Slide Deck Accessibility — Making Presentations for Everyone

Accessible presentations are not a niche requirement — they are better presentations. The practices that make slides accessible for people with visual impairments, color blindness, or cognitive differences also make slides clearer, more readable, and more professional for everyone.

Color Contrast

The most common accessibility failure in slides is insufficient color contrast between text and background.

The standard: WCAG AA requires a contrast ratio of 4.5:1 for body text and 3:1 for large text (text above 18pt). WCAG AAA requires 7:1 — worth targeting for body text when possible.

In practice:

• Black (#000000 or close) on white: passes easily (~21:1)
• White on dark navy (#1B3A6B): passes (~9:1)
• Light gray text on white: often fails — avoid this common mistake
• Medium gray text on light background: check every case

Use a free contrast checker (WebAIM Contrast Checker, Colour Contrast Analyser) before finalizing any color combination. Do not guess.

Do Not Rely on Color Alone to Convey Information

Approximately 8% of men and 0.5% of women have some form of color vision deficiency. Red-green color blindness is most common.

If your chart uses red and green to distinguish two data series, viewers with deuteranopia cannot reliably tell them apart. Solutions:

• Add labels directly to data series rather than relying on legend color alone
• Use shape or pattern differentiation in addition to color (solid vs. dashed lines, circle vs. square markers)
• Choose color palettes that are distinguishable in grayscale

Tools like Coblis (Color Blindness Simulator) or the Accessibility tab in newer versions of PowerPoint can simulate how your slides appear with different types of color vision deficiency.

Text Size and Font Choice

Minimum readable text size for projected presentations: 18pt for body text, 24pt for secondary headings, 36pt+ for titles.

Font choice matters too. Highly decorative or condensed fonts are harder to read for people with dyslexia or low vision. Stick to clean, open sans-serif or humanist serif faces. Avoid all-caps body text — it removes the ascender/descender pattern that aids word recognition.

Alternative Text for Images

For digital slide decks shared as files or embedded in web pages, images should have alt text — a text description of what the image shows. This is read by screen readers for people who are blind or have low vision.

• In PowerPoint: right-click an image → Edit Alt Text
• In Google Slides: right-click an image → Alt Text
• Describe the content and purpose, not just the subject ("Bar chart showing Q3 revenue up 23% year-over-year" not "chart")
• Decorative images with no informational value can be marked as decorative to be skipped by screen readers

Slide Reading Order

Screen readers read slides in the order elements were added, which often differs from the visual order. In PowerPoint, you can check and reorder elements via Home → Arrange → Selection Pane. Set the reading order to match the logical reading sequence of the slide.

Slide Titles

Every slide should have a unique, descriptive title. Screen reader users often navigate presentations by jumping between slide titles. A slide titled "Slide 7" or left blank provides no navigation information.

Animation and Motion

Avoid rapidly flashing content (more than 3 flashes per second — a trigger for photosensitive epilepsy). For presentations with animation, provide a version without animations for attendees who need it. In settings and conferences, announce that animations are present and offer an alternative on request.

Providing a Transcript or Notes

For recorded presentations, provide a transcript. For live presentations, consider providing the slide deck in advance to attendees who need it — this allows people with low vision or cognitive disabilities to follow along on their own device at their own pace.

Cognitive Accessibility

Cognitive accessibility is about reducing the cognitive load required to understand your slides:

• One idea per slide
• Plain language over jargon where possible
• Consistent layout patterns (audience learns to expect where the title, body, and key point will be)
• Sufficient time on each slide before advancing

Summary

Contrast ratio 4.5:1 minimum. Text at 18pt minimum. Color never the sole differentiator. Alt text on images. Unique descriptive slide titles. These practices take fifteen minutes to check and make your deck work for every audience member.

Slide-deck.io applies accessible contrast ratios and font sizes by default across all templates.