Evaluation of Qualitative Colour Palettes for Tactile Maps

Abstract

Much attention is currently being paid to developing universally designed solutions. Tactile maps, designed for people with visual impairments (PVI), require both graphic and tactile content. While many more- or less-official guidelines regarding tactile symbols exist, the subject literature lacks clear guidance on creating legible, highly contrasting graphic symbols for visual perception by those with residual vision. This study specifically addresses the application of colour, a key graphic variable that Is most often used to differentiate area symbols. We wanted to verify whether it is possible to choose a universal qualitative colour palette for tactile maps. We have proposed four different palettes, each with eight colours, that were later evaluated in a controlled study by 16 PVI with varying sociodemographic characteristics, using the VIEW model. The model is widely applied in the area of marketing research and considers the following aspects: Visibility, Informational, Emotional Appeal, and Workability. Our results indicate a lack of unanimity in choosing the best qualitative palette. The results of three palettes are comparable, with a subtle preference for the palette optimized for colour differences using the Python algorithm. Notably, the palette commonly used in official tactile maps in Poland received the lowest scores in every analysed dimension.