Colour is not as universal as we think
Usually we think about colours as if they have fixed meanings:
🔵 blue = trust
🟢 green = success
🔴 red = danger
🟡 yellow = warning
But research on perception and accessibility shows something much more interesting: colour is highly contextual.
The same colour can feel calming, aggressive, readable, invisible, trustworthy or stressful depending on:
surrounding colours
brightness
screen quality
environment
cognitive load
culture
age-related vision changes
And accessibility makes this even more important.
One thing that surprised me while reading more scientific research on colour perception is how unstable colour interpretation actually is:
➡️ Studies on luminance and visual perception show that readability changes significantly depending on ambient light and context. A colour combination that looks perfectly accessible in Figma can become difficult to read outdoors, on low-quality screens, or under fatigue.
➡️ Research also shows that colour-emotion associations are far less universal than digital products often assume. Red does not automatically mean danger for everyone, and blue does not automatically create trust.
➡️ Colour vision deficiency is not only about “seeing different colours”. Studies show that interfaces relying heavily on colour increase cognitive effort and make navigation, hierarchy and state changes harder to understand.
➡️ Beyond accessibility, colours directly influence cognition itself. Research in human-computer interaction found that colour impacts attention, memorisation, decision-making and perceived usability.
This is why accessibility cannot be reduced to: “does this pass WCAG contrast?”, because technically compliant colours can still create:
visual fatigue
weak hierarchy
missed actions
cognitive overload
inaccessible states in real-world conditions
The more I work on accessibility, the more I realise that colour is a cognitive communication and humans perceive it far less consistently than we tend to assume.
A few things worth checking in interfaces:
1️⃣ Can the interface still be understood in grayscale?
2️⃣ Are actions distinguishable without relying only on colour?
3️⃣ Are hover/focus states clearly visible?
4️⃣ Is contrast sufficient in realistic environments, not only on a designer’s monitor?
5️⃣ Does the interface avoid red/green dependency?
6️⃣ Is hierarchy supported by spacing and typography, not only colour?
7️⃣ Have designs been tested with colour vision deficiency simulators?
8️⃣ Is the interface still understandable under cognitive fatigue or reduced attention?
Accessible colour usage is about making sure meaning survives when colour perception changes.
