Accessible viz encodes values as redundant channels: position, pattern, label, not hue alone. Ishihara plates 1917; WCAG 2 contrast; Okabe–Ito palettes for deuteranopia.
In reports, ads and assignments it fits public dashboards, exams, print in grey, legal slides. Skip it when relying on red/green alone to mean bad/good.
Parts
- Mark — The core mark of Accessible viz is redundant channels: position, pattern, label, not hue alone.
- Scale — The scale must show zero (or a declared break) and units.
- Axis — Axis titles name the variable, not a mood.
- Legend — A legend is weaker than a direct label. Write beside the mark when you can.
- Label — Numbers are optional. If comparison is the job, label the ends only.
- Grid — Keep the grid faint. Data should own the ink.
- Annotation — One annotation sentence. Date the source.
- Frame — A thin frame. Never a 3-D box.
Variants
- Color-blind safe — Variant 1 of Accessible viz. Same encoding, different layout.
- WCAG charts — Variant 2 of Accessible viz. Same encoding, different layout.
- Non-color cues — Variant 3 of Accessible viz. Same encoding, different layout.
- Accessible viz 4 — Variant 4 of Accessible viz. Same encoding, different layout.
Labels
- Axis — On Accessible viz, make Mark readable.
- Legend — On Accessible viz, make Scale readable.
- Label — On Accessible viz, make Axis readable.
- Grid — On Accessible viz, make Legend readable.
- Annotation — On Accessible viz, make Label readable.
Accessible viz: honour redundant channels: position, pattern, label, not hue alone, and switch when relying on red/green alone to mean bad/good.