international standard for accessible digital content.
Contrast ratio
A measure from 1:1 to 21:1 of the brightness difference between two colours.
Screen reader
Software that reads screen content aloud or sends it to a braille display.
Readability
How easily text can be read and understood.
Alt text
A text alternative that describes an image for people who cannot see it.

Easy to confuse

  • Large text needs only 3:1, but normal body text needs 4.5:1 at level AA; do not apply the lower figure to everything.
  • Alt text should not be the file name or a long list of keywords.
  • Making text bold and large is not the same as using a heading style that assistive technology recognises.

After this guide: You can explain and apply contrast, font, readability and alt text practices that make content accessible.