Accessibility in Data Visualization
Accessible visualization ensures that color-vision differences, low vision, and non-visual access do not exclude readers from the data.
Access is a design requirement
A visualization that only works for readers with typical color vision on a large screen excludes a real fraction of the audience. Accessibility is not an add-on; it is part of correctness, because a figure that some readers cannot decode has failed at its job for them.
Color vision
Roughly one in twelve men has some color-vision deficiency. Never encode meaning by color alone. Pair color with shape, texture, position, or direct labels, and verify palettes under simulated deficiency. Perceptually uniform maps (see Color Maps) are largely safe by construction.
- Redundant encoding: color plus one more channel for every meaningful distinction.
- Sufficient contrast between marks and background, tested against standards.
- Legible type sizes and no reliance on hairline strokes.
Non-visual access
Charts can carry text alternatives that convey the takeaway and the data, structured tables behind the graphic, and, for the web, markup that assistive technology can read. A well-written caption stating the key finding serves everyone, including readers using a screen reader.
Motion and interaction
Respect reduced-motion preferences; do not require fine mouse control where keyboard access should suffice. Interactive tools should be operable without a pointer.
Kronos use
Public Kronos figures use redundant encoding, colorblind-safe maps, and stated takeaways so the material is legible across the widest audience.