Absolute Beginner's Guide to Digital Photography

When white light (which contains all colors) shines on paper (or passes through film),

the CMY inks or dyes absorb their opposite colors. Cyan ink absorbs red light, thus

subtracting red from the image. Magenta absorbs green, and yellow absorbs blue.

The color wheel is used in photography, printing, and computer monitors. Red,

green, and blue (RGB) are primaries in additive systems like television. Cyan,

magenta, and yellow (CMY) are the subtractive primaries in photography and print-

ing processes.

In the additive process, three beams of colored light combine to produce all other

colors (see Figure 20.2). Green plus blue produces cyan, blue plus red produces

magenta, and red plus green produces yellow. White is produced when all three col-

ors mix in equal amounts.

294 ABSOLUTE BEGINNER’S GUIDE TODIGITAL PHOTOGRAPHY

FIGURE 20.1

Color wheel.

Green

Cyan

Blue

Ye l l o w

Red

Magenta

FIGURE 20.2

Additive

process.

Red Green

Blue

In the subtractive process, colors are produced when dyes or inks absorb color (see

Figure 20.3). Inks of the three subtractive primaries—cyan, magenta, and yellow—

here overlap on a white sheet of paper. White light, the illumination, is a mixture of

all wavelengths of light. Where the cyan and magenta inks overlap, they absorb red

and green; only blue is reflected from the paper. Where magenta and yellow over-

lap, only red is reflected. A mixture of yellow and cyan inks reflects only green. If

inks of all three colors are mixed, all the light is absorbed and the paper appears

black. Color film uses the same principle; layers of dye absorb light as it passes

through the film.