|Budget Amount *help
¥3,700,000 (Direct Cost : ¥3,700,000)
Fiscal Year 2000 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1999 : ¥200,000 (Direct Cost : ¥200,000)
Fiscal Year 1998 : ¥3,200,000 (Direct Cost : ¥3,200,000)
This study aims as inspecting theoretically the fastness of dyes or dyed fabrics in terms of their photochemical reactions by investigating the relationship between dye quantity and their function ; a change in colour. Acid Blue 83 was selected for experiments, because this is used for dyeing 3 grade of Blue Scale that is the standard for assessing a change in color at the test for color fastness to light. The color difference of blue aqueous solutions or of blue-dyed fabrics was measured spectometrically, and was judged visually on the following cases, A ; a decolorization model in which photo reaction products are colorless, B ; a discoloration model in which photo reaction products are yellow, and C ; an actual phenomenon accompanied with darking. The discrimination threshold of color difference and their dependence on dye quantity was analyzed.
In case of A, the discrimination threshold of color difference (ΔE) was 2〜3 in CIE L^*a^*b^* color system. This values was similar for blue and for yellow. The quantity of dye in aqueous solution and on fabric, corresponding to 2〜3ΔE, was 10 times for deep blue as that for light blue. As for yellow, the quantity of dye corresponding to 2〜3ΔE was 100 times for deep color as that for light colour. The quantity of dye required for the same color change was different with the color hue. The discrimination threshold of color difference was 6 in case of B, 9〜10 in case of C, and the corresponding quantity of dyes is also larger than that for case A.
The relationship between color fastness degree of dyed fabric and photo-reaction process of dye will be examined by measuring coefficient of color difference and quantum yield for photo-reaction of dye in film.