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CreatingColors
There are two ways to create colors in a photograph. One method,called additive, starts with three basic colors and adds themtogether to produce some other colors. The second method, calledsubtractive, starts with white light (a mixture of all colors in the spectrum)and by taking away some or all other colors leaves the one desired.
In the additive method separate colored lights arecombined to produce various other colors. The three additive primarycolors are green, red and blue (each proportions, about one third of thewavelengths in the total spectrum). Mixed in varyingproportions, they can produce all colors.
Green and red light mix to produce yellow, redand blue light mix to produce magenta, green and blue mix toproduce cyan. When equal parts of all three of theseprimary colored beams of light overlap, the mixture appears white to the eye.Inthe subtractive process, colors are produced when dye (as in paint or colorphotographic materials) absorbs some wavelengths and so passes on only part ofthe spectrum. The subtractive primaries are cyan (ablulish green), magenta (a purplish pink), and yellow; these are the pigments or dyesthat absorb red, green and bluewavelengths, respectively, thus subtracting them from whitelight. These dye colors are the complementary colors tothe three additive primaries of red, green and blue. Properlycombined, the subtractive primaries can absorb all colorsof light, producing black. But, mixed in varyingproportions they too can produce any color in the spectrum.Whethera particular color is obtained by adding colored lights together or by subtracting some light from the total spectrum, theresult looks the same to the eye. The additive process was employed for earlycolor photography. But the subtractive method, while requiring complexchemical techniques, has turned out to be more practical andis the basis of all modern color films.
全文翻譯：創造顏色有兩種方法可以使照片具有色彩。一種叫加色法，通過把三種基本顏色相疊 加以產生其它色彩。
另一種叫減色法，通過去除白色(其實是光譜中所有顏色相混合的結果) 中的某些或其它所有色彩而把所需的色彩留下來。在加色法中，不同顏色的光線混合以產生其它各種色彩。加色法三原色是綠、紅和藍(其中每一種占據總光譜中三分之一的波長)。這三種色彩以不同比例相疊加可以產生所有色彩。綠光和紅光疊加可產生黃色，紅光與藍 光疊加可產生品紅色，綠光與藍光疊加可產生青綠色。當這三種原色光以相同比例疊加時，眼睛所見的就成為白色。
而在減色法中，染料(比如在繪畫顏料或彩色照相材料中)吸收了部分波長而只允許分光譜通過，從而產生各種色彩。減色法三原色是青綠色、品紅(略帶紫色的粉紅色)和黃色；也就是可分別吸收紅光、綠光和藍光的色料或染料，從而去除白色光 中的這些色彩。這些染料色是加色法的三原色紅、綠、藍的相互補充。
適當組合時，減色法三原色能吸收光線中的所有色彩，產生黑色。但當它們以不同的比例疊加時，也能產生光譜中所有顏色。不論某種顏色是通過把不同色彩的光線疊加還是把光譜中某些顏色的光去除掉而產生的，它的視覺效果是一樣的。早期彩色攝影采用加色法。 但減色法盡管需要復雜的化學技術，最終比前者更加實用，并成為現代彩色電影的基礎。
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