30 Years of Solving the Wrong Problem: How Recolouring Tool Design Fails those with Colour Vision Deficiency
Connor Geddes, David R. Flatla, Ciabhan L. Connelly · 2023 · Proceedings of the 25th International ACM SIGACCESS Conference on Computers and Accessibility (ASSETS '23) · doi:10.1145/3597638.3608407
Summary
This paper critically examines three decades of research into recolouring tools — colour filters and daltonization algorithms designed to help people with Colour Vision Deficiency (CVD) differentiate colours — and finds that these tools fundamentally misunderstand how people with CVD actually want to be assisted. The researchers conducted two complementary studies: first, a thematic analysis of 235 posts and 1,442 comments from the r/colorblind subreddit to capture unconstrained perspectives from people with CVD about recolouring tools; second, a controlled observation study with 21 CVD participants who used the Windows 10 colour filter to complete 14 colour-related tasks (naming colours, differentiating colours, and identifying colour-based characteristics), followed by semi-structured interviews. The research is motivated by a striking gap: despite over 30 years of recolouring tool development across academia, industry (Windows, macOS, iOS, Android all ship colour filters), and community projects, no prior work had investigated how people with CVD actually use or perceive these tools. The three dominant design goals for recolouring tools have been maintaining colour naturalness, colour consistency, and enhancing colour contrast, yet evaluations have relied on author judgement, quantitative formulas, CVD diagnostic tests, or image rankings — rarely involving meaningful dialogue with CVD users themselves.
Key findings
The findings are damning for the current recolouring paradigm. From the Reddit analysis, people with CVD reported that full-screen filters create new colour confusion problems, make the world look "ugly" and "unnatural," and cannot address all colour-related challenges. Users developed workarounds the tools were not designed for, such as toggling filters on and off via keyboard shortcuts for momentary comparison rather than using them always-on as intended. In the observation study, 15 of 21 participants deviated from the intended always-on use case. Participants universally found recolouring useless for colour naming — filters distort colours so users cannot use their existing learned colour knowledge. The study identified four critical findings: (1) people with CVD rarely use recolouring in an always-on fashion; (2) recolouring is only useful for confirming suspicions about colour differences by "turning it up to 11"; (3) recolouring can destroy learned coping mechanisms by transforming known colours to unknown ones (e.g., shifting the lightness cues people use to distinguish visited from unvisited links); and (4) most people with CVD do not want their vision "fixed" — they prefer the appearance of unmodified colours and want targeted assistance only when needed. Some participants even found that a filter designed for a different CVD type worked better for them than the one matching their diagnosis.
Relevance
This paper delivers a powerful lesson for accessibility practitioners and designers: the most popular assistive approach for an entire disability category has been designed for 30 years without adequately involving the people it claims to serve. The implications extend well beyond CVD. First, for web and app designers, the research reinforces that inclusive colour design — using redundant cues like patterns, labels, shapes, and sufficient lightness contrast alongside colour — is far more effective than relying on users to apply colour filters after the fact. Second, the paper challenges the "fix the user" mentality that pervades much assistive technology design, where tools attempt to normalize disabled people's perception rather than addressing environmental barriers. Third, it demonstrates the value of on-demand, user-controlled assistance over always-on correction — a principle applicable across many disability contexts. Organizations should prioritize designing with CVD-friendly palettes and redundant visual encoding rather than assuming recolouring tools will compensate for poor colour choices.
Tags: colour vision deficiency · colour blindness · recolouring · colour filters · daltonization · visual accessibility · assistive tools · user research