Colour and Contrast in Tactile Paving – Requirements under ISO 23599

This instruction is part of the SOZI EOOD expert system for tactile paving and examines the role of colour, contrast and visual perception in the design and application of tactile paving in accordance with ISO 23599 and accessibility regulations.

The colour of tactile paving is not a decorative choice. It is a functional component of the navigation system for people with visual impairments and is directly related to safety and spatial orientation.

Contrast versus “aesthetic colour”

One of the most common design errors is selecting the colour of tactile paving based solely on visual aesthetics or alignment with an interior design concept.

For tactile paving, the primary criterion is visual contrast, not colour as a tone or shade. Contrast allows tactile elements to be detected by people with low vision, residual vision or reduced contrast sensitivity.

ISO 23599 and related national regulations require clear visual differentiation between tactile paving and surrounding surfaces.

Origin of tactile paving and the role of yellow

The modern tactile paving system was developed in the 1960s in Japan by Seiichi Miyake. Its purpose was to create a universal system for safe mobility for people with visual impairments in real public environments.

He defined two fundamental tactile elements:

directional tactile indicators (guiding paths)
warning tactile indicators (attention fields)

This logic is embedded in ISO 23599 and in national accessibility standards.

Why yellow is the standard colour for tactile paving

The use of yellow is not arbitrary. It is based on research into visual perception among people with different degrees of visual impairment.

Yellow is one of the last colours to remain distinguishable as visual acuity decreases. It has high luminance and provides maximum contrast against dark, grey and neutral surfaces.

For this reason, yellow has become the international reference colour for tactile paving in public spaces.

Alternative colours – when they may be acceptable

In certain architectural or functional contexts, the use of alternative colours such as white, light grey or anthracite may be permitted.

This is acceptable only if sufficient visual contrast with the surrounding surface is ensured and the legibility of the navigation system is not compromised.

It is important to emphasise that alternative colours do not replace the standard. Yellow remains the safest and most universally reliable solution from an accessibility and safety perspective.

Typical mistakes in colour selection

choosing colours too similar to the surrounding floor
prioritising interior design over functionality
insufficient contrast in outdoor environments
mixing different colours without a clear system logic

Such mistakes compromise the navigational function of tactile paving and create safety risks for users.

Materials from the SOZI EOOD Expert System on Tactile Paving

The following publications are part of a unified expert system developed by SOZI EOOD for the proper planning, selection and application of tactile paving and tactile walking surface indicators, in accordance with accessibility requirements and applicable standards across Europe and the United Kingdom.