*3.1. ColorPictogram*

With tactile sense, visually impaired people can access their works more independently, and have better tactile perception than non-visually impaired people. Baumgartner et al. [91] found that visual experience is not necessary to shape the haptic perceptual representation of materials. Color patterns are easy to understand and can be used even among people who do not share a language and culture. Braille-type color codes have been created for use on Braille devices [85]. Another method of expressing colors uses an embossed tactile pattern that is recognized by touching it with a finger [86,92–95].

Using that method, it is possible to express the shape of an object through the color pattern without deliberately creating the outline of a shape. The tactile color pictogram, which is a protruding geometric pattern, is an ideogram designed to help person with visual impairment to identify colors and interpret information through touch. Tactile sensations, together with or as an alternative to auditory sensations, enable users to approach artworks in a self-directed and attractive way that is difficult to achieve with auditory stimulation alone.

Raised geometric patterns called tactile color pictograms are ideographic characters designed to enable the visually impaired to interpret visual information through touch. Cho et al. [86] developed three tactile color pictograms to code colors in the Munsell color system; each color pattern consists of a basic cell size of 10 mm × 10 mm. In each tactile color pictogram, these basic geometric patterns are repeated and combined to create primary, secondary, and tertiary color pictograms of shapes indicating color hue, intensity, and color lightness. Each tactile color pictogram represents 29 colors including six hues, and these can be further expanded to represent 53 colors. For each of six colors (red, orange, yellow, green, blue, and purple), vivid, light, muted, and dark colors can also be expressed, along with five levels of achromatic color. These tactile color pictograms have a slightly larger cell size compared to most currently used tactile patterns but have the advantage of coding for more colors. Application tests conducted with 23 visually impaired adult volunteers confirm the effectiveness of these tactile color pictograms.

As shown in Figure 4, the graphic of colors floating into the colorless paper with two kinds of tactile color pictograms [86] represents the fact that although the artwork with the patterns looks "colorless" to a visually unimpaired person, a person with visual imparity can experience the full range and diversity of colors in the artworks.

**Figure 4.** Two tactile color pictograms, Cover image of [86], Editing Services, Wiley. Dec. 2020.
