問73
頻出度★☆☆
プリンタなどの印刷において表示される色について, シアンとマゼンタとイエローを減法混色によって混ぜ合わせると, 理論上は何色になるか。
平成26年度 秋期 ITパスポート試験 問73
テクノロジ系情報メディア › マルチメディア応用
This question's explanation and your answers so far.
解説
問 73
Incorrectア
It does not become blue. Blue (B) is a primary color on the additive side (the RGB primaries of light); in subtractive mixing, blue is the color obtained by overlaying the two colors magenta and cyan. If yellow is added as well, the blue component is also absorbed, so mixing all three colors can never result in blue.
Incorrectイ
It does not become red. In subtractive mixing, red is obtained by overlaying the two colors magenta and yellow. If cyan is added to that, the red component is absorbed, so mixing all three colors makes the red disappear and the result darker.
- ウ
正解 The correct answer is “ウ Black”. Printing on devices such as printers shows color through “subtractive color mixing”: part of the wavelengths of the white light hitting the paper is absorbed (subtracted) by the ink, and the remaining light reaches our eyes. The three primary colors of subtractive mixing are cyan (C), magenta (M), and yellow (Y): cyan absorbs the red component of light, magenta absorbs the green component, and yellow absorbs the blue component. When all three are overlaid, the red, green, and blue components are all absorbed and no light is reflected back, so the result is theoretically black. Note that in actual printing, the limited purity of inks means that overlaying the three colors only produces a muddy brownish tone without a deep black, so in practice black (K) is added and four colors, CMYK, are used.
Incorrectエ
It does not become green. In subtractive mixing, green is obtained by overlaying the two colors cyan and yellow. If magenta is added on top, the green component is absorbed, so no green remains when all three colors are mixed.
ここがポイント
- The three primary colors of subtractive mixing (printing, ink) are cyan, magenta, and yellow. The more you mix, the more light is absorbed and the darker it gets, and all three together theoretically produce black. By contrast, the three primary colors of additive mixing (displays, light) are red, green, and blue; the more you mix, the brighter it gets, and all three together produce white.
- Also remember the two-color combinations in subtractive mixing: cyan + magenta = blue, magenta + yellow = red, yellow + cyan = green. In actual printing, three colors alone cannot produce a sufficiently deep black, so CMYK, which adds black, is used.
用語