# Colorblind-Safe Workflows

Canonical URL: https://colorcurio.us/library/collections/colorblind-safe-workflows
Source type: Collection

> Most accessibility work focuses on text contrast, which is the easy half of the problem. These entries are about the harder half: making sure two distinct semantic categories stay distinct after a…

## Summary

Most accessibility work focuses on text contrast, which is the easy half of the problem. These entries are about the harder half: making sure two distinct semantic categories stay distinct after a CVD transform, picking sequential palettes that survive deuteranopia, and auditing palettes you have already shipped. Start with Okabe and Ito, whose eight-color set is still the safest categorical default; the Viz Palette and Color Oracle simulators are the quickest sanity checks; DaltonLens explains why some simulators lie; and ColorBrewer remains the gold standard for choropleths.

## Entries

1. [Color Universal Design (CUD)](https://colorcurio.us/library/okabe-ito-cud): A guide to figures that survive color-vision deficiency, and the source of the eight-color Okabe–Ito palette. ([source](https://jfly.uni-koeln.de/color/))
2. [Points of View: Color Blindness](https://colorcurio.us/library/wong-color-blindness): A one-page column on why red–green fails, with the Okabe–Ito set as a drop-in fix. ([source](https://www.nature.com/articles/nmeth.1618))
3. [Coloring for Colorblindness](https://colorcurio.us/library/coloring-for-colorblindness): Edit swatches and see them as protan, deutan, and tritan viewers would, with Wong, IBM, and Tol sets preloaded. ([source](https://davidmathlogic.com/colorblind/))
4. [Accessible Color Sequences for Data Visualization](https://colorcurio.us/library/accessible-color-sequences): Six-, eight-, and ten-color cycles tuned for aesthetics, CVD, and grayscale; the ten-color set ships in Matplotlib. ([source](https://arxiv.org/abs/2107.02270))
5. [Understanding WCAG Color Contrast](https://colorcurio.us/library/a11y-color-contrast): WCAG’s explanation of the 4.5:1 and 3:1 text contrast minimums, and the cases they don’t cover. ([source](https://www.w3.org/WAI/WCAG21/Understanding/contrast-minimum.html))
6. [WCAG Understanding: Use of Color](https://colorcurio.us/library/wcag-use-of-color): WCAG’s rule that information must not depend on hue alone, separate from the contrast tests. ([source](https://www.w3.org/WAI/WCAG22/Understanding/use-of-color.html))
7. [Viz Palette](https://colorcurio.us/library/viz-palette): Preview chart colors as marks and a legend, with a color-vision simulation, before you commit to them. ([source](https://projects.susielu.com/viz-palette))
8. [Color Oracle](https://colorcurio.us/library/color-oracle): A free desktop app that filters your whole screen through protan, deutan, or tritan vision. ([source](https://colororacle.org/))
9. [Sim Daltonism](https://colorcurio.us/library/sim-daltonism): A floating macOS and iOS window that simulates color-vision deficiency over whatever is beneath it. ([source](https://michelf.ca/projects/sim-daltonism/))
10. [Simulating Color Vision Deficiencies in the Blink Renderer](https://colorcurio.us/library/chrome-cvd-emulation): How to turn on CVD emulation in Chrome DevTools, and how Blink applies the Machado matrices as an SVG filter. ([source](https://developer.chrome.com/docs/chromium/cvd))
11. [Coblis Color Blindness Simulator](https://colorcurio.us/library/coblis): Upload an image and view it under each type of color-vision deficiency. ([source](https://www.color-blindness.com/coblis-color-blindness-simulator/))
12. [A Physiologically-based Model for Simulation of Color Vision Deficiency](https://colorcurio.us/library/machado-cvd-simulation): The CVD model behind most simulators, Chrome DevTools included, with severity as a dial. ([source](https://www.inf.ufrgs.br/~oliveira/pubs_files/CVD_Simulation/CVD_Simulation.html))
13. [Understanding LMS-based Color Blindness Simulations](https://colorcurio.us/library/daltonlens-cvd-simulation): How CVD simulators work — Brettel, Viénot, Machado — and where open-source versions get the math wrong. ([source](https://daltonlens.org/understanding-cvd-simulation/))
14. [Contrast Ratio Calculator](https://colorcurio.us/library/contrast-ratio): One color pair, its WCAG contrast ratio, and whether it passes for body text. ([source](https://www.siegemedia.com/contrast-ratio))
15. [APCA Contrast](https://colorcurio.us/library/apca-contrast): APCA’s perceptual lightness-contrast score, proposed as a replacement for the WCAG 2 ratio. ([source](https://apcacontrast.com/))
16. [Who Can Use](https://colorcurio.us/library/whocanuse): Enter a color pair and see which vision types can read it, and roughly how many people that is. ([source](https://www.whocanuse.com/))
17. [Colour Contrast Analyser](https://colorcurio.us/library/colour-contrast-analyser): A free Windows and macOS app: eyedrop any two on-screen colors for a WCAG contrast verdict. ([source](https://github.com/ThePacielloGroup/CCAe))
18. [Color Review](https://colorcurio.us/library/color-review): Run a palette through protan, deutan, and tritan simulations side by side. ([source](https://color.review/))
19. [Optimizing Colormaps for Color Vision Deficiency](https://colorcurio.us/library/cividis-colormap-paper): The paper behind cividis: a viridis variant tuned so color-vision deficiency doesn’t change how the scale reads. ([source](https://pmc.ncbi.nlm.nih.gov/articles/PMC6070163/))
20. [ColorBrewer 2.0](https://colorcurio.us/library/colorbrewer): Map color schemes filtered by class count, scheme type, print safety, and colorblind safety. ([source](https://colorbrewer2.org/))