Visual contrast: How well do we measure it?

Grey steps with no contrast nosing blends into the grey paving.
Grey steps leading to a grey footpath.

Visual contrast, or luminance contrast, is a key feature of universal design, but how well can we measure it? It’s a mainstream issue and something designers need to consider from the outset. It’s one thing to know the importance of visual contrast, but knowing how to measure it is another.

The glare from the doorway backlights the sign to the toilets which is mounted near the ceiling and hard to see.
Backlight makes toilet sign hard to see

Penny Galbraith explained the issues in her presentation at UD2021 Conference. For most people, vision is their most dominant sense. About 80% of our perception, learning, cognition and activities use visual cues. Contrast helps us detect objects from the background and to perceive distance. Inadequate contrast leads to confusion and difficulty negotiating the environment, even if only temporarily.  Australian Standards require a certain level of luminance contrast in the built environment. But most access consultants use their own eyes as the measuring tool. Is this good enough? Probably not.

A shopping mall with a shiny floor reflecting rows of lights from the ceiling. It looks very confusing.
A photo shows the confusing visual cues

Penny took delegates through the two main measuring instruments and there is good reason for not using them. One is costly and the other is heavy and bulky. Then she introduced a free app for a smart phone called Get Luminance. While there is still more work to do on establishing the validity of the app, it gives a better guide than a guess by eyesight.

There is much to consider in Penny’s presentation and paper and it is good to see that there is a solution. Photographs are two dimensional and often provide an indication of poor contrast. If the place is unfamiliar it is sometimes difficult to make out certain features. For example, a stainless steel sign against a concrete wall. 

Recommended reading for all access consultants and anyone approving designs for the built environment.