Designing the colour appearance of textiles requires taking into account their surface properties, hairiness among others. The villi protruding on the surface not only affect the quality of textile dyeing, but also largely determine its optical properties and the colour phenomenon. The analysis of studies of optical properties shows that the influence of hairiness on the phenomenon of colour is not well understood and that the amount of hairiness at which colour changes become significant for human perception remains indefinable. In this work, we studied the change in colour characteristics depending on the change in the hairiness of woollen fabrics, comparing “yarn – raw fabric”, “yarn – raised fabric”, “raw fabric – raised fabric”. Hairiness was estimated by the hairiness index, which was obtained from the analysis of sample microphotographs of yarn and fabric using software. The value of colour characteristics (lightness, chroma and colour difference) was measured in the CIELAB colour space (1976) using a spectrophotometer. The obtained experimental results showed that the changes in lightness and saturation of textile materials from the index of its hairiness are directly proportional. However, the value of changes is different for raw and napped fabrics, undyed and dyed samples, the initial colour hue and raw material composition also making certain adjustments. This study analysed the colour difference and established the level of variation in hairiness at which the colour mismatch between woollen fabrics becomes visually noticeable. The results of the study can be used to predict the colour and design the optical properties of fabrics for weaving and finishing.

Determine the essence of the concept of «surface properties of textiles» and justify the degree of influence of the phenomenon of hairiness of textile materials on the surface properties of textile products. The analytical method is used in this work. The study contains a systematic analysis of scientific publications, the terminology of international standards and modern developments in the field of determining the surface properties of tissues. Based on the analysis of scientific research, it was found that various authors refer to the surface properties of textile materials a different set of surface effects, and their analysis through the indicators of tissue hairiness makes this issue relevant. The definition of the general term «surface» has shown that in various branches of science it is interpreted differently depending on the subject and field of study. Textile material science considers the term «supporting surface of the fabric», which needs to be clarified. Analysis of the fibrous structure of the fabric showed a complex structural organization of its surface, which is represented by the relief and various zones of the pile, formed from individual fibers having different locations on the surface of the fabric. As a result, the following terms are formulated: “fabric surface” and “surface properties of fabrics”. A list of surface properties of fabrics has been compiled, where hairiness is presented as an equivalent independent characteristic that simultaneously affects the manifestation of other surface effects. For the first time, the terms «fabric surface» and «surface properties of fabrics» are defined and justified. The nomenclature of the surface properties of fabrics is determined, based on the analysis of which it is proved that hairiness is the main characteristic of the fabric surface. The proposed terms for determining the surface of fabrics harmonize the terminology of textile materials science with other branches of science. The study of the effect of hairiness on surface properties opens up new possibilities for expanding the assortment of fabrics and is a promising area in the development of expert methods for assessing the quality of textiles.