福岡県農業総合試験場研究報告

分光測色計を用いた畳表原料イグサからの畳表色調の「青味」および「白味」程度の推定

［摘要］畳表色調の慣行的な表現法である「青味」および「白味」の程度を、分光測色計を用いて、泥染め・乾燥した原料イグサ（以下、原草）の色調から簡易に推定する方法を検討した。分光測色計による原草の色調測定法について、120cm以上の長さで選別した原草中央部を測定する際、加重を与えない方が安定した結果が得られ、また、ａ^＊値の変動係数から算出した測定回数は20回であった。原草は畳表に対して色調が感覚的に「暗く」、「緑味が強い」と表現され、両者の色差（△Ｅ）は“著しく異なる”ことが認められた。両者のＬ^＊、ａ^＊、ｂ^＊値の間には相関関係が認められ、原草の測定値から畳表のＬ^＊、ａ^＊、ｂ^＊値の推定式が作成できた。さらに、畳表のＬ^＊、ａ^＊値と畳表色調の「青味」および「白味」程度の官能評価値との間には相関関係が認められ、畳表のＬ^＊、ａ^＊値から畳表色調の「青味」および「白味」程度の官能評価値の推定式が作成できた。また、多重比較検定の結果から、「青味」および「白味」程度の官能評価値の有意差限界値は0.46であった。これらのことから、分光測色計による原草からの畳表色調のＬ^＊、ａ^＊推定値を用いて、畳表色調の「青味」および「白味」程度の官能評価値が推定できた。

［キーワード：原料イグサ、畳表、色調、分光測色計、「青味」および「白味」］

　Measuring Method for Rush Color with a Spectrophotometer, and Estimation of Tatami Facing Color from Rush Color. FUJITOMI Shinichi, Ikufumi KITAHARA and Tsuyoshi SUMIYOSHI (Fukuoka Agric. Res. Cent., Chikushino, Fukuoka 818-8549, Japan) Bull. Fukuoka Agric. Res. Cent. 19: 37 - 40 (2000)

　We examined and established a convenient method for estimating the degree of 'blueness' and 'whiteness' of tatami facing color that is expressed characteristically from the rush color with a spectrophotometer.　

　In the measuring method for rush color using a spectrophotometer, when measuring a selected rush without weighting the middle section of beyond 120cm long as a point of measurement, stable results were obtained. It was concluded that the smallest number of measurements required for times calculating from the coeffcient for variety of measuring values of a^＊were 20 measurements.

　Rush color could represent sensitivity as 'Lightness is darker.' and 'Greenness is stronger.' compared tatami facing color. Then, the color between the two was different appreciably. But a positive correlation was observed between the values of L^＊, a^＊, b^＊ in the two. An estimated formula calculating the values of L^＊, a^＊,b^＊in tatami facing color from rush color was made up.

　Furthermore, a correlation between the measuring values of L^＊, a^＊and the evaluating values of 'blueness' and 'whiteness' in tatami facing color was concluded. The correction served to make a formula for calculating the evaluating values　of 'blueness' and 'whiteness' from their of L^＊, a^＊in tatami facing color. From the results of multiple comparison tests, the limit of significant difference was 0.46 in their evaluating value.

　From these results, it became possible to estimate the evaluating values of 'blueness' and 'whiteness' of tatami facing color based on the measured values of L^＊ and a^＊of rush color with a spectrophotometer.