Method of Evaluating Color of Mat Rush with a Spectrophotometer, UCHIMURA Yousuke, Shinichi FUJITOMI and Tsuyoshi SUMIYOSHI(Fukuoka Agric. Res. Cent., Chikushino, Fukuoka 818-8549, Japan)

　Method of objectively and quantitatively evaluat-ing colors of mat rushes was developed by meas-uring them with a Spectrophotometer based on (CIE 1967(L^*a^*b^*)).For measuring colors of mat rushes, the middle were found suitable. For measuring uni-form colors, the color difference and (L^*) differ-ence between the middle row and the rows 3cm away from the edge was suitable. To obtain those meas-urements with a high accuracy (within ±1by CIE1967 (L^*a^*b^*) color difference), it is necessary to measure at more than 4 locations along the middle row and at more than 8 locations along the rows located 3cm away from the edges of mat rushes. The relationship between the values gained from the measurements and those resulting from visual ob-servation was investigated to find that there was a positive relationship concerning (L^*), contrary to negative relationships concerning (b^*) and Chroma. It was found ,moreover, that there were nega-tive relationships concerning (L^*) difference and color difference ,in the case of different varie-ties and processes. Therefore, it is presumed that those measurements obtained by these methods can be sufficiently useful for evaluating colors of mat rushes. Furthermore, it was made clear that cor-rected measurements to values corresponding to(JIS Z 8721) enabled comparisons of measurements made with various colorimeters.

[Key words: CIE1976(L^*a^*b^*), evaluating, mat rush, spectrophotometer]