Module 08 Activity
Scenario
Your charts work for you on your monitor. This activity checks they work for everyone else.
What you build
An accessibility and hierarchy pass: measured contrast, a safe palette, and one thing the eye reaches first.
Steps
- For every use of colour in your set, say what it encodes. Remove any that encodes nothing.
- Compute the contrast ratio for every text and element colour against its background. Fix anything under 4.5:1 for text or 3:1 for elements.
- Replace any red/green encoding. Check the replacement still separates under a colour-blindness simulation.
- Add a second channel - lightness, shape or a direct label - so no meaning rests on hue alone.
- Decide what the eye should reach first in each chart and give it the strongest available channel.
- Grey out the context series rather than deleting them, and check the chart in greyscale.
Evidence to hand in
- What each colour encodes, with the removals.
- Computed contrast ratios with any fixes.
- The replaced palette with the simulation.
- The second channel added.
- What the eye reaches first in each chart.
- The greyscale check.
Review checklist
- Every colour encodes identity, quantity or emphasis.
- Contrast ratios are computed, not judged by eye.
- No meaning rests on red versus green, or on hue alone.
- Each chart has one thing the eye reaches first, by the strongest channel.
- Every chart survives greyscale.