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About this tool
Calm clinical interface palettes with five status colours, WCAG contrast scoring and a red-green colour-blindness separation audit.
The Medical Clean Palette Generator builds a low-noise interface palette for health software — surfaces, text, borders and a five-part clinical status set — and then audits it twice: WCAG 2.x contrast for every text and control pairing, and colour separation between the status colours under simulated red-green colour vision deficiency. The simulation uses the Viénot, Brettel and Mollon (1999) dichromat matrices on linear RGB, and separation is measured as CIE76 colour difference in CIELAB. It is built for teams designing EMR screens, lab result views, triage dashboards and patient apps, where a status chip being misread is a safety problem, not a style problem.
Open Medical Clean Palette Generator on AltFTool — it loads instantly in your browser.
Pick a Base hue — Clinical blue, Calm teal, Neutral slate or Sage green — and an Interface mode of Light interface or Dark interface.
Set 'Status intensity (-20 to 20)' and press Next variation to cycle Base variation 0 to 4; the palette and both audits regenerate on every change.
Read 'Status pairs still separable under red-green CVD' as a safe/total count, then Clinical statuses (Critical, Abnormal, Within range, Informational, Awaiting result) with each dot, text and soft hex, the Interface contrast table of ratios against their thresholds, and the Colour-blindness separation table of CIE76 deltas; Copy CSS exports the variables.
Contrast and colour-blindness separation are both scored, because a palette can pass one and fail the other.
Red, amber, green, blue and slate keep their meanings; only lightness and saturation are tuned per mode.
Where a vivid status colour can't carry words, a repaired sibling of the same hue is generated until it reaches 4.5:1 — darker on a light interface, lighter on a dark one.
A near-neutral base — clinical blue, teal or slate at low saturation — for everything structural, so the only saturated colour on screen carries clinical meaning. Reserve red for critical, amber for abnormal, green for within range, blue for informational and a desaturated slate for awaiting result, and never let a decorative accent share a hue with a status.
Colour vision deficiency affects roughly 8% of men and 0.5% of women of Northern European descent, and the large majority of those cases are red-green — protanopia, protanomaly, deuteranopia or deuteranomaly. In a clinical team of any size, someone will read your red and green chips differently from you, which is why this tool simulates both dichromacies.
No. WCAG 2.x SC 1.4.1 requires that colour is never the only way information is conveyed, and clinical safety guidance says the same. Pair every status colour with a text label, an icon shape or a position, so the meaning survives greyscale printing, a monochrome monitor and any degree of colour vision deficiency.
Delta E is the distance between two colours in CIELAB space; CIE76 is the plain Euclidean version. A value near 2.3 is the classic just-noticeable difference for two large patches side by side. Small chips seen apart from each other in variable lighting need far more, so this tool targets 20 under the worst simulated deficiency — a practical design threshold rather than a published standard.