Comparison between Japanese and Thai visual assessments in staining and change in colour

Colour fastness is a very important factor to the quality of the dyeing of textile fabrics. The colour fastness was evaluated through visual assessment by using two types of grey scales. Although the assessments from the countries were different, it was considered necessary to find out the relationship of visual assessments in each country with the advent and wide-spread use of the internet. In order to investigate the difference between visual results assessed in Japan and abroad, we carried out an experiment using the dyed sample pairs systematically with Japanese and Thai students as observers. By comparison of the visual results, we found some differences between them. In the case of staining, a significant difference was not recognized. However, in the case of change in colour, Japanese students are severer in visual assessment than Thai students for almost all samples. A difference between assessments in the two countries was observed. In the future, with the internet shop progress, the common recognition for the colour fastness evaluation is necessary for every country. We anticipate that the visual assessment results of which are different depending on different countries will be replaced by the instrumental method.