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In colorimetry and color theory, colorfulness, chroma, and saturation are related but distinct concepts referring to the perceived intensity of a specific color. ''Colorfulness'' is the visual sensation according to which the perceived color of an area appears to be more or less chromatic.〔, page 87.〕 Chroma is the colorfulness relative to the brightness of a similarly illuminated area that appears to be white or highly transmitting. Therefore, chroma should not be confused with colorfulness.〔() Colorfulness Vs. Chroma〕 Saturation is the colorfulness of a color relative to its own brightness.〔Mark D. Fairchild. “(Color Appearance Models: CIECAM02 and Beyond )”. Slides from a tutorial at the IS&T/SID 12th Color Imaging Conference. 9 November 2004. Retrieved 19 September 2007.〕 Though this general concept is intuitive, terms such as ''chroma'', ''saturation'', ''purity'', and ''intensity'' are often used without great precision, and even when well-defined depend greatly on the specific color model in use. A highly colorful stimulus is vivid and intense, while a less colorful stimulus appears more muted, closer to gray. With no colorfulness at all, a color is a “neutral” gray (an image with no colorfulness in any of its colors is called ''grayscale''). With three color appearance parameters—colorfulness (or chroma or saturation), lightness (or brightness), and hue—any color can be described. == Saturation == Saturation is one of three coordinates in the HSL and HSV color spaces. The saturation of a color is determined by a combination of light intensity and how much it is distributed across the spectrum of different wavelengths. The purest (most saturated) color is achieved by using just one wavelength at a high intensity, such as in laser light. If the intensity drops, then as a result the saturation drops. To desaturate a color of given intensity in a subtractive system (such as watercolor), one can add white, black, gray, or the hue's complement. Various correlates of saturation follow. ; CIELUV : The ''chroma'' normalized by the lightness: : where is the chromaticity of the white point, and chroma is defined below.〔, page 88.〕 By analogy, in CIELAB this would yield: : This definition is inspired by experimental work done with the intention of remedying CIECAM97s's poor performance.〔 〕 ''M'' is proportional to the chroma ''C'' (), thus the CIECAM02 definition bears some similarity to the CIELUV definition. An important difference is that the CIECAM02 model accounts for the viewing conditions through the parameter ''F''''L''.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「colorfulness」の詳細全文を読む スポンサード リンク
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