Adobe PHOTOSHOP 5.0 User Manual page 237

COLOR MODES In addition to determining the number of colors that can be displayed in an image, color
modes affect the number of channels and the file size of an image. See "Color channels" on page 67.
Bitmap 12K
Bitmapped images are
made up of 1 bit of
color (black or white)
per pixel, and require
the least amount of
disk space.
Grayscale 90K*
Grayscale images are
made up of 8 bits of
information per pixel
and use 256 shades of
gray to simulate
gradations in color.
Duotone 90K
Duotone mode is
used for monotones,
duotones, tritones,
and quadtones. These
images are grayscale,
single-channel images
with 8 bits per pixel.
Multichannel 90K
Multichannel images
have 8 bits per pixel,
and are used for special-
ized printing purposes.
*Grayscale, RGB, and CMYK images can also be created with 16-bit channels. Although images
with 16-bit channels are significantly larger, they can reproduce finer distinctions in color.
Indexed color 90K
Indexed-color images
are single-channel im-
ages (8 bits per pixel)
that use a color lookup
table containing 256
colors. Limited editing is
available in this mode.
RGB color 270K*
RGB images use three
colors to reproduce up
to 16.7 million colors
on-screen. RGB images
are three-channel
images, so they contain
24 (8 x 3) bits per pixel.
CYMK color 359K*
CMYK images consist of
the four colors used to
print color separations.
They are four-channel
images, containing
32 (8 x 4) bits per pixel.
Lab color 270K
Lab images use three
components to represent
color. They are
three-channel images
containing 24 (8 x 3)
bits per pixel.
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