Ways to CreateColors in a Photograph

There are two waysto create colors in a photograph.One method called additive,starts with threebasic colors and adds them together to produce some other color. The second

method,calledsubtractive,starts with white light(a mixture of all colors in thespectrum)and,by taking away some or all other colors,leaves the one desired.

In the additivemethod,separate colored lights combine to produce various other colors.Thethree additive primary colors are green,red and blue(each providing about one-

third of thewavelengths in the total spectrum).Mixed in varying proportions,they canproduce all colors.Green and red light mix to produce yellow,red and blue lightmix to

produce magenta(apurplish pink);green and blue mix to produce cyan(a bluish green).When equalparts of all three of these primary-colored beams of light overlap（重

叠）,the mixtureappears white to the eye.

In the subtractiveprocess colors are produced when dye（染料）absorbs some wavelengths and so passes on only part of thespectrum.The subtractive primaries are

cyan,magenta andyellow; these primaries or dyes absorb red,green and blue wavelengthsrespectively,thus subtracting them from white light. These dye colors are the

complementary colorsto the three additive primaries of red,green and blue.Properly combined,thesubtractive primaries can absorb all colors of light, producing

black.But,mixed invarying proportions,they too can produce any color in the spectrum.

Whether a particularcolor is obtained by adding colored lights together or by subtracting somelight from the total spectrum,the result looks the same to the eye.The additive

process was employedfor early color photography. But the subtractive method,while requiring complexchemical techniques,has turned out to be more practical and is the

basis of all moderncolor films.What does thepassage mainly discuss?

A.Recentdevelopments in camera technology.

B.How to make whitelight.

C.The additive andsubtractive methods of producing color.

D.The discovery ofthe spectrum.